MEDI-THERM II
HYPER/HYPOTHERMIA MACHINE
MTA5900 SERIES
SERVICE MANUAL
LISTED 303L
P/N 10187-000 7/98
www.gaymar.com P/N 10187-000 7/98
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
Before you begin . . .
CAUTION
Federal law restricts this device to sale by
or on the order of a physician.
SAFETY PRECAUTIONS
WARNING
• Repairs should be performed only by qualified
personnel such as certified biomedical
electronics technicians or certified clinical
engineers familiar with repair practices for
servicing medical devices, and in accordance
with the Medi-Therm II Service Manual.
• Always perform the FUNCTIONAL CHECK
AND SAFETY INSPECTION (section 7.3, p. 20)
after making repairs and before returning the
Medi-Therm II machine to patient use.
Improper repair may result in death or
serious injury, equipment damage, or
malfunction.
RECEIVING INSPECTION
Upon receipt, unpack the Medi-Therm II machine. Save all
packing material. Perform a visual and mechanical
inspection for concealed damage by removing the
wraparound from the chassis (see page 73). If any damage
is found, notify the carrier at once and ask for a written
inspection. Photograph any damage and prepare a written
record. Failure to do this within 15 days may result in loss
of claim.
Refer to section 7.0 of this Medi-Therm II Service Manual for
additional details.
OPERATING INSTRUCTIONS
For information on operating the Medi-Therm II machine,
refer to the Medi-Therm II Operating Instructions.
Clik-Tite is a registered trademark of Gaymar Industries, Inc.
©1998. Gaymar Industries, Inc. All rights reserved.
Do not return the Medi-Therm II machine to
Gaymar Industries without first contacting
Gaymar's Technical Service Department for
assistance.
Telephone: Direct (716) 662-2551
Toll Free 1 800 828-7341
IMPORTANT
Before operating the Medi-Therm II machine, remove
the compressor shipping brace. See p. 86, figure B.
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
CONTENTS
i
CONTENTS
Table Description Page
1 High Temperature Limits ..........................................................................25
2 RFU Error Codes ........................................................................................35
3 Service Modes .............................................................................................36
4 Celsius/Fahrenheit Conversion .................................................................65
5 Temperature vs. Resistance.......................................................................66
6 Operator Controls/Indicators ...................................................................69
7 Parts List (base) ..........................................................................................75
8 Parts List (head)..........................................................................................76
9 Control/Display Board Parts List ................................................................83
10 Power Supply Board Parts List ...................................................................84
TABLES
Section Description Page
1.0 PATIENT SAFETY .................................................................................... 1
2.0 MACHINE PRECAUTIONS...................................................................... 3
3.0 REPAIR POLICY ........................................................................................ 4
3.1 In-Warranty Repairs ........................................................................... 4
3.2 Out-of-Warranty Repairs ................................................................... 4
4.0 SPECIFICATIONS ..................................................................................... 5
4.1 Physical Specifications ........................................................................ 5
4.2 Thermal Specifications ....................................................................... 5
4.3 Electrical Specifications...................................................................... 6
5.0 PROBE INFORMATION ........................................................................... 7
6.0 THEORY OF OPERATIONS .................................................................... 9
6.1 Machine ................................................................................................ 9
6.2 Interconnections ................................................................................. 11
6.3 Power Supply ....................................................................................... 12
6.4 Machine Functions .............................................................................. 12
7.0 FUNCTIONAL CHECK, SAFETY INSPECTION,
PREVENTIVE MAINTENANCE .............................................................. 18
7.1 Receiving Inspection ........................................................................... 18
7.2 Cleaning Procedures ........................................................................... 18
7.3 Functional Check & Safety Inspection .............................................. 20
7.4 Inspection Form .................................................................................. 33
8.0 TROUBLESHOOTING & SERVICE MODES .......................................... 34
8.1 Service Modes ...................................................................................... 34
8.2 Troubleshooting Charts ..................................................................... 38
9.0 REPAIR PROCEDURES ............................................................................. 57
9.1 Refrigeration System .......................................................................... 57
9.2 Replacing the Power Supply Board ................................................... 60
9.3 Replacing the Control/Display Board ................................................ 61
9.4 Replacing the Top Cover.................................................................... 62
9.5 Replacing Thermostats ....................................................................... 62
9.6 Cleaning the Flow Switch ................................................................... 63
9.7 Replacement Parts .............................................................................. 64
9.8 Shipping/Repacking Instructions........................................................ 64
10.0 REFERENCE TABLES ............................................................................... 65
10.1 Celsius-Fahrenheit Conversion .......................................................... 65
10.2 Temperature vs. Resistance ............................................................... 66
11.0 SERVICE INFORMATION ........................................................................ 67
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
ILLUSTRATIONS
ii
FIGURES
Figure Description Page
1 Typical Warm-up Rate ............................................................................... 6
2 Typical Cooldown Rate............................................................................... 6
3 Medi-Therm II System................................................................................. 8
4 MT590 Test Tool .......................................................................................... 24
5 Initiating Service Mode 1 ............................................................................ 35
6A/6L Troubleshooting Charts .............................................................................. 38
6A Accessing RFU Codes .................................................................................. 38
6B RFU Code 1 .................................................................................................. 39
6C RFU Codes 2, 3, – , E, and L ........................................................................ 40
6D RFU Codes 4, 5 ............................................................................................. 41
6E RFU Codes 6, 7 ............................................................................................. 42
6F RFU Code 8 .................................................................................................. 43
6G RFU Code 9 .................................................................................................. 44
6H RFU Code H (page 1 of 2) ........................................................................... 46
6H RFU Code H (page 2 of 2) ........................................................................... 47
6I Check Water Flow Alert is On (page 1 of 2) ............................................ 48
6I Check Water Flow Alert is On (page 2 of 2) ............................................ 49
6J Pump Motor Not Running .......................................................................... 50
6K Blanket Won't Heat in Auto or Manual Mode (page 1 of 2) ................... 52
6K Blanket Won't Heat in Auto or Manual Mode (page 2 of 2) ................... 53
6L Blanket Will Not Cool (page 1 of 3) .......................................................... 54
6L Blanket Will Not Cool (page 2 of 3) .......................................................... 55
6L Blanket Will Not Cool (page 3 of 3) .......................................................... 56
7 Flow Switch .................................................................................................. 63
8 Circuit Boards and Connectors (head) ..................................................... 67
9 Operator Controls/Indicators .................................................................... 68
10 Heating Flow Diagram ................................................................................ 70
11 Cooling Flow Diagram ................................................................................ 70
12 Refrigeration Flow Diagram ....................................................................... 71
13 Test Setup .................................................................................................... 72
14 Machine Disassembly ................................................................................... 73
15 Parts Diagram (base)................................................................................... 74
16 Parts Diagram (head) .................................................................................. 76
17 Original Thermostat Wiring Diagram ...................................................... 77
17A New Thermostat Wiring Diagram ............................................................ 77
18 System Wiring Diagram ............................................................................. 79
19 Control/Display Board Schematic (sheet 1 of 2) ...................................... 80
20 Control/Display Board Schematic (sheet 2 of 2) ...................................... 81
21 Power Supply Board Schematic ................................................................ 82
22 Control/Display Board ................................................................................ 83
23 Power Supply Board.................................................................................... 84
24 Control/Display Board Block Diagram ...................................................... 85
25 Shipping/Repackaging Instructions ............................................................ 86
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
1.0 PATIENT SAFETY
Use the Medi-Therm II Hyper/Hypothermia machine only under the direction
of a physician.
Review the following precautions and procedures prior to each application:
WARNING
DANGER
• If the patient’s temperature is not responding or does not reach the
prescribed temperature in the prescribed time or deviates from the
prescribed temperature range, notify the attending physician
promptly. Failure to notify the physician promptly may
result in death or serious injury.
• Power interruption will cause the Medi-Therm II machine to go into
a standby mode, resulting in no therapy to the patient. Follow
instructions for desired mode to resume operation. Failure to
resume therapy could result in death or serious injury.
• The Medi-Therm II machine is provided with a means of checking
rectal/esophageal temperature probes. When performing the probe
check, use a disposable protective sheath (Becton-Dickinson catalog
3700 oral sheath or equivalent) on the probe. Failure to use
sheath could result in cross-contamination.
• A physician’s order is required for setting blanket temperature and
for continued use of equipment. At least every 20 minutes, or as
directed by a physician, check patient’s temperature and skin
condition of areas in contact with blanket; also, check blanket water
temperature. Pediatric, temperature-sensitive, and operating room
patients should be checked more frequently. Failure to monitor
patient may result in skin damage or inappropriate patient
temperature.
PEDIATRICS - The temperatures of infants and children are more
responsive to surface heating and cooling than adults. The smaller
the patient, the more pronounced the effect because of the patient’s
higher ratio of skin contact area to body mass.
TEMPERATURE-SENSITIVE PATIENTS - Patients with impaired
peripheral blood circulation caused by vascular diseases and patients
who are incapacitated may be more sensitive to temperature
changes than patients with more normal circulation.
OPERATING ROOM PATIENTS - Patients with poor circulation
associated with inadequate heart function, reduction in blood volume,
and constriction of peripheral blood vessels may deviate from the
normal response to the external application of heat and cold.
PATIENT SAFETY
Do not use the Medi-Therm II machine in the presence of
flammable anesthetics. Risk of explosion can result.
1
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
WARNING
• Avoid placing additional heat sources between the patient and
blanket. Skin damage can result.
Heat applied by the blanket can result in a rise in skin temperature
at the areas of contact. The additional heat rise due to
electrosurgical currents flowing to the dispersive electrode could be
sufficient to cause tissue injury. Each thermal effect by itself may be
completely safe, but the additive effect may be injurious.
1
Keep
additional heat sources from between the patient and the blanket.
• Prevent excessive and/or prolonged tissue pressure and shearing
forces, especially over boney prominences. Skin damage may
result.
Localized skin injury due to tissue compressed between boney
prominences and fluid-filled channels has occurred during prolonged
cardiovascular procedures at blanket temperatures well below the
scientifically established epidermal burn injury threshold.
2
Local ischemia can follow the application of pressures exceeding
capillary pressure resulting in tissue necrosis. This local effect may
be enhanced by generalized impairment of the circulation, local
shearing forces and increased metabolic demand because of tem-
perature elevation. Pathological changes may begin in two (2) hours.
• Keep the area between the patient and the blanket dry. Excessive
moisture may result in skin damage.
The application of heating or cooling may affect the toxicity of
solutions. Prep solutions have been reported to injure the skin
when allowed to remain between patients and water circulating
heating blankets during prolonged procedures.
3
REFERENCES
1 Gendron, F. G. Unexplained Patient Burns. chap. 5, p. 87, Quest Publishing Co., 1988.
2 Scott, Stewart M. Thermal Blanket Injury in the Operating Room. Arch. Surg., vol. 94, p. 181, Feb. 1967; Crino, Marjanne H. Thermal
Burns Caused by Warming Blankets in the Operating Room. Clinical Workshop, vol. 29, pp. 149-150, Jan-Feb 1980; Gendron, Francis
G. Journal of Clinical Engineering, vol. 5, no. 1, pp. 19-26, January-March 1980; Moritz, A. R. and Henriques, Jr., F.C. Studies of
Thermal Injury II. The Relative Importance of Time and Surface Temperature in the Causation of Cutaneous Burns. Am. J. Path., 23:695,
1947; Stoll, Alice M. and Chianta, Maria A. Method and Rating System for Evaluation of Thermal Protection. Aerospace Medicine, vol.
40, no. 11, pp. 1232-1238, Nov. 1969; Stewart, T. P. and Magnano, S. Burns or Pressure Ulcers in the Surgical Patient. Decubitus, vol. 1,
pp. 36-40, 1988.
3 Llorens, Alfred S. Reaction to povidone-iodine surgical scrub, scrub associated with radical pelvic operation. Am. J. Obstet. Gynecol., pp.
834-835, Nov. 14, 1974; Hodgkinson, Darryl J., Irons, George B. and Williams, Tiffany J., Chemical Burns and Skin Preparation
Solutions. Surgery, Gynecology & Obstetrics, vol. 17 pp. 534-536, Oct. 1978.
PATIENT SAFETY
1.0 PATIENT SAFETY
(continued)
CAUTION
• Place a dry absorbent sheet between the patient and the blanket
when using all-vinyl blankets.
A dry absorbent sheet placed between the patient and the Hyper/
Hypothermia Blanket will absorb perspiration. Vinyl blankets with
nonwoven fabric surfaces do not require an absorbent sheet
when using the nonwoven side toward the patient.
• Federal law restricts this device to sale by or on the order
of a physician.
2
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
DANGER
MACHINE PRECAUTIONS
2.0 MACHINE
PRECAUTIONS
Disconnect power before servicing unit.
Risk of electric shock.
WARNING
• Repairs should be performed only by qualified personnel such as
certified biomedical electronics technicians or certified clinical
engineers familiar with repair practices for servicing medical devices,
and in accordance with the Medi-Therm II Service Manual. Improper
repair may result in death or serious injury, equipment
damage, or malfunction.
• Always perform the FUNCTIONAL CHECK AND SAFETY
INSPECTION (section 7.3, p. 20) after making repairs and before
returning the Medi-Therm II machine to patient use. Improper
repair may result in death or serious injury, equipment
damage, or malfunction.
• Some manufacturer’s patient probes may contain compensation
resistors in series with YSI400 series thermistors. Do not use
these probes with the Medi-Therm II machine. Inaccurate
patient temperature readouts will result and
inappropriate therapy may be delivered.
NOTE: Use YSI400 series patient probes or equivalent.
(Refer to the list of recommended probes in section 5.0,
p. 7 PROBE INFORMATION.)
• Do not tip machine over without first draining the water out and
unplugging the power cord. Electrical shock or damage to the
machine can result.
Add distilled water only. Failure to use distilled water may result
in poor machine performance.
• Do not use alcohol, since it is flammable. Alcohol may also
accelerate blanket deterioration.
• Do not operate the machine without water, since damage to
internal components may result.
• Do not overfill. Overfilling may result in overflow because the water
in the blanket drains back into the machine when the machine is
turned off.
CAUTION
3
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
3.0 REPAIR POLICY
3.1 IN-WARRANTY
REPAIRS
3.2 OUT-OF-WARRANTY
REPAIRS
The Medi-Therm II Hyper/Hypothermia machine is warranted free of defects in
material and workmanship for a period of two (2) years, under the terms and
conditions of the Gaymar warranty in place at the time of purchase. The
compressor portion of the machine carries a five (5) year prorated warranty.
The full warranty is available from Gaymar upon request. Medi-Therm II Hyper/
Hypothermia machines can be repaired at the factory or in the field. Upon
customer request, a shipping carton will be provided to safely return the machine
to Gaymar or a qualified Service Center.
For customers who repair Gaymar Medi-Therm II machines at their location, this
manual contains information to allow a qualified biomedical technician, familiar
with practices for servicing medical devices, to make necessary repairs. Service
training for the Hyper/Hypothermia machine is recommended and is available
from Gaymar. For specific details, contact your Gaymar representative or the
Technical Service Department at Gaymar. (See back cover of this manual for
Gaymar telephone numbers.)
All in-warranty field repairs must be authorized by Gaymar’s Technical Service
Department before proceeding.
The following repair options are available when local machine servicing is elected:
I . Defective Component
Replacement parts can be ordered. Specify the Gaymar part number; refer to
Parts List in section 11, pp. 67 - 77 and 79 - 86 of this manual.
2. Defective Printed Circuit (PC) Board
Defective PC boards can be exchanged for replacement boards at a fixed
cost directly from the factory.
3. Defective Top Module
The defective top module can be returned (without base) to the factory for
repair.
4. Machine Repairs
If the Medi-Therm II machine becomes defective and the cause of the
problem cannot be determined, the complete machine can be returned to
the factory for servicing at the purchaser’s expense. This normally represents
the most expensive repair option.
Please contact Gaymar to obtain an RG (returned goods) number prior
to returning the machine.
REPAIRS / WARRANTY
4
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
4.1 PHYSICAL SPECIFICATIONS
SPECIFICATIONS
4.2 THERMAL SPECIFICATIONS
THERMAL SPECIFICATIONS
MTA5942 MTA5900 MTA5901
High Temperature Limits Fixed
(S2) & (S3)
111.2°F (44°C) to 120.2°F (49°C) 109.4°F (43°C) to 120.2°F (49°C) 109.4°F (43°C) to 120.2.°F (49°C)
(Machine will go into REMOVE FROM USE NOW / MACHINE SHUTDOWN condition and audible alarm will be on.)
Low Temperature Limits Fixed
(S1)
26.6°F (-3.0°C) to 36.5°F (+2.5°C) (Machine will go into REMOVE FROM USE NOW / MACHINE
SHUTDOWN condition and audible alarm will be on.)
Add Water Alert Actuation Less than 8 quarts (7.6 liters) of water in the cold reservoir
Check Probe Activation
Temperature (whenever probe is
used)
Below 89.6°F (32°C) or above 113°F (45°C)
Patient Temperature Control
Range for Automatic Mode
89.6°F (32°C) to 105.8°F (41°C)
Blanket Water Temperature
Control Range for Manual Mode
39.2°F (4°C) to 107.6°F (42°C) 39.2°F (4°C) to 105.8°F (41°C) 39.2°F (4°C) to 105.8°F (41°C)
4.0 SPECIFICATIONS
5
PHYSICAL SPECIFICATIONS
MTA5942 MTA5900 MTA5901
Dimensions
37 in. high x 18-3/4 in. deep x 14 in. wide
(94.0 cm high x 47.6 cm deep x 35.6 cm wide)
Weight
149 lb (full); 130 lb (empty); shipping wt, 164 lb
(72.1 kg (full); 62.6 kg (empty); shipping wt, 74.4 kg
Normal Reservoir
Operating Volume
Approximately 10 quarts (9-1/2 liters) distilled water
Operating Ambient
Temperature Range
60°F to 90°F
(15.6°C to 32.2°C)
60°F to 90°F
(15.6°C to 32.2°C)
60°F to 80°F
(15.6°C to 26.7°C)
Dead Head Pressure
8.5 psi max
(58.6 kPa max)
Flow *
16 gph (gallons per hour)
(60.6 liters/hour) *
16 gph (gallons per hour)
(60.6 liters/hour) *
12 gph (gallons per hour)
(45.4 liters/hour) *
* Minimum flow rates through a full size Gaymar Hyper/Hypothermia Blanket
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
4.2 THERMAL SPECIFICATIONS (cont'd)
4.3 ELECTRICAL SPECIFICATIONS
Figure 1—Typical warm-up rate
(with full size blanket)
Figure 2—Typical cooldown rate
(with full size blanket)
SPECIFICATIONS
WARM-UPRATE(typical)
Time (minutes)
Temperature (°C)
0
5
10
15
20
25
30
35
40
45
0 5 10 15 20 25
COOLDOWN RATE (typical)
Time (minutes)
Temperature (°C)
0
5
10
15
20
25
30
35
40
45
0 5 10 15 20 25
6
ELECTRICAL SPECIFICATIONS
MTA5942
MTA5900 MTA5901
Patient Temperature Measurement Accuracy ±0.5°C, ±0.9°F (using Gaymar 400 series probe)
Display Accuracy ±0.3°C, ±0.5°F
Display Resolution
Blanket Water Temperature
1°C, 1°F
Patient Temperature
0.1°C, 0.1°F
Controller Accuracy
Blanket Water Temperature
±0.8°C, ±1.4°F
Patient Temperature
±0.5°C, ±0.9°F
Current Leakage
Chassis 100 microamps maximum
Patient Probe 50 microamps maximum
Input Voltage 120 ± 10 volts 120 ± 10 volts 100, +10, -5 volts
Frequency 60 Hz 60 Hz 50/60 Hz
Power Consumption 1125 watts 1125 watts
1150 watts
Input Current
with compressor and heater ON 11.5 amps 11.5 amps
13.0 amps
with compressor ON, heater OFF 8.5 amps 8.5 amps
8.8 amps
with heater ON, compressor OFF 5.0 amps 5.0 amps
6.0 amps
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
5.0 PROBE
INFORMATION
Disposable Probes
• DP400 Disposable Rectal/Esophageal -
Adult/Small Child (3' [0.9 meters] long, requires adaptor);
YSI400 series type
Reusable Probes
• PAT101 Patient probe—Rectal/Esophageal -
Adult (10' [3.0 meters] long); YSI400 series type
• PAT102 Patient probe—Rectal/Esophageal -
Pediatric (10' [3.0 meters] long); YSI400 series type
• PAT108 Patient probe—Skin surface (10' [3.0 meters] long);
YSI400 series type
Probe Adaptor
• ADP10 Reusable adaptor cable for DP400: connects Gaymar
disposable probe to Gaymar or Cincinnati Sub-Zero
control unit for all applications that call for Baxter/Pharmaseal
No. 66N2700.
• ADP10B Reusable adaptor cable for DP400: connects Gaymar
disposable probe to American Medical Systems control unit or
all applications that call for Baxter/Pharmaseal
No. 66N27100.
PROBE INFORMATION
WARNING
Some manufacturer’s patient probes may contain compensation resistors
in series with YSI400 series thermistors. Do not use these probes with
the Medi-Therm II machine.
Inaccurate patient temperature readouts will result and
inappropriate therapy may be delivered.
NOTE: Use YSI400 series patient probes or equivalent.
(Refer to the list of recommended probes above.)
7
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
Figure 3—Medi-Therm II System
control panel
YSI 400 series or equivalent
patient probe
connector hose
Medi-Therm II
machine
Hyper/Hypothermia
blanket
pinch
clamp
Clik-Tite connector
Quick-disconnects
o
n m
ac
hin
e
e
n
d
Clik-Tite connectors and
representative hose clamps
alternate
slide
clamp
®
MEDI-THERM II SYSTEM
8
SERVICE MANUAL
Medi-Therm II
THEORY OF OPERATION
www.gaymar.com P/N 10187-000 7/98
The Gaymar Medi-Therm II machine provides a means of regulating patient
temperature by supplying temperature-controlled water through a connector
hose to a Gaymar Hyper/Hypothermia blanket. The blanket provides an interface
for heating or cooling the patient. A patient probe senses patient temperature,
which is displayed on the control panel. (See figure 3, p. 8.)
The Medi-Therm II machine controls output water temperature by mixing hot
and cold water from two reservoirs using hot and cold solenoid valves under
microprocessor control. The feedback for control purposes is dependent on the
machine’s operating mode. A circulating pump, heater and refrigeration unit (all
under microprocessor control) are also utilized.
Bimetallic thermostats and associated backup circuitry limit output water
temperature independent of the microprocessor.
OPERATING MODES
The Medi-Therm II machine may be operated in one of three operating modes:
In MANUAL mode, the operator must observe patient temperature and
manually adjust the blanket water set point temperature. An inline blanket
water probe senses the temperature of the water pumped to the blanket and
provides feedback for control purposes to the microprocessor. The patient
temperature may be monitored by use of a patient probe.
In AUTO mode, the operator sets the desired patient temperature. The
patient’s temperature (as sensed by the patient probe) is automatically
regulated to this set point. The patient probe input provides feedback to the
microprocessor so it can adjust water temperature accordingly.
In MONITOR mode, the operator can monitor patient temperature through
the patient probe. No patient therapy is provided. The pump, heater, and hot
and cold solenoid valves are de-energized.
WATER RESERVOIRS
The hot water reservoir contains a small reserve of water. When the blanket
water requires heating, a cartridge heater under microprocessor control quickly
heats the water.
The cold water reservoir maintains approximately 10 quarts (9
1
/2 liters) of water
at approximately 39.2°F (4°C). A cold water reservoir probe provides
temperature feedback to the microprocessor which then cycles a refrigeration
compressor to control the reservoir temperature.
6.0 THEORY OF
OPERATION, SYSTEM
6.1 THEORY OF
OPERATION,
MEDI-THERM II
MACHINE
9
SERVICE MANUAL
Medi-Therm II
THEORY OF OPERATION
www.gaymar.com P/N 10187-000 7/98
WATER TEMPERATURE CONTROL
Hot and cold solenoid valves regulate the flow path by directing water
returning from the blanket to either the hot or cold water reservoir.
Regulating the flow path controls the temperature of water pumped to the
blanket. The microprocessor controls solenoid valve operation. Only one valve
may open at a time:
When the HEAT status light is lit, the hot solenoid valve is open.
Water returning from the blanket circulates through the hot water
reservoir and is heated before being pumped back to the blanket. The
heater, pump, and hot solenoid valve are energized. (See figure 10, p.
70.)
When the COOL status light is lit, the cold solenoid valve is open.
Water returns from the blanket to the cold water reservoir and is
replenished by chilled water from the cold water reservoir before
being pumped back to the blanket. The pump and cold solenoid valve
are energized. (See figure 11, p. 70.) The refrigeration compressor
maintains the
cold water reservoir temperature and operates independently of the
solenoid status.
When the IN-TEMP status light is lit, either the blanket water temperature is
within 1.8°F (1°C) of the setpoint (in MANUAL mode) or the patient
temperature is within 1.8°F (1°C) of the setpoint (in AUTO mode). Water
temperature is controlled by alternating between heating and cooling (See
figures 10 and 11).
REFRIGERATION UNIT
The refrigeration circuit (see figure 12, p. 71) consists of two heat exchangers
operating at two pressures and two devices used to change these pressures. The
first of these devices is the compressor which changes the gas pressure from low
to high. The other device is the capillary tube which reduces the refrigerant
pressure from high to low.
Beginning the cycle at the capillary tube, high pressure liquid refrigerant flows in
the capillary tube and is discharged into the evaporator coil. The evaporator coil,
which is a heat exchanger, receives the refrigerant as a mixture of liquid and
vapor at a pressure low enough so that it boils and absorbs heat from the water
surrounding it.
The heated refrigerant vapor then leaves the evaporator coils, enters the suction
side of the compressor and is compressed, causing its pressure and temperature
to increase. The vapor, much warmer than the ambient air, travels to the
condenser.
The condenser is the other heat exchanger. The condenser fan draws the colder
ambient air over the condenser coils and removes the heat being carried by the
refrigerant and causes it to condense back into liquid refrigerant. This completes
the cycle and the high pressure liquid refrigerant is returned to the capillary tube
to be used over again. The temperature of the water surrounding the evaporator
coil (in the cold water reservoir) is controlled by the microprocessor. The
microprocessor senses the temperature with a cold water reservoir probe and
cycles the compressor relay on and off.
6.1 THEORY OF
OPERATION,
MEDI-THERM II
MACHINE (continued)
10
SERVICE MANUAL
Medi-Therm II
THEORY OF OPERATION
www.gaymar.com P/N 10187-000 7/98
BACKUP SYSTEMS
Backup systems within the Medi-Therm II machine limit the temperature of water
exiting the machine to specified ranges in the event of a failure of the control
system including the microprocessor:
Maximum water temperature is limited by two bimetallic thermostats. If
either of these two thermostats is actuated, a REMOVE FROM USE NOW /
MACHINE SHUTDOWN circuit is triggered which:
• shuts down the pump and heater;
• lights the ALERT and the REMOVE FROM USE NOW / MACHINE
SHUTDOWN indicators; and,
• sounds the audible alarm.
In addition, if the microprocessor is operational, the compressor shuts down, the
displays blank, and the ALERT indicator and audible alarm turn on and off.
Minimum water temperature is limited by a bimetallic thermostat. If this
thermostat is actuated, a REMOVE FROM USE NOW / MACHINE SHUTDOWN
circuit is triggered, which in turn:
• shuts down the pump and heater;
• lights the ALERT and the REMOVE FROM USE NOW / MACHINE
SHUTDOWN indicators; and,
• sounds the audible alarm. In addition, if the microprocessor is
operational, the compressor shuts down, the displays blank, and the
ALERT indicator and audible alarm turn on and off.
See figure 8, p. 67 for base-to-head and control/display board-to-power supply
board connections; figure 18, p. 79 for system wiring diagram; figures 19, 20 and
21, pp. 80, 81, 82 for the electrical schematics; figures 22 and 23, pp. 83 and 84,
for component layouts and part designations; and figure 24, p. 85 for the
control/display board block diagram.
CONTROL/DISPLAY BOARD AND POWER SUPPLY BOARD
The Medi-Therm II machine uses two printed circuit boards (see figure 8, p. 67):
• The control/display board contains the microprocessor circuits, the
display circuits, and all other low voltage control circuits.
• The power supply board contains the power supply, the low voltage
to high voltage interface circuits, and the REMOVE FROM USE NOW
/ MACHINE SHUTDOWN backup safety circuits.
The control/display board connects to the patient probe jack J1 via P2 at J2
and to the digital control assembly panel via P4 at J4. All other connections
from the system’s peripheral devices to the control/display board are made
through the power supply board.
A 26-pin cable connects the control/display board via P1 at J1 to the power
supply board via P3 at J4.
6.1 THEORY OF
OPERATION,
MEDI-THERM II
MACHINE (continued)
6.2 SYSTEM
COMPONENT
INTERCONNECTIONS
11
SERVICE MANUAL
Medi-Therm II
THEORY OF OPERATION
www.gaymar.com P/N 10187-000 7/98
Four cables connect the components in the base of the machine to the PC
boards in the head (see figure 8, p.67):
• A 9-pin connector P6 ties the blanket water probe RT2, cold
water reservoir probe RT1, flow switch S5, and level switch S4 to
the power supply board at J2 and ultimately to the control/display
board.
• A 12-pin connector P7 ties the high voltage devices (pump,
heater, hot solenoid valve SV2, cold solenoid valve SV1, and
refrigeration compressor relay K1) to the interface circuits on the
power supply board, as well as thermostats S1, S2, and S3 to the
high voltage backup circuitry on the power supply board.
• A 6-pin connector P5 connects transformer T1 housed in the
base to the power supply circuitry at J3 on the power supply
board.
• A chassis ground harness from the control/display board
connects to the chassis.
See figure 18, p.79 for the system wiring diagram; figures 19, 20 and 21, pp. 80,
81, 82 for the electrical schematics; figures 22 and 23, pp. 83, 84 for component
layouts and part designations; and figure 24, p. 85 for the control/display board
block diagram.
Power enters the Medi-Therm II machine through circuit breaker CB1 to feed the
refrigeration unit through relay K1. It also then enters the power supply board at
J1 to feed the hot solenoid valve, cold solenoid valve, heater and pump triacs, the
high voltage backup water temperature limiting circuits and transformer T1.
Power to drive the low voltage circuits on the control/display board is derived
from the machine’s power supplies which reside entirely on the power supply
board. The transformer T1 output is rectified and filtered to generate
unregulated positive and negative voltages. Q5, D1, L1 and associated
components are configured as a DC to DC switching regulator in a buck
configuration yielding a nominal output of +5.3 volts DC. Q6 is a linear
regulator with a nominal output of plus twelve (+12) volts DC, while Q7, also
a linear regulator, delivers a nominal output of minus twelve (-12) volts DC.
See figure 18, p. 79 for system wiring diagram; figures 19, 20 and 21, pp. 80, 81,
82 for the electrical schematics; figures 22 and 23, pp. 83, 84 for component
layouts and part designations; and figure 24, p. 85 for the control/display board
block diagram.
The U37 microprocessor is fully dependent on the code stored in the U31
EPROM. When the machine is on, the microprocessor continually cycles through
its main program loop to perform the following:
• Thermistor output measurement (see section 6.4.1, p. 13)
• Digital control panel input (section 6.4.2, p. 13)
• Display update (section 6.4.3, p. 13)
• Peripheral input (section 6.4.4, p. 14)
• Blanket/Patient temperature control (section 6.4.5, p. 15)
• Cold water reservoir temperature control (section 6.4.6, p. 16)
Backup water temperature limiting is achieved independently of the
microprocessor. (See section 6.4.7, p. 16.)
6.2 SYSTEM
COMPONENT
INTERCONNECTIONS
(continued)
6.3 POWER SUPPLY
6.4 MACHINE
FUNCTIONS
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SERVICE MANUAL
Medi-Therm II
THEORY OF OPERATION
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Temperature measurement is achieved using 400 series thermistor beads located
in the blanket water path (blanket water probe RT2), the cold water reservoir
(cold water reservoir probe RT1), and in the patient via the patient probe jack J1.
Under microprocessor U37 control, each of the three beads is connected to
the current source circuitry (U38 and associated components) by a
demultiplexor U49. At the same time, the resulting output voltage created by
the current through the thermistor is presented to an amplifier circuit (U39
and associated components) via multiplexor U50. The amplified voltage is then
applied to a voltage-to-frequency converter U24. A frequency up to 100kHz is
presented to port pin P3.5 of the microprocessor. The microprocessor
converts the incoming frequency to a temperature value.
At regular intervals two compensation resistors R13 and R12 are also
processed in the same manner. These compensation resistors are precision
resistors with values at each end of the probe temperature range of 32°F
(0°C) to 122°F (50°C). The values from the precision resistors are used to
compensate for circuit drift.
User input is entered via a digital control panel. The input from the buttons is
decoded by U45. The “data available” line of U45 is tied to the microprocessor
port pin P3.3. When a button press is decoded and debounced by U45, the
“data available” line goes high and the microprocessor responds by inputting
the decoded value.
For display of measured and set point temperatures, 7 segment LED displays
are utilized:
• The set point display is driven by driver chip U48. The
microprocessor interfaces to it via the data bus at addresses 0FFF8H,
0FFF9H, 0FFFAH, 0FFFBH.
• The patient display is driven by driver chip U6. The microprocessor
interfaces to it via the data bus at addresses 0FFF4H, 0FFF5H,
0FFF6H, 0FFF7H.
• The blanket display is driven by driver chip U5. The microprocessor
interfaces to it via the data bus at addresses 0FFECH, 0FFEDH, 0FFEEH,
0FFEFH.
6.4.1 THERMISTOR
OUTPUT
MEASUREMENT
6.4.2 DIGITAL CONTROL
PANEL INPUT
6.4.3 DISPLAY UPDATE
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THEORY OF OPERATION
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All alarm and status indicators are lit by LED bars driven by inverter/driver
IC’s:
• The alarm latch U53 is the interface between the microprocessor
and the ALERT, ADD WATER, CHECK PROBE, CHECK FLOW, REMOVE
FROM USE NOW / MACHINE SHUTDOWN, SELECT, °F* and °C
drivers via the data bus at address 0FFBFH. A high signal written to
the latch by the microprocessor activates the individual inverter/
drivers to light the corresponding indicator.
• The mode display latch U54 is the interface between
microprocessor and the IN-TEMP, COOL, HEAT, FLOW-OK, AUTO,
MANUAL, and MONITOR drivers via the data bus at address 0FFDFH.
A high signal written to the latch by the microprocessor activates
the individual inverter/drivers.
• The control latch U51 is the interface between the microprocessor
and the two leader light drivers via the data bus at address 0FF7FH.
When this latch is selected, a low signal on the data line from the
microprocessor causes a high signal on the latch output Therefore,
these two LED bar displays are “active low” in the eyes of the
microprocessor in contrast to all the other LED bar displays of the
machine.
The audible alarm is driven either by a high signal from the control latch U51
(from the microprocessor via the data bus at address 0FF7FH) or a high RFU
IN signal from Q10 on the power supply board. A low data line signal from the
microprocessor to U51 causes a high signal on the latch output Therefore, the
alarm is “active low” in the eyes of the microprocessor. NOR gate U40, driver
U26 and transistor Q1 work in conjunction to activate the alarm.
The input buffer U55 is the interface between the microprocessor (via the
data bus at a “read” address of 0FFFEH) and the input signals from the flow
switch S5 and the level switch S4 (which travel from the base through the
power supply board), the probe presence switch within the patient probe jack
J1, and the service mode button S3 on the control/display board. The lines to
the buffer from the peripheral devices are default high (via pull-up resistors).
The level switch S4 will pull its buffer input line low when it senses a sufficient
water level.
The flow switch S5 will pull its buffer input line low when it senses sufficient flow.
The probe presence switch within J1 will pull its buffer input line low when it
senses the presence of the patient probe.
Pressing the service mode switch S3 on the control/display board will pull its
buffer input line low.
* Some models do not have the °C/°F feature.
6.4.3 DISPLAY UPDATE
(continued)
6.4.4 PERIPHERAL INPUT
14
SERVICE MANUAL
Medi-Therm II
THEORY OF OPERATION
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If the machine is in MANUAL mode, the blanket water temperature as sensed
by the blanket water probe is used as the feedback signal for controlling the
water temperature to the MANUAL mode set point temperature.
If the machine is in AUTO mode, the patient temperature as sensed by the patient
probe connected to the patient probe jack is used as the feedback signal for
controlling the patient temperature to the AUTO mode set point temperature. The
machine accomplishes this by adjusting the water temperature.
For water temperature control, the microprocessor control system outputs a
pulse train to each solenoid valve. The pulse train to the hot solenoid (and also
heater) is the complement of the pulse train to the cold solenoid. The pulse train
duty cycle depends on the magnitude and sense of the control signal calculated by
the microprocessor. That is, while the solenoids are each either on or off, the
ratio of on time to off time is proportional to the calculated control signal
amplitude. For large differences between set point and probe temperatures, the
output to each solenoid valve will be either on or off. For differences approaching
zero, the outputs to the solenoid valves (and heater) will switch on and off, with
the on and off times automatically adjusted to maintain a probe temperature
equal to the set point.
The circulating pump is energized whenever the unit is in AUTO or
MANUAL modes.
The control latch U51 on the control/display board is the interface between the
microprocessor (via the data bus at address 0FF7FH) and the peripheral drivers
on the power supply board.
Interface circuitry on the power supply board consists of U1, U2, U7, U8, Q3,
Q4, Q8, Q9, and associated components. U1, U2, U7, and U8 are optically
coupled triac drivers used to control their respective triacs (Q3, Q4, Q8, and
Q9); these combinations provide electrical isolation between the low voltage
microprocessor control circuits and the line voltage circuits.
The heater, pump, hot solenoid valve, and cold solenoid valve are individually
controlled by the microprocessor through latch U51 on the control/display
board. A high signal on the data line from the microprocessor causes a low signal
on the appropriate output line of U51 which then sinks current from the power
supply board to activate the peripheral devices.
Pin 11 of U51 on the control/display board and U8 and Q9 of the power
supply board control the cold solenoid valve while pin 9 of U51 on the
control/display board and U7 and Q8 of the power supply board control the
hot solenoid valve. Pin 8 of U51 on the control/display board and U2 and Q4
of the power supply board control the circulating pump. Pin 7 of U51 on the
control/display board and U1 and Q3 of the power supply board control
power to the heater.
6.4.5 BLANKET / PATIENT
TEMPERATURE
CONTROL
15
SERVICE MANUAL
Medi-Therm II
THEORY OF OPERATION
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The control latch U51 on the control/display board is the interface between
the microprocessor (via the data bus at address 0FF7FH) and the refrigeration
compressor relay driver on the power supply board. A high signal on the
appropriate data line causes a low signal at pin 6 of U51 on the control/display
board, which then activates Q12 on the power supply board. Q12 on the
power supply board is the interface between the control/display board and the
coil of the power relay K1 located in the machine base. The microprocessor
switches power through the relay to the refrigeration compressor at cut-out
and cut-in temperatures of 38°F (3.3°C) and 42.5°F (5.8°C). These
temperatures are sensed by the cold water reservoir probe RTl located in the
water reservoir. (See figure 12, p. 71.) Control of the cold water reservoir
temperature takes place whenever the machine is on.
The power supply board includes the REMOVE FROM USE NOW / MACHINE
SHUTDOWN circuitry, which includes U3, U4, U5, U6, U9, U10, D2, D3, Q1,
Q2, their interconnected components, and fixed, nonadjustable thermostats
S2, S3, and S1 located in the base. Under normal circumstances, Q1 and Q2
are kept turned on by the action of R7, C10, and D4 and R5, C15, and D5 to
complete the conduction path for the heater and pump. If the blanket water
falls into the low temperature limit range, S1 will open. If the blanket
temperature rises into the high temperature limits ranges, S2 and/or S3 will
open. (See section 4.2 Thermal Specification table, page 5, for the correct high
or low temperature limits with corresponding model number of your
machine.) When any one of these thermostats opens, it directly interrupts the
circuit and shuts off the pump and heater; at the same time, full line voltage
will appear between J1-2 and J1-3. In this case, U5 and U10 will be turned on
by the action of R4, D3, and associated parts while U3 and U9 will be turned
on by the action of R6, D2, and associated parts. U5 prevents Q2 from
turning on and U3 prevents Q1 from turning on even if the open
thermostat(s) closes again. The output of either U9 or U10, through buffer
Q10, signals the microprocessor that a thermostat has tripped and that a
REMOVE FROM USE NOW / MACHINE SHUTDOWN condition has resulted.
Thus, should any thermostat (S1, S2, or S3) trip, the heater and pump are
shut off and the microprocessor is notified.
On the control/display board, a high signal from Q10 of the power supply
board feeds NOR gate U40 to drive the audible alarm, feeds driver U52 to
light the REMOVE FROM USE NOW / MACHINE SHUTDOWN LED, and feeds
driver U11 to light the ALERT LED. All this is done independent of the
microprocessor. This same signal is sent to port pin P3.2 of the
microprocessor through C1, R1, and driver U11.
If the microprocessor is operational at the event of a high signal from Q10 of
the power supply board, the signal at P3.2 causes the microprocessor to shut
off the 7 segment displays, flash the ALERT LED and light the REMOVE FROM
USE NOW / MACHINE SHUTDOWN LED, toggle the audible alarm, store the
appropriate RFU* code indicating the reason for the shutdown, turn off the
heater and pump triacs Q3 and Q4, turn off the solenoid triacs Q8 and Q9,
and turn off the compressor transistor Q12. Anytime the microprocessor
6.4.6 COLD WATER
RESERVOIR
TEMPERATURE
CONTROL
6.4.7 BACK-UP WATER
TEMPERATURE
LIMITING
* RFU = REMOVE FROM USE NOW / MACHINE SHUTDOWN
16
SERVICE MANUAL
Medi-Therm II
THEORY OF OPERATION
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goes into a shutdown condition it also sends an output signal from port pin
P3.4, through U40 of the control/display board, to command, via Q11, U4, and
U6 on the power supply board, a REMOVE FROM USE NOW / MACHINE
SHUTDOWN condition. The process of turning off the heater and pump triacs
Q3 and Q4 by the microprocessor removes power from the REMOVE FROM
USE NOW / MACHINE SHUTDOWN circuitry on the power supply board
which then allows the indicators on the control/display board to toggle under
microprocessor control. This shutdown condition by the microprocessor
program will remain until the machine is powered down. If, upon machine turn
on, the fault condition still exists, attempting to resume therapy (which would
turn on the pump and possibly heater) will replace power to the REMOVE
FROM USE NOW / MACHINE SHUTDOWN circuits on the power supply board
and cause the REMOVE FROM USE NOW / MACHINE SHUTDOWN condition to
recur.
Also, if during normal operation, the microprocessor senses internal
problems, it will attempt a shutdown as described above. (See table 2, section
8.1, p. 35.)
If the microprocessor is nonoperational at the event of a signal from Q10 of
the power supply board, the user is notified of the REMOVE FROM USE NOW
/ MACHINE SHUTDOWN condition by the fact that the above mentioned
indicators are on continuously. In addition, there are separate, redundant
circuits on the power supply board, each triggered by any of the thermostats,
that insure that the pump and heater remain off even if the thermostat cools
sufficiently to close again. The REMOVE FROM USE NOW / MACHINE
SHUTDOWN condition remains latched and can be cleared only by an operator
intervention in the form of turning the machine circuit breaker off. If, upon
machine turn on, the fault condition still exists, attempting to resume therapy
will cause the REMOVE FROM USE NOW / MACHINE SHUTDOWN condition to
recur.
6.4.7 BACK-UP WATER
TEMPERATURE
LIMITING
(continued)
17
www.gaymar.com P/N 10187-000 7/98
Concealed Damage
After unpacking the Medi-Therm II machine, inspect the machine for concealed
damage. Save all packing material and carefully describe or photograph the
damage. Notify the carrier at once and ask for an inspection (in writing). Failure
to do this within 15 days may result in loss of claim. Do not return the machine
to GAYMAR — call Gaymar's Technical Service Department for advice.
Before placing the Medi-Therm II machine into service, perform a FUNCTIONAL
CHECK AND SAFETY INSPECTION (pp. 20 to 33).
IMPORTANT
Before operating the Medi-Therm II machine, remove the
compressor shipping brace. (See p. 86, figure B.)
Fluid System
Use distilled water to retard algae growth and mineral buildup. Change the
distilled water monthly or more often depending upon use.
The water circulation system, including blankets, should be cleaned every month
to retard algae growth.
To clean the fluid system, drain the machine and prepare an algaecidal solution
according to manufacturer’s instructions. Use Gaymar product catalog MTA33,
or AirKem A-33 or equivalent available from Enviro-San, Inc., 2361 Wehrle
Drive, Williamsville, NY 14221 (telephone: (716) 634-9900). Add the solution
to the machine, attach blankets, set the machine in MANUAL mode to a
setpoint temperature of 27°C (80.6°F) and circulate the solution for 12 hours.
Drain the solution and refill the machine with distilled water. Algaecide
solution (MTA33 or equivalent) may be readded to the water and left in the
machine in the recommended concentration to further retard algae growth.
• Do not exceed proper algaecidal solution concentration.
Excessive algaecide may cause foaming, which can
damage the circulating pump.
• Do not use bleach (sodium hypochlorite).
Bleach will damage the heating element in the machine,
which could result in excessive leakage current.
Compressor
Dirt that has accumulated on the condenser coils and cooling fins within the
machine will reduce the efficiency of the compressor and should be removed with
a vacuum cleaner or compressed air hose. This will require removal of the rear
baffle assembly. This should be checked monthly or more frequently depending
upon use. (See figure 14, p. 73.)
CAUTION
7.0 FUNCTIONAL CHECK, SAFETY INSPECTION, AND PREVENTIVE MAINTENANCE
7.1 RECEIVING
INSPECTION
PROCEDURES
7.2 CLEANING
PROCEDURES
18
RECEIVING INSPECTION
& CLEANING PROCEDURES
SERVICE MANUAL
Medi-Therm II
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Pump
Pump motor should be oiled once a year with 3-4 drops of general purpose
motor oil in the locations identified on the pump label.
Panel Exterior
Clean the control panel and panel exterior with a cloth dampened with
isopropyl alcohol.
Blankets
Outside surfaces of standard blankets may be cleaned with a damp cloth and mild
detergent to prevent algae growth. To clean the insides, attach the blankets to
the machine and follow instructions for section 7.2, p. 18, CLEANING
PROCEDURES, Fluid System.
NOTE: Exposure to harsh chemicals will cause blankets to lose flexibility and
resistance to cracking.
Probe Check Well
The Probe Check Well should be cleaned with a small tubular brush and
detergent, and then wiped with a commercial disinfectant.
When performing the PROBE CHECK, use a disposable protective
sheath (Becton-Dickinson catalog 3700 oral sheath or equivalent)
on the probe.
Failure to use sheath could result in cross-contamination.
Probes
Do not autoclave. Clean with a damp cloth and mild detergent. Wipe dry.
Probes are made of PVC. If probe must be sterilized, use any cold sterilization
means except alcohol, which may accelerate probe deterioration. Always wipe
dry.
If gas sterilization is necessary, probes should be handled like any other PVC
product. Probes are made of PVC.
Reusable probes may be cleaned with a damp cloth and mild detergent. Always
wipe dry. Exposure to harsh chemicals will cause probe to lose flexibility and
resistance to cracking.
Disposable probes should be discarded after use.
NOTE: Exposure to harsh chemicals will cause probe to lose flexibility and
resistance to cracking. Do not use damaged temperature probes.
Discard probes having visible pinholes, cracks or abrasions.
7.2 CLEANING
PROCEDURES
(continued)
WARNING
CLEANING PROCEDURES
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SERVICE MANUAL
Medi-Therm II
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To assure the optimum performance, dependability and safety, the following
should be performed every three (3) months or as specified in the facility's
preventive maintenance program.
An Inspection Form is provided at the end of this section to facilitate and
document the inspection process. Lower case letters preceding the subheadings
within section 7.3 correspond to the lines on the INSPECTION FORM.
Always perform the FUNCTIONAL CHECK AND SAFETY INSPECTION after
making repairs and before returning the Medi-Therm II machine to
patient use.
Improper repair may result in death or serious injury,
equipment damage, or malfunction.
The following test equipment (or equivalent) is required to perform the
preventive maintenance/functional check procedures:
• GAYMAR TPT9 Flowmeter/Temperature Tester
• GAYMAR TFC1 Mercury Thermometer (±1°C accuracy);
-2°C to +52°C range
• GAYMAR DBK9 Blanket Connector Hose
* • GAYMAR MT590 Medi-Therm II Test Tool, or
GAYMAR PRK2 Patient Temp Simulator Kit, or
Precision Decade Box (0-10K ohms, 0.2% accuracy, 1 ohm
increments)
• GAYMAR DHP901 or DHP813 Hyper/Hypothermia Blanket
* • GAYMAR MT590 Medi-Therm II Test Tool, or
6" (approximately 150 cm) Shorting Jumper
• Ground Resistance Checker
• Current Leakage Tester
• Static Control Wrist Strap
* The GAYMAR MT590 Medi-Therm II Test Tool is a dedicated test tool
available from Gaymar Industries. This tool was designed to allow for more
convenient and safer testing of the high temp backup thermostats by
eliminating the need to remove the lower wraparound cover and avoiding
the use of a shorting jumper that could be accidentally left inside the
machine. In addition, the test tool can be used to monitor input/output
signals between the head and base of the machine through the use of
indicator lights. This feature can be of great value during any troubleshooting
process. This test tool also provides a patient probe simulator which allows
testing of the machine without a precision decade box.
For more information on the MT590 Test Tool, contact the Gaymar
Technical Service Department.
7.3 FUNCTIONAL CHECK &
SAFETY INSPECTION
FUNCTIONAL CHECK &
SAFETY INSPECTION
WARNING
Test Equipment
Requirements
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SERVICE MANUAL
Medi-Therm II
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7.3 FUNCTIONAL CHECK &
SAFETY INSPECTION
(continued)
FUNCTIONAL CHECK &
SAFETY INSPECTION
DANGER
Disconnect power before servicing unit. Risk of electrical shock.
Follow the following procedures carefully, paying particular attention to test
setups. Any deviation from the setups, procedures, or test equipment may result
in incorrect or misleading results.
Before making any repairs, be sure to recheck your test setup, procedure, and
test equipment.
Test equipment should be calibrated in accordance with NIST (National Institute
of Standards and Technology) guidelines to insure accurate readings.
a) Condition of Chassis
The following inspections should be performed:
1. The chassis should be clean and relatively free of rust and corrosion.
2. Exterior screws should be tight
3. Legends, markings, and operator instructions should be legible.
4. Dirt that has accumulated in vents and cooling fins within the
machine should be removed with a vacuum cleaner or compressed
air hose. This will require removal of the rear baffle assembly.
5. Check that the casters are tight and functioning properly.
6. The quick-disconnect fittings on the machine may become stiff and
difficult to engage. If so, apply a silicone-base lubricant to the inside
of the machine fittings and the outside of the blanket connector.
7. Clean the Probe Check Well according to the procedure described
in section 7.2, p. 19.
8. Inspect the fluid system for debris and any sign of algae growth.
Clean according to Cleaning Procedures, Fluid System (section 7.2).
b) Attachment Plug
Examine the attachment plug on the line cord to be sure that it is in
good condition.
c) Line Cord and Strain Reliefs
Examine the line cord along its entire length for physical damage, such as cuts
or cracked insulation. A damaged line cord should be replaced rather than
repaired. Check the quality of the strain reliefs at both ends of the line cord.
d) Circuit Breaker
A worn out circuit breaker can be responsible for intermittent shutoffs,
with no other apparent indications of failure.
Examine the physical condition of the circuit breaker, paying particular
attention to the push-on terminals at the rear of the breaker. Terminals
should be snug. Replace breaker and/or terminals if there is discoloration
or any indications of heating.
Cycle the switch on and off several times. The switch should have a
positive engagement (“click”) for the OFF and ON positions.
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e) Condition of Lights and Alarm
Plug in the Medi-Therm II machine and turn it on. Press and hold the
TEST LIGHTS button. The right and left halves of the display panel should
light and blank alternately (along with the audible alarm). The four status
legends (FLOW OK, HEAT, IN-TEMP, and COOL), the ALERT legend and its
four (triangular) indicators, and the three mode legends and SELECT
heading should be lit. The three temperature displays should indicate
“888”, “888.8”, and “888.8”. The two temperature scale indicators (“°C”
and “°F”) * and the two lines connecting SET POINT to both the
BLANKET and PATIENT DISPLAY should be lit. The audible alarm should
sound. Replace any LED’s which do not light.
f) Flow
To measure the machine’s flow rate and check the flow switch actuation,
perform the following:
1. Fill machine with distilled water until green band on float stem is
fully visible.
2. Connect the test setup shown in figure 13, p.72.
3. Turn machine on. Set machine in MANUAL mode.
4. Increase the temperature set point to light the HEAT status light.
Note the flow rate. The FLOW OK indicator should be lit.
5. Decrease the temperature set point to light the COOL status light.
Note the flow rate. The FLOW OK indicator should be lit.
6. The flow rate in both modes should exceed 16 GPH (60.6 liters/hr)
for an MTA5942/MTA5900 and 12 GPH (45.4 liters/hr) for an
MTA5901.
NOTE: If the unit has been completely drained, air can be
trapped in the pump causing the flow to be decreased.
To clear the air, turn the unit off, wait approximately
one minute, and start again from step 3.
7. Kink the hose to stop the flow. The CHECK WATER FLOW indicator
should light, the FLOW OK indicator should go out, and the ALERT
indicator should flash on and off.
g) Level Switch Actuation
To test the actuation of the level switch, perform the following:
1. Fill machine with distilled water until green band on float stem is
fully visible. The ADD WATER indicator should be off.
2. Connect a DBK9 hose to a supply fitting on the machine and
direct the other end to a drain or gallon (4 liter) container.
3. Turn machine on. Set machine in MANUAL mode. Adjust the
temperature set point to 39.2°F (4°C) (COOL status light on).
4. Allow water to drain until bobber has bottomed out on the drain
screen (about 3 quarts or 3 liters). The ADD WATER indicator
should be lit.
5. Refill machine until the green band is fully visible and verify that the
ADD WATER indicator goes out.
* Some models do not have the °C/°F feature.
7.3 FUNCTIONAL CHECK &
SAFETY INSPECTION
(continued)
FUNCTIONAL CHECK &
SAFETY INSPECTION
22
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
h) Cold Water Reservoir Controller
To check the cold water reservoir controller, perform the following:
1. Fill machine with distilled water until green band on float stem is
fully visible.
2. Connect the test setup shown in figure 13, p. 72.
NOTE: To minimize the test time for this test only, do not
connect a blanket as shown in figure 13. Connect the return
line of connector hose to the TPT9 tester.
3. Turn machine on and push the MANUAL mode button.
4. Set the Temperature Setpoint to 39.2°F (4°C).
5. Verify that the machine can supply water anywhere within the
37.4°F (3°C) to 42.8°F (6°C) range as measured by the
thermometer and that the compressor turns off one time. (This will
take 15-30 minutes, depending upon room temperature and other
conditions. The use of a blanket for this test can extend this time up
to 60 minutes.)
i) Blanket Water Temperature Controller and Display Test
To check the temperature controller, perform the following:
1. Fill machine with distilled water until green band on float stem is
fully visible.
2. Connect the test setup shown in figure 13, p. 72.
3. Turn machine on. Set in MANUAL mode.
4. Set the Temperature Setpoint to the various settings specified on the
INSPECTION FORM (section 7.4, p. 33), wait until the IN-TEMP LED
comes on and the water temperature stabilizes, then record the
temperature of the mercury thermometer and that shown on the
display. Verify that the recorded values are within limits outlined on
INSPECTION FORM, item i.
j) Automatic Mode, Blanket Water Limit Check
To check the blanket water limit in AUTO mode, perform the
following:
1. Fill machine with distilled water until green band on float stem is
fully visible.
2. Connect the test setup as shown in figure 13 (p. 72).
3. Connect a resistance of 1355 ohms to the patient probe jack to
simulate a 37°C patient temperature.
4. Turn machine on and place in AUTO mode with setpoint of 40°C.
5. Verify that the mercury thermometer does not exceed 42°C.
7.3 FUNCTIONAL CHECK &
SAFETY INSPECTION
(continued)
FUNCTIONAL CHECK &
SAFETY INSPECTION
23
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
k) High Temperature Backup Thermostat Trip Temperatures
The following procedure describes two different approaches for
measuring the trip points (actuation temperatures) of the machine’s high
temperature backup thermostats. Steps 1-15, pp. 25-26, should be
followed when a Gaymar MT590 Test Tool is available. For those facilities
not having access to an MT590, follow steps 1A-20A, pp. 27-28.
7.3 FUNCTIONAL CHECK &
SAFETY INSPECTION
(continued)
COMPRESSOR
COLD SOL.
HOT SOL.
PUMP
HEATER
J1
S2
BYPASS
NORMAL
R.F.U. CIRCUITSELECT
HIGH TEMPERATURE
BACKUPTHERMOSTAT S
P/N 07713-000
TEST
PROBE
PATIENT
S3
®
A
B
FROM MT590 TEST TOOL
TO J1 ON POWER SUPPLY
BOARD IN HEAD
TO J1 ON
MT590 TEST TOOL
PATIENT PROBE
SIMULATOR
37°C
32°C
Figure 4—MT590 Test Tool
FUNCTIONAL CHECK &
SAFETY INSPECTION
24
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
7.3 FUNCTIONAL CHECK &
SAFETY INSPECTION
(continued)
FUNCTIONAL CHECK &
SAFETY INSPECTION
WARNING
k) High Temperature Backup Thermostat Trip Temperatures
[MT590 Test Tool Procedure]
• Changes to the wiring of the high temperature backup
thermostats can defeat their operation. To verify thermostat
operation, perform the Thermostat Verification Test described
in section 7.3, item l, p. 29 after performing the following
test procedure.
• After performing the following test procedure, verify that
the MT590 Test Tool or any installed shorting jumpers have
been removed before returning the machine to patient use.
Failure to do the above may result in death or serious
injury.
To measure trip points of the high temperature backup thermostats with
an MT590 Test Tool, perform the following steps 1-15:
1. Fill machine with distilled water until green band on float stem is fully
visible.
2. Unplug the power cord.
3. Connect the test setup as shown in figure 13, p. 72.
4. Connect MT590 Test Tool as shown in figure 4. Connect P7 (base) to
J1 (MT590). Connect 12 pin cable (MT590) to J1 (head, power supply
board). Plug machine in. Insure the S2 and S3 toggle switches are in
the NORMAL position.
5. Place the machine in service mode 3. Refer to section 8.1, SERVICE
MODES (pp. 34-35) for instructions on how to access service modes.
6. To insure the correct measurement of thermostat trip points, run
machine for 5 minutes in service mode 3 (see Table 3, service mode 3,
p. 37) after the blanket water temperature has reached 105.8°F (41°C)
for models MTA5900 or MTA5901, and 107.6°F (42°C) for model
MTA5942. This allows the inside of the machine to achieve normal
operating temperature. (Bottom wraparound cover must be on
machine during this test.)
7. Enter service mode 4 (see section 8.1, p. 34) from service mode 3.
Mode 4 will cause the machine to heat up until one of the safety
thermostats trip.
8. Monitor the blanket water temperature. When the ALERT and
REMOVE FROM USE NOW / MACHINE SHUTDOWN LED’s light and
the audible alarm sounds, the temperature on the mercury
thermometer should be within the high temperature limits range. (See
Table 1 below for high temperature limits with corresponding model
number of your machine.) When the thermostat trips, record the
thermometer temperature on the INSPECTION FORM (p. 33).
(If this is the second thermostat tested, proceed to step 12.
Otherwise, proceed with step 9.)
MTA5942 MTA5900 MTA5901
High Temperature Limits
Fixed (S2) & (S3)
111.2°F (44°C)
to
120.2°F (49°C)
109.4°F (43°C)
to
120.2°F (49°C)
109.4°F (43°C)
to
120.2°F (49°C)
Table 1—High Temperature Limits
25
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
k) High Temperature Backup Thermostat Trip Temperatures
[MT590 Test Tool Procedure, cont'd.]
9. An LED should be lit on the face of the MT590 Test Tool to
indicate an open S2 or S3 thermostat. If both LED’s are lit, proceed
to step 12. (Both thermostats have tripped at the same
temperature. This is allowable so long as the water at the TPT9 was
within the high temperature limits range. (See Table 1, p. 25, for
high temperature limits with corresponding model number of your
machine.) Otherwise, toggle the corresponding switch S2 or S3 to
the bypass position for whichever LED was lit.
10. Turn machine off.
11. Place machine in service mode 3. If machine still indicates REMOVE
FROM USE NOW / MACHINE SHUTDOWN, then the other thermostat
has tripped at the same temperature. This is allowable so long as the
water temperature at the TPT9 was within the high temperature limits
range. (See Table 1, p. 25 for high temperature limits with
corresponding model number of your machine.) Verify the non-
bypassed LED is lit. Record the temperature. Proceed to step 12.
If the unit enters service mode 3 with no REMOVE FROM USE NOW /
MACHINE SHUTDOWN alarm, then repeat steps 6 through 8 to check
the other thermostat
12. Place both switches S2 and S3 in the bypass position. Turn the machine
off, then turn the machine on and select MANUAL mode. Allow
machine to run for approximately 1 minute. This will circulate cold
water from the reservoir past the thermostats, causing them to reset.
13. Return switches S2 and S3 to the normal position. If unit continues to
be in alarm condition, repeat step 12.
14. While the machine is running in MANUAL mode, place the RFU
CIRCUIT SELECT A-B switch in the “A” position and toggle the TEST
switch. The machine should shut down, blank the displays, light the
REMOVE FROM USE NOW / MACHINE SHUTDOWN LED, flash the
ALERT LED and toggle the audible alarm. Turn the machine off, then
restart the machine in the MANUAL mode.
Repeat the above procedure with the RFU CIRCUIT SELECT switch in
the “B” position.
This step will verify that both (redundant) RFU circuits are
functioning.
15. Turn machine off and unplug the power cord. Disconnect
MT590 Test Tool from wire harness and reassemble machine.
Verify that the MT590 Test Tool or any installed shorting
jumpers have been removed before returning the machine to
patient use.
Failure to do so may result in death or serious injury.
7.3 FUNCTIONAL CHECK &
SAFETY INSPECTION
(continued)
FUNCTIONAL CHECK &
SAFETY INSPECTION
WARNING
26
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
k) High Temperature Backup Thermostat Trip Temperatures
[Alternate Shorting Jumper Procedure]
To measure trip points of the high temperature backup thermostats if
you do not have access to an MT590 Test Tool, perform the following
steps 1A-20A. (If you have access to an MT590, follow steps 1-15 on the
preceding pages.)
• Changes to the wiring of the high temperature backup thermo-
stats can defeat their operation. To verify thermostat operation,
perform the Thermostat Verification Test described in section 7.3,
item l, p. 29 after performing the following test procedure.
• After performing the following test procedure, verify that the
MT590 Test Tool or any installed shorting jumpers have been
removed before returning the machine to patient use.
Failure to do the above may result in death or serious
injury.
7.3 FUNCTIONAL CHECK &
SAFETY INSPECTION
(continued)
FUNCTIONAL CHECK &
SAFETY INSPECTION
WARNING
27
SERVICE MANUAL
Medi-Therm II
1A. Fill machine with distilled water until green band on float stem is
fully visible.
2A. Unplug the power cord.
3A. Remove wraparound (see figure 14, p. 73). Flex side panels of
wraparound out slightly to clear foam.
4A. Remove plastic cover from wiring terminal block TB1.
(See figure 14 for TB1 location.)
5A. Replace wraparound cover. Do not reinstall screws at this time.
6A. Connect test setup as shown in figure 13, p. 72.
7A. Plug the machine in.
8A. Place the machine in service mode 3. Refer to section 8.1, SERVICE
MODES (pp. 34-35) for instructions on how to access service modes.
9A. To insure the correct measurement of thermostat trip point
(because the wraparound was removed), run machine for 15
minutes after the blanket water temperature has reached 105.8°F
(41°C) for models MTA5900 or MTA5901, and 107.6°F (42°C) for
model MTA5942. This allows the inside of the machine to achieve
normal operating temperature.
10A. Enter service mode 4 (see section 8.1, p. 34) from service mode 3.
Mode 4 will cause the machine to heat up until one of the safety
thermostats trip.
11A. Monitor the blanket water temperature. When the ALERT and
REMOVE FROM USE NOW / MACHINE SHUTDOWN LED’s light and
the audible alarm sounds, the temperature on the mercury
thermometer should be within the high temperature limits range. (See
Table 1, p. 25, for high temperature limits with corresponding model
number of your machine.) This indicates that one of the safety
thermostats has tripped. Record the thermometer temperature at
which the thermostat tripped on the INSPECTION FORM.
www.gaymar.com P/N 10187-000 7/98
k) High Temperature Backup Thermostat Trip Temperatures
[Alternate Shorting Jumper Procedure, cont’d.]
NOTE: If this is the second time the thermostat has tripped
(i.e., if you have previously completed steps 12A to 18A),
proceed to step 19A. Otherwise, proceed to step 12A.
12A. Turn the machine off and unplug the power cord.
Disconnect hoses.
13A. Remove wraparound cover from machine.
14A. Place a shorting jumper across terminals 7 and 9 of TB1. Reconnect
the machine to the wall outlet, turn it on, and press the MANUAL
mode button. If the unit indicates REMOVE FROM USE NOW /
MACHINE SHUTDOWN proceed to step 15A. If the unit enters
MANUAL mode with no REMOVE FROM USE NOW / MACHINE
SHUTDOWN alarm, then proceed to step 17A.
15A. Turn the machine off and unplug the power cord. Remove
shorting jumper from terminals 7 and 9 of TB1 and reconnect across
terminals 7 and 10.
16A. Plug machine in and turn it on. Press the MANUAL mode button. If the
machine still indicates a REMOVE FROM USE NOW / MACHINE
SHUTDOWN alarm, then both thermostats have tripped at the same
temperature. This is allowable so long as the water temperature at
the TPT9 was within the high temperature limits range. (See Table 1,
p. 25 for high temperature limits with corresponding model number
of your machine.) If both thermostats have tripped, proceed to step
19A. If the unit enters MANUAL mode with no REMOVE FROM USE
NOW / MACHINE SHUTDOWN alarm, then proceed to step 17A.
17A. Turn the machine off and unplug the power cord. Replace
wraparound cover. Reconnect hoses from test setup to machine (see
figure 13, p. 72).
18A. Repeat steps 7A through 11A.
19A. Turn the machine off and unplug the power cord. Disconnect
supply hose from TPT9 and allow water to gravity drain into a
container for approximately one minute. This will circulate cold water
from the reservoir past the thermostats, causing them to reset. Do
not install a second shorting jumper. Reconnect supply hose to TPT9
and return drained water to machine reservoir.
20A. Remove wraparound cover from machine. Remove shorting jumper.
Replace plastic terminal block cover. Replace wraparound cover and
reinstall screws.
Verify that the MT590 Test Tool or any installed shorting
jumpers have been removed before returning the machine to
patient use.
Failure to do so may result in death or serious injury.
7.3 FUNCTIONAL CHECK &
SAFETY INSPECTION
(continued)
FUNCTIONAL CHECK &
SAFETY INSPECTION
WARNING
28
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
l) Thermostat Verification Test
Verify that the high temperature backup thermostats
independently shut down the machine.
Incorrect operation of these thermostats may result in
death or serious injury.
1. Fill machine with distilled water until green band on float stem is
fully visible.
2. Unplug the power cord.
3. Remove wraparound (see figure 14, p. 73). Flex side panels of
wraparound out slightly to clear foam.
4. Remove plastic cover from thermostats (see figs. 17 & 17A, p. 77
for thermostat location). (On some models only.)
5. Carefully disconnect the yellow wire from the top thermostat (S3)
by pulling the connector off the terminal along the same angle as
the terminal (see figures 17 & 17A, p. 77).
6. Plug in the machine and turn it on.
7. Select MANUAL mode.
8. Observe that the machine indicates REMOVE FROM USE NOW /
MACHINE SHUTDOWN.
9. Turn the machine off and unplug the power cord.
10. Reconnect the yellow wire to S3.
11. Carefully disconnect the yellow wire from the lower thermostat
(S2) by pulling the connector off the terminal along the same angle
as the terminal.
12. Plug the machine in and turn it on.
13. Select MANUAL mode.
14. Observe that the machine indicates REMOVE FROM USE NOW /
MACHINE SHUTDOWN.
15. Turn the machine off and unplug the power cord.
16. Reconnect the yellow wire to S2.
17. Replace the plastic cover over the thermostats.
18. Replace wraparound and reinstall screws.
7.3 FUNCTIONAL CHECK &
SAFETY INSPECTION
(continued)
FUNCTIONAL CHECK &
SAFETY INSPECTION
WARNING
29
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
m) Patient Temperature Display Test
To check the patient temperature display, perform the following:
1. Fill machine with distilled water until green band on float stem is
fully visible.
2. Connect a resistance of 1355 ohms to the patient probe jack, to
simulate a 98.6°F (37°C) patient temperature.
3. Turn machine on and set it in the MANUAL mode.
4. PATIENT Temperature Display should indicate 98.6°F (37°C)
± 0.5°F (0.3°C). Record appropriate value on INSPECTION FORM.
5. Connect a resistance of 1667 ohms to the patient probe jack to
simulate an 89.6°F (32°C) patient temperature.
6. PATIENT temperature display should indicate 89.6°F (32°C)
± 0.5°F (0.3°C). Record appropriate value on INSPECTION FORM.
NOTE: The CHECK PATIENT PROBE alarm may flash on
during step 6 if the display indicates less than 89.6°F
(32.0°C). This condition is considered normal and
allowable.
n) Low Temperature Backup Thermostat (S1) (Optional)
The low temperature backup thermostat is a fixed trip point
thermostat to limit low temperatures between 26.6°F (-3.0°C) and
36.5°F (+2.5°C).
It is not necessary to test the trip point as part of this
functional test. The function of the thermostat is to protect
the machinery from freezing. It is not a patient safety-related
device.
If there is reason to test this thermostat, perform the following:
1. Drain machine of water as follows:
a. Connect a DBK9 connector hose to the SUPPLY fitting on
machine.
b. Turn machine on and select MANUAL mode. Allow machine to
pump water out until ADD WATER light comes on. Turn
machine off and allow unit to gravity drain until empty.
c. Disconnect DBK9.
2. Unplug the power cord.
3. Add eight (8) quarts (7.6 liters) of water and two (2) quarts (1.9
liters) of alcohol to reservoir.
4. Connect the test setup shown in figure 13, p. 72.
5. Plug machine in and place it in service mode 2. Refer to section
8.1, SERVICE MODES (pp. 34-35) for instructions on how to
access service modes.
NOTE: In service mode 2, the compressor, pump, and cold
solenoid are activated. No temperature measurement
or other control is performed by the machine in this
mode.
7.3 FUNCTIONAL CHECK &
SAFETY INSPECTION
(continued)
FUNCTIONAL CHECK &
SAFETY INSPECTION
30
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
n) Low Temperature Backup Thermostat (S1) (cont’d.)
6. When the contacts of S1 open up, the audible alarm, the
REMOVE FROM USE NOW / MACHINE SHUTDOWN LED, and the
ALERT LED will come on. The mercury thermometer should read
between 26.6°F (-3.0°C) and 36.5°F (+2.5°C) at this point.
7. Turn machine off. Allow it to warm up to reset thermostat.
8. Drain machine of water and alcohol mixture as in step 1 above.
9. Refill with distilled water until the green band on the float stem is
fully visible.
o) Grounding Resistance
Use an ohmmeter to measure the resistance between the grounding
pin on the line cord attachment plug and an exposed metal point on
the chassis. The value should be less than 0.5 ohms.
p) Current Leakage, CHASSIS
Measure the maximum current leakage between the chassis and the
ground in all operating configurations (heating, cooling, compressor ON,
compressor OFF, normal and reverse polarity with the machine
grounded and ungrounded). The current leakage should not exceed the
following:
Condition Current Leakage
Machine grounded 10 microamps
Machine ungrounded 100 microamps
Current Leakage, PATIENT PROBE
It is first necessary to prepare a patient probe by wrapping it tightly
along its entire length with metal foil. Then measure current leakage at
the foil for all combinations: grounded, ungrounded, normal polarity, and
reversed polarity. The current leakage should not exceed 50 microamps.
NOTE: If additional information is required, refer to AAMI American National
Standard, Safe Current Limits for Electromedical Apparatus or contact
Gaymar's Technical Service Department.
q) Reset the RFU Code (not applicable to machines
containing Version 1.0 software)
The Medi-Therm II machine will retain the previously stored code.
Before returning a machine to service, reset the RFU code to zero so
that a previous code is not held in memory.
To reset the RFU code to zero:
1. Place the machine in service mode 1 (see section 8.1, p. 34).
2. Press the TEST LIGHTS button on the control panel.
The RFU code is reset when the number on the blanket display shows “0”.
7.3 FUNCTIONAL CHECK &
SAFETY INSPECTION
(continued)
FUNCTIONAL CHECK &
SAFETY INSPECTION
31
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
This completes the recommended functional test and preventive maintenance
procedures for the Gaymar Medi-Therm II.
If a machine passes all the requirements of paragraphs “a” through “q”, the
machine should be considered operational and suitable for return to service.
Verify that the MT590 Test Tool or any installed shorting jumpers
have been removed before returning the Medi-Therm II to service.
Failure to do so may result in death or serious injury.
7.3 FUNCTIONAL CHECK &
SAFETY INSPECTION
(continued)
FUNCTIONAL CHECK &
SAFETY INSPECTION
WARNING
32
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
7.4 INSPECTION FORM
INSPECTION FORM
Medi-Therm II Hyper/Hypothermia
Functional Check / Inspection Form *
Location ____________________________________________________ Serial number ___________________________________
Item OK? (Y/N) Action needed
Action Taken
(Date / Initials)
a. Condition of chassis
b. Condition of attachment plug
c. Line cord and strain reliefs
d. Circuit breaker
e. Condition of lights and alarm
f. Flow: MTA5942/MTA5900 MTA5901
1. Greater than . . .
[HEATING]
16 gph
(60.6 l/hr)
12 gph
(45.4 l/hr)
2. Greater than . . .
[COOLING]
16 gph
(60.6 l/hr)
12 gph
(45.4 l/hr)
3. Flow switch activation
g. Level switch activation
h. Cold water reservoir controller: 37.4°F (3°C) to 42.8°F (6°C)
i. Blanket water temperature controller and display test:
Temperature
Control
Setpoint
Display
Reading
Mercury
Thermometer
Reading
50°F (10°C)
77°F (25°C)
105.8°F (41°C)
Display readings within 1.8°F (1°C) of temperature setpoint
Mercury thermometer reading within 1.8°F (1°C) of temperature setpoint
j. Automatic mode, Blanket water limit
k1. MTA5900/MTA5901
S2: High temperature backup thermostat: 109.4°F (43°C) to 120.2°F (49°C)
S3: High temperature backup thermostat: 109.4°F (43°C) to 120.2°F (49°C)
k2. MTA5942 ONLY
S2: High temperature backup thermostat: 111.2°F (44°C) to 120.2°F (49°C)
S3: High temperature backup thermostat: 111.2°F (44°C) to 120.2°F (49°C)
l. Thermostat verification test: S2/S3
m. Patient temperature display test:
Probe
Resistance
(ohms)
Patient
Temperature
Display
1355 98.6°F ± 0.5°F
(37°C ± 0.3°C)
1667 89.6°F ± 0.5°F
(32°C ± 0.3°C)
n. Low temperature backup thermostat (S1): 26.6°F (-3.0°C) to 36.5°F (+2.5°C)
o. Ground resistance less than 0.5 ohms
p. Current leakage:
Chassis (grounded) ............ 10 microamps max.
Chassis (ungrounded) .......... 100 microamps max.
PatientProbe................. 50 microamps max.
q. Reset of RFU code **
* Complete entire Functional Check / Inspection Form prior to troubleshooting unit.
** Not applicable to machines containing Version 1.0 software (see section 4.1).
33
SERVICE MANUAL
Medi-Therm II
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Some troubleshooting and functional checks may be aided by using the
Medi-Therm II machine’s service modes of operation.
All service modes are entered from service mode I by pressing the appropriate
digital control panel button within 10 seconds of entry into service mode 1. If no
button is pressed after service mode I is entered, the machine will reset itself to
standby mode after 10 seconds. See table 3 for a description of each mode.
To initiate service mode 1:
1. Turn machine off.
2. Remove the 6 screws holding the head to the base.
Wear a static control device connected to the chassis ground
to prevent electrostatic discharge. (See figure 5, p. 35.)
Electrostatic discharge can damage the control/display
board.
3. Lift the head, press and hold service button S3 on the low voltage
control/display board (figure 5), then turn the machine on.
In service mode 1, the machine will display the last RFU* code
(on the BLANKET display) and the software version (on the
PATIENT display). An RFU code may help to debug a machine
which has shut down due to a REMOVE FROM USE condition
(table 2).
Pressing the TEST LIGHTS button while in service mode I will
reset the RFU code to zero. Whenever returning a machine to
service, reset the RFU code to zero to avoid basing future
troubleshooting decisions on an old code.
NOTE: Early model machines containing version 1.0 software
do not have the RFU reset feature. If this feature is
desired, contact Gaymar's Technical Service
Department. An updated EPROM with this feature can
be purchased and installed in older model machines.
* RFU = REMOVE FROM USE NOW / MACHINE SHUTDOWN
CAUTION
8.0 TROUBLESHOOTING
& SERVICE MODES
8.1 SERVICE MODES
TROUBLESHOOTING
SERVICE MODES
34
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
8.1 SERVICE MODES (continued)
Table 2 - RFU
†
Codes
Figure 5—Initiating service mode 1
SERVICE MODES
SERVICE BUTTON S3
ON CONTROL/DISPLAY BOARD
RFU
Code
Description
Troubleshooting
Chart
*0 Reset code -- indicates no RFU condition recorded. None
1 Measured blanket or reservoir probe value is out of the range 32°F to 122°F
(0°C to 50°C).
Figure 6B
2, 3 Microprocessor system failure Figure 6C
4 Compensation resistor 1 (R12) is out of spec -- too high or open-circuited. Figure 6D
5 Compensation resistor 1 (R12) is out of spec -- too low or short-circuited. Figure 6D
6 Compensation resistor 2 (R13) is out of spec -- too high or open-circuited. Figure 6E
7 Compensation resistor 2 (R13) is out of spec -- too low or short-circuited. Figure 6E
8 Blanket probe measurement is out of spec -- possibly open or short-circuited. Figure 6F
9 Reservoir probe measurement is out of spec -- possibly open or short-circuited. Figure 6G
-- Microprocessor system failure -- CHECKSUM. Figure 6C
E Microprocessor system failure -- RAMTEST. Figure 6C
H Microprocessor received REMOVE FROM USE NOW / MACHINE SHUTDOWN
signal from the power supply board.
Figure 6H
*L Microprocessor system failure Figure 6C
†
RFU = REMOVE FROM USE NOW / MACHINE SHUTDOWN
* Not applicable to machines containing software version 1.0.
35
SERVICE MANUAL
Medi-Therm II
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Service Mode 1:
To access Press and hold S3 (see figure 5, p. 35) on the control/display board, then turn machine on.
Uses • Verification of software version level.
• Last RFU code indication and RFU code reset.
• Verification of proper watchdog functioning (U34).
• Entrance to other modes.
Description • Required for entrance to other modes.
• Patient display shows software version level.
• Blanket display shows RFU code.
• Pressing the TEST LIGHTS button will reset RFU code to zero.
• ALERT LED flashes.
• Leader lights flash.
• Setpoint display flashes “1”.
• 10 second duration. Machine resets to standby mode after 10 seconds if no buttons are pressed.
To exit Pressing the MANUAL, AUTO, or MONITOR buttons will cause entrance into other modes. If no further
action is taken by the user, the machine will reset itself to standby mode after approximately 10 seconds.
Service Mode 2:
To access Press MANUAL button while in service mode 1.
Uses To assist in testing trip point of S1 thermostat.
Description • Patient and blanket displays are blank.
• ALERT LED flashes.
• Leader lights flash.
• Setpoint display flashes “2”.
• Pump and compressor are turned on, and cold solenoid valve is opened.
• No temperature measurement is performed by the machine.
To exit Pressing any button except the MANUAL button will reset the machine to standby mode.
(Pressing the MANUAL button again will do nothing.)
(continued on next page)
Table 3 - Service Modes
SERVICE MODES
RFU = REMOVE FROM USE NOW / MACHINE SHUTDOWN
36
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
Service Mode 3:
To access Press AUTO button while in service mode 1.
Uses To prewarm the machine for testing of high temperature thermostat S2 and S3 trip points.
Description • Patient display is blank.
• ALERT LED flashes.
• Leader lights flash.
• Setpoint display flashes “3”.
• The blanket display shows the blanket water temperature in degrees Celsius or Fahrenheit
depending on choice made in last normal operating mode.*
• For models MTA5900 and MTA5901, the output water temperature is controlled to 105.8°F (41°C).
For model MTA5942, the output water temperature is controlled to 107.6°F (42°C).
To exit Pressing any button except the AUTO button or the °C/°F button will reset machine to standby mode.
(Pressing AUTO button again will do nothing.) Pressing the °C/°F button* will put the machine into
mode 4 from mode 3.
Service Mode 4:
To access Press °C/°F button* while in service mode 3.
Uses To test the trip points of the high temperature thermostats S2 and S3.
Description • Patient display is blank.
• ALERT LED flashes.
• Leader lights flash.
• Setpoint display flashes “4”.
• The blanket display shows the blanket water temperature in degrees Celsius or Fahrenheit,
depending on choice made in last normal operating mode.*
• For models MTA5900 and MTA5901, the output water temperature is controlled to 118.4°F (48°C ).
For model MTA5942, the output water temperature is controlled to 120.2°F (49°C) .
To exit Pressing any button except the °C/°F button will reset the machine to standby mode.
(Pressing the °C/°F button again will do nothing.)*
Service Mode 5:
To access Press MONITOR button while in service mode 1.
Uses • To verify reservoir probe reading.
• To assist troubleshooting cooling problems.
Description • Patient display shows the cold water reservoir temperature in degrees Celsius or Fahrenheit,
depending on what was selected during the last normal operating mode.*
• ALERT LED flashes.
• Leader lights flash.
• Setpoint display flashes “5”.
• The blanket display is blank.
• The pump is on and cold solenoid valve is opened.
• The compressor is controlled using normal control algorithms.
To exit Pressing any button except the MONITOR button will reset the machine to standby mode.
(Pressing the MONITOR button again will do nothing.)
Table 3 - Service Modes (continued)
SERVICE MODES
* Some models do not have the °C/°F feature. On the model MTA5901 machine, the SILENCE ALARM button replaces
the service mode function of the °C/°F button. Temperatures will be displayed only in degrees Celsius.
37
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
8.2 TROUBLESHOOTING CHARTS
Figure 6A—Accessing RFU codes
IMPORTANT
Whenever possible, perform the
FUNCTIONAL CHECK AND SAFETY
INSPECTION (see section 7.3) prior
to troubleshooting machine.
TROUBLESHOOTING CHARTS
38
SERVICE MANUAL
Medi-Therm II
See appropriate
REMOVE FROM
USE NOW /
MACHINE
SHUTDOWN
flow chart
Observe RFU
code
Enter Service
Mode 1--
See service mode
section
REMOVE FROM
USE NOW /
MACHINE SHUTDOWN
condition
www.gaymar.com P/N 10187-000 7/98
Figure 6B—RFU Code 1
TROUBLESHOOTING CHARTS
39
No
Yes
Suspect RT2.
Repair/replace.
Is RT2
actual
temperature between
32°F and 122°F
(0°C and 50°C)
?
Yes
No
Faulty signal lines
between
control/display board
and RT1.
Is it
between
811 and 7355
ohms
?
Yes
Yes
No
No
Suspect RT1.
Repair/replace.
No
Yes
Is RT1
actual
temperature between
32°F and 122°F
(0°C and 50°C)
?
Disconnect connector
P6 from J2 on the
power supply board and
measure resistance
between pins 2 and 9 of
connector P6.
Repair/replace
the
control/display board.
Suspect temperature
measurement
circuitry.
Is it
between
811 and 7355
ohms
?
Repair/replace
the
control/display board.
Suspect controller failure
caused RT1 or RT2 to read
an actual temperature outside
32°F to 122°F (0°C to 50°C)
range.
Faulty signal lines
between
control/display board
and RT2.
Is it
between
811 and 7355
ohms
?
No
Yes
Measure resistance
between pins 23 and 11
of J1 on back of
control/display board.
Disconnect connector P6
from J2 on the power
supply board and
measure resistance
between pins 3 and 5 of
connector P6 at base.
Is it
between
811 and 7355
ohms
?
Run machine. If RFU condition (RFU
code 1) reappears, unplug machine
and measure resistance between pins
10 and 11 of J1 on back of
control/display board.
Insure integrity of the control/display
board to power supply board
connections. Insure integrity of base
to power supply board connections.
RFU CODE 1
Measured values
from RT1 or RT2
are not within
32°F and 122°F
(0°C and 50°C).
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
Figure 6C—RFU Codes 2, 3, – , E, and L
TROUBLESHOOTING CHARTS
40
RFU Code 3
Conversion
Failure
Microprocessor
system failure.
Contact GAYMAR
Technical Services.
RFU Code L
RFU Code E
RAMTEST
Failure
RFU Code [–]
CHECKSUM
Failure
RFU Code 2
Conversion
Failure
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
Figure 6D—RFU Codes 4, 5
TROUBLESHOOTING CHARTS
41
RFU CODE 5
Compensation resistor 1
(R12 on
control/display board)
reading is too low
No
Yes
Repair/replace
the
control/display board.
Suspect
temperature
measurement
circuitry.
Is it
816 ohms
±0.1%
?
Replace R12.
Measure R12
resistance.
RFU CODE 4
Compensation resistor 1
(R12 on
control/display board)
reading is too high
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
Figure 6E—RFU Codes 6, 7
TROUBLESHOOTING CHARTS
42
RFU CODE 7
Compensation resistor 2
(R13 on control/display
board) reading is too low.
No
Yes
Repair/replace
the
control/display board.
Suspect
temperature
measurement
circuitry.
Is it
7320 ohms
±0.1%
?
Replace R13.
Measure R13
resistance.
RFU CODE 6
Compensation resistor 2
(R13 on
control/display board)
reading is too high.
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
Figure 6F—RFU Code 8
TROUBLESHOOTING CHARTS
43
Yes
No
Faulty signal lines
between
control/display
board and RT2.
Repair/replace
the
control/display board.
Repair/replace
the
control/display board
.
Suspect
temperature
measurement
circuitry.
Is it
between
811 and 7355
ohms
?
Run machine. If RFU condition
(RFU Code 8) reappears, unplug
machine and measure resistance
between pins 10 and 11 of J1 on
back of control/display board.
Insure integrity of control/display
board to power supply board
connections. Insure integrity of
base to power supply board
connections.
Yes
Yes
No
No
Suspect controller failure
caused RT2 to actually
read outside
32°F to 122°F
(0°C to 50°C) range
(811 to 7355 ohms).
Is RT2
temperature
between 32°F and
122°F (0°C and
50°C)?
Suspect RT2.
Repair/replace.
Is it
between
811 and 7355
ohms
?
Measure
resistance between
pins 3 and 5 of
connector P6.
Disconnect
connector P6 from
J2 on power supply
board.
RFU CODE 8
Blanket probe
reading faulty
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
Figure 6G—RFU Code 9
TROUBLESHOOTING CHARTS
44
Yes
No
Faulty signal lines
between
control/display
board and RT1.
Repair/replace
the
control/display board.
Repair/replace
the
control/display
board.
Suspect
temperature
measurement
circuitry.
Is it
between
811 and 7355
ohms
?
Run machine. If RFU condition
(RFU Code 9) reappears, unplug
machine and measure resistance
between pins 23 and 11 of J1 on
back of control/display board.
Insure integrity of control/display
board to power supply board
connections. Insure integrity of
base to power supply board
connections.
Yes
Yes
No
No
Suspect controller failure
caused RT1 to actually
read outside
32°F to 122°F
(0°C to 50°C) range
(811 to 7355 ohms).
Is RT1
temperature
between
32°F and 122°F
(0°C and 50°C)
?
Suspect RT1.
Repair/replace.
Is it
between
811 and 7355
ohms
?
Measure
resistance between
pins 2 and 9 of
connector P6.
Disconnect
connector P6 from
J2 on power supply
board.
RFU CODE 9
Reservoir probe
reading faulty
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
TROUBLESHOOTING CHARTS
45
SERVICE MANUAL
Medi-Therm II
[This page has been intentionally left blank.]
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
TROUBLESHOOTING CHARTS
See
"CHECK WATER
FLOW Alert is On"
(figure 6I)
Yes
No
Is
CHECK WATER
FLOW
alert on?
Repair/replace
power board.
No
Yes
No
Yes
Yes
No
A thermostat is
open. Determine
which.
Unit may have
cooled/warmed
sufficiently.
Thermostats are
closed
Suspect REMOVE
FROM USE
NOW/MACHINE
SHUTDOWN
circuitry
Replace
thermostat.
Is
resistance
0?
Is
S2 or S3
thermostat
out of spec
?
Power down unit.
Measure ohms
across TB1
terminals 10 and 8.
Test S2, S3 as
indicated in High
Temperature
Thermostat
Function Test.
Does
RFU condition
reappear?
Power up unit and
press AUTO or
MANUAL.
Power down unit.
Connect test setup as
shown in figure 13.
RFU CODE H
Microprocessor
received shutdown
signal from base.
Operate unit in
MANUAL mode
with setpoint
temperature equal
to 105.8°F (41°C)
for models
MTA5900 and
MTA5901, and to
107.6°F (42°C) for
model MTA5942.
Figure 6H—RFU Code H, Page 1 of 2
46
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
No
Yes
Yes
No
No
Is S1
thermostat
out of spec
?
Test S1
as indicated in
Low Temperature
Thermostat
Function Test.
Yes
No
Yes
No
No
Yes
Yes
Yes
No
Yes
No
Replace
thermostat.
Replace S1
Does
TPT9 read
less than 37.4°F
(3°C) ?
Is
S2 or S3
thermostat out
of spec
?
Does
RFU condition
reappear?
Does
TPT9 read
less than 37.4°F
(3°C)?
Test S2, S3 as
indicated in High
Temperature
Thermostat
Function Test.
Operate unit in
MANUAL mode
with setpoint
temperature equal
to 39.2°F (4°C).
Does
RFU condition
reappear?
Possible faulty control system
or temperature measurement
circuitry. Call Gaymar
Technical Services.
Allow unit to cool
to room
temperature or
until
thermostat closes.
Allow unit to warm
to room
temperature or
until thermostat
closes.
Operate unit in
MANUAL mode
with setpoint
temperature equal
to 39.2°F (4°C).
Does
RFU condition
reappear?
Is it S2 or S3?
S1 is open
TROUBLESHOOTING CHARTS
Figure 6H—RFU Code H, Page 2 of 2
47
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
TROUBLESHOOTING CHARTS
*
*
**
Yes
No
Connect
hoses
properly.
Are
hoses
connected properly
(one to SUPPLY, one
to RETURN)
?
Disconnect
cold solenoid SV1.
Measure coil
resistance for
short.
No
Yes
No
Yes
No
No
Yes
Yes
Yes
Adjust setpoint
to insure HEAT
LED is on
Check/suspect
solenoids.
Second, suspect
control/display
board.
Repair/replace.
Test switch contact
opening before
reinstalling.
First, suspect
flow switch S5.
Repair/replace.
See
"PUMP
MOTOR
NOT
RUNNING"
(figure 6J).
Is
pump motor
running
?
Is flow OK?
See section 4.1
for minimum
values.
Test flow rate with
machine heating
and cooling.
Connect
test setup
as shown
in figure 13.
Is a steel object
attracted to center top of
the valve?
YesNo
Yes
No
Yes
No
No
No
Yes
Is pin
11 ref to pin
10 of U51
0 VDC?
Suspect
control/display
board.
Repair/replace.
Suspect
board-to-board
connection.
Repair.
Is
optocoupler U8
input pulled
low?
Suspect
base-to-power
supply board
connection.
Repair.
Line
voltage at
output of
Q8?
Line
voltage at
terminals 1
and 3 of
TB1?
Check
cold solenoid SV1
(it should be
energized).
Repair/replace
hot solenoid SV2.
Is
SV2 coil
energized
?
Adjust setpoint
to insure COOL
LED is on
Check
hot solenoid SV2
(it should be
energized).
Correct
occlusion.
Are
blankets, hoses
or connectors
pinched or
occluded
?
Replace
blankets,
hoses.
Are
blankets,
hoses excessively
dirty
?
CHECK WATER
FLOW
alert is on.
Figure 6I—Check Water Flow Alert is On, Page 1 of 2
48
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
TROUBLESHOOTING CHARTS
**
Is a steel object
attracted to center top
of the valve?
**
Yes
Replace
impeller.
No
Is
impeller
broken or
cracked
?
Yes
No
No
Yes
Repair/replace
hot solenoid SV2.
Suspect
Q8 or U7.
Repair/replace
power supply
board.
Assume
Q8 triac
is also damaged.
Repair/replace
power supply
board.
Is
hot solenoid
SV2 coil
shorted
?
Disconnect
hot solenoid SV2.
Measure coil
resistance for short.
Is
cold solenoid
SV1 coil
shorted
?
Suspect
Q9 or U8.
Repair/replace
power supply
Assume
Q9 triac is
also damaged.
Repair/replace
power supply board.
Repair/replace
cold solenoid
SV1.
Yes Yes
NoNoNo
YesYes
No
Yes
Call
GAYMAR
Technical
Service
No
Repair/replace cold
solenoid SV1.
Suspect
control/display
board.
Repair/replace.
Is SV1 coil
energized?
Is pin 9
ref to pin 10
of U51
0 VDC?
Suspect
board-to-board
connection.
Repair.
Is
optocoupler
pulled
low?
Line
voltage at
output of
Q8?
Suspect
base-to-power
supply board
connection.
Line
voltage at
terminals 2
and 3 of
TB1?
U7 input
Figure 6I—Check Water Flow Alert is On, Page 2 of 2
49
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
TROUBLESHOOTING CHARTS
No
Yes
Assume Q4 triac is
also damaged.
Repair/replace
power supply
board.
Replace
pump.
Suspect Q4 or U2.
Repair/replace
power supply
board.
Is
pump
winding
shorted
?
Yes
Yes
Yes
Yes
No
No
No
No
Suspect
control/display
board.
Repair/replace.
Suspect
board-to-board
connection.
Repair.
Is pin
8 ref to pin
10 of U51
0 VDC?
Disconnect pump and
measure resistance for
short. (It should be
approximately 10
ohms.)
Is
optocoupler U2
input pulled
low?
Suspect
base-to-power
supply board
connection.
Repair.
Line
voltage at
output of
Q4?
Repair/
replace
pump.
Line
voltage at
terminals 6
and 8 of
TB1?
Verify unit is in
AUTO or MANUAL
modes.
PUMP MOTOR
NOT RUNNING
Figure 6J—Pump Motor Not Running
50
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
51
TROUBLESHOOTING CHARTS
[This page has been intentionally left blank.]
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
TROUBLESHOOTING CHARTS
Is a steel object
attracted to center top of
the valve?
*
*
**
Yes
Connect
test setup
as shown
in figure 13.
No
Yes
Assume Q8 triac
is also damaged.
Repair/replace
power supply
board.
Repair/replace
hot solenoid
SV2.
Suspect Q8 or
U7.
Repair/replace
power supply
board.
Is
hot solenoid
coil SV2
shorted
?
If thermometer in
TPT9 contradicts
this, suspect RT2.
No
Is
blanket display
within 1°C of
setpoint
?
No
Yes
No
No
Yes
Yes
No
Yes
No
Yes
No
Yes
Suspect
board-to-board
connection.
Repair.
Suspect
control/display
board.
Repair/replace.
Suspect Q9 or U8.
Repair or replace
power supply
board.
Is pin 9
ref to pin 10
of U51
0 VDC?
Suspect
board-to-board
connection.
Repair.
Suspect
base-to-power
supply board
connection.
Repair.
Is
optocoupler U7
input pulled
low?
Disconnect hot
solenoid SV2.
Measure coil
resistance for
short.
Repair/replace
hot solenoid
SV2.
Line
voltage at output
of Q8?
Suspect
base-to-power
supply board
connection.
Repair.
Is SV2 coil
energized?
Line
voltage at
terminals 2
and 3 of
TB1?
Check
hot solenoid SV2
(it should be on).
See
"PUMP MOTOR
NOT RUNNING"
(figure 6J)
Is
pump
running
?
Check pump
(it should be
running)
Select MANUAL mode.
Adjust setpoint to 41°C.
Allow machine time to
heat (30 minutes max.)
BLANKET WON’T
HEAT IN AUTOOR
MANUAL MODE
**
Figure 6K—Blanket Won't Heat in Auto or Manual Mode, Page 1 of 2
52
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
TROUBLESHOOTING CHARTS
*
*
*
*
No
Yes
Is it
opened or
shorted
?
Measure resistance
of heater. Refer to
power supply board
schematic (fig. 21)
for heater
resistance.
NoYes
Yes
No
Yes
No
No
Yes
No Yes
Yes
No
Yes
Yes
No
No
No
Yes
Is pin 7
ref to pin 10
of U51
0 VDC?
Suspect
control/display
board.
Repair/replace.
Suspect
board-to-board
connection.
Repair.
Suspect
control/display
board.
Repair/replace.
Disassemble
solenoids. Clean,
inspect seats,
repair/replace.
Suspect Q3 or U1.
Repair/replace
power supply
board.
Is
optocoupler
U1 input
low?
Is pin 11
ref to pin 10
of U51
0 VDC?
Replace
heater.
Suspect cold
solenoid SV1 may be
stuck open, or hot
solenoid SV2 may be
stuck closed.
Suspect
base-to-power
supply board
connection.
Repair.
Line
voltage at
output of
Q3?
Is
optocoupler U8
input pulled
low?
Line
voltage at
terminals 11
and 8 of
TB1?
Line
voltage at output
of Q9?
Check heater
(it should be on)
Line
voltage at
terminals 1
and 3 of
TB1?
Check
cold solenoid SV1
(it should be off).
See
"CHECK WATER
FLOW alert is on"
(figure 6I)
Is
there
adequate
flow?
pulled too
Figure 6K—Blanket Won't Heat in Auto or Manual Mode, Page 2 of 2
53
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
TROUBLESHOOTING CHARTS
Refrigeration
system
faulty
Is a steel object
attracted to center top of
the valve?
*
**
No
Yes
Connect test setup
as shown in figure
13 (but don’t use
the blanket).
No
No
Yes
Is
blanket display
within 1.8°F (1°C)
of setpoint
?
If thermometer
in TPT9
contradicts this,
suspect RT2.
Select MANUAL mode.
Adjust setpoint to
4°C (39.2°F).
Allow machine time
to cool.
(30 min. max.)
Yes
No
Yes
Yes
Is reservoir
temperature
42.8°F (6°C) or
below?
See
"CHECK WATER
FLOW alert is on"
(figure 6I)
See
"PUMP MOTOR
NOT RUNNING"
(figure 6J)
Dirty or restricted
refrigeration
condenser
Refrigeration unit
may have lost
its charge
No
Repair/replace
cold solenoid
SV1.
No
Yes
Yes
No
No
Check
hot solenoid SV2.
(it should be off).
Is SV1 coil
energized?
Is
there
adequate
flow
?
Is
pump
running
?
Check pump
(it should be
running)
Yes
Check heater
(it should be off)
Line
voltage at
terminals 2
TB1?
Will reservoir
temperature reach
42.8°F (6°C) or
below?
Is
compressor
on?
BLANKET WILL
NOT COOL
See
"BLANKET WILL
NOT COOL"
(figure 6L,
page 3 of 3)
and 3 of
Figure 6L—Blanket Will Not Cool, Page 1 of 3
54
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
*
**
*
*
Assume Q8 is
also damaged.
Repair/replace
power supply
board.
Repair/replace
cold solenoid
SV1.
Yes
No
Suspect
Q9 or U8.
Repair/replace
power supply
board.
Is
cold solenoid
shorted
?
Yes
No
Check cold
solenoid SV1
(it should
be on).
Yes
NoYes
No
Yes
No
Suspect
control/display
board.
Repair/replace.
Is pin 11
ref to pin 10
of U51
0 VDC?
Suspect
board-to-board
connection.
Repair.
Is
optocoupler U8
input pulled
low?
Disconnect
cold solenoid SV1.
Measure
coil resistance
for short.
Line
voltage at
output of
Q9?
Suspect
base-to-power
supply board
connection.
Repair.
Line
voltage at
terminals 1 and 3
of TB1?
No
Disassemble
solenoids.
Clean,
inspect seats,
repair/replace.
YesNo
No
Yes
No
Yes
Yes
Yes
No
Yes
Yes
No
No
Is pin
7 ref to pin
10 of U51
0 VDC?
Suspect
control/display
board.
Repair/replace.
Suspect
board-to-board
connection.
Repair.
Hot solenoid SV2
may be stuck
open or cold
solenoid SV1
stuck closed.
Suspect
Q3 or U1.
Repair/replace
power supply
board.
Is
optocoupler U1
input pulled
low?
Suspect
control/display
board.
Repair/replace.
Suspect
base-to-power
supply board
connection.
Repair.
Line
voltage at
output of
Q3?
Is pin 9
ref to pin 10
of U51
0 VDC?
Suspect
board-to-board
connection.
Repair.
Line
voltage at
terminals 11
TB1?
Is
optocoupler U7
input pulled
low?
Suspect
Q8 or U7.
Repair/replace
power supply
board.
Line
voltage at
output of
Q8?
Suspect
base-to-power
supply board
connection.
Repair.
and 8 of
SV1 coil
TROUBLESHOOTING CHARTS
Figure 6L—Blanket Will Not Cool, Page 2 of 3
55
NOTES:
* The line voltage measured should be the same as that measured across terminals 5
and 3 of TB1. (There may be residual voltage between terminals 2 and 3 or terminals
1 and 3 of TB1 when the circuitry is in the OFF state because of the solenoid valve
construction and circuit configuration. These are not considered line voltage.
** The solenoid coil can be tested with a multimeter set to the diode check function.
With the power off, measure the diode drop across the terminals of the solenoid coil
in both directions. There should be an open circuit in one direction and approximately
0.8V in the other. If not, the solenoid valve is bad and should be replaced.
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
TROUBLESHOOTING CHARTS
No
Yes
from
"BLANKET WILL
NOT COOL"
(figure 6L,
page 1 of 3)
Suspect
control/display
board.
Repair/replace.
Suspect
RT1.
Repair/replace.
Does
compressor
turn ON at 37.9°F
(3.3°C) and OFF at
Possible reservoir
probe (RT1)
problem. Enter
Service Mode 5.
No
No
Yes
Yes
No
Yes
No
Yes
Yes
No
Replace.
See power supply
board schematic.
Suspect
compressor
capacitor.
Suspect
compressor unit
thermal overload.
Suspect
compressor unit
starter relay.
Suspect
board-to-board
connection.
Repair.
Suspect
transistor Q12.
Repair/replace
power supply
board.
Suspect
base-to-power
supply board
connection.
Repair.
Suspect
relay K1.
Replace.
Is
pin 6 ref to
pin 10 of U51
0 VDC
?
Is
input signal
to transistor Q12
0 VDC
?
Is
12 volt signal
at transistor Q12
output
?
Is
12 VDC
across relay
K1 coil
?
Remove jumpers
(from pin 6 to pin 9
and from
pin 4 to pin 7).
Jumper
relay K1 contacts,
(pin 6 to pin 9,
and pin 4 to pin 7).
Is
compressor
on?
?
42.4°F (5.8°C)
Figure 6L—Blanket Will Not Cool, Page 3 of 3
56
SERVICE MANUAL
Medi-Therm II
REPAIR PROCEDURES
www.gaymar.com P/N 10187-000 7/98
Always perform the FUNCTIONAL CHECK AND SAFETY INSPECTION
(section 7.3) after making repairs and before returning the Medi-Therm
II machine to patient use.
Improper repair may result in death or serious injury,
equipment damage, or malfunction.
In addition to the following repair procedures, refer to the troubleshooting charts
in section 8.0, page 34, TROUBLESHOOTING AND SERVICE MODES.
• Equipment contains refrigerant under high pressure. Refer
servicing to a certified refrigeration service technician.
Improper repair procedures can result in serious
injury or damage the compressor unit.
• The refrigeration system contains rotating fan blades. Do not
operate with fan shroud removed.
Injury could result.
NOTE: Servicing and/or repair of the refrigeration system should be
performed in compliance with applicable federal, state, and local
regulations.
The Medi-Therm II refrigeration system uses either an R-12 (CFC-12) or an
R-134a (HFC-134a) refrigerant, but not both. To determine which type of
refrigerant is required by your system, refer to the nameplate located on the base
of the compressor. If you are still unable to identify the refrigerant type, contact
Gaymar’s Technical Service Department for assistance.
Refer to the appropriate section (9.1.1 or 9.1.2, p. 58) for charging
specifications.
9.0 REPAIR PROCEDURES
WARNING
WARNING
9.1 REFRIGERATION
SYSTEM
57
SERVICE MANUAL
Medi-Therm II
REPAIR PROCEDURES
www.gaymar.com P/N 10187-000 7/98
9.1.1 R-12 SYSTEMS
CAUTION
Do not attempt servicing the R-12 refrigeration unit unless you are certified in
R-12 refrigeration maintenance, repair, and reclaiming procedures.
Supply the following information to the refrigeration service technician:
Use only R-12 refrigerant and mineral oil when charging a
Medi-Therm II R-12 system.
Using other refrigerants or oils will damage the compressor.
• For refitting options approved for the Medi-Therm II, please contact
Gaymar’s Technical Service Department.
• The following values apply when the water temperature in the reservoir
reaches 40°F (4.4°C), with the wraparound off, at a 72°F (22.2°C) ambient:
R-12 charge ......................... 1 pound (approx.)
Low side pressure ............ 22 to 25 psi
High side pressure ........... 125 to 150 psi
• If recharging is required, most likely there is a leak in the system. Locate
and repair any leaks before recharging the unit.
• Replace the two service valve caps and two gage port caps after servicing
the refrigeration system.
After servicing the refrigeration unit, be sure to perform the FUNCTIONAL
CHECK AND SAFETY INSPECTION (see section 7.3).
Do not attempt servicing the R-134a refrigeration system unless you are
certified in R-134a refrigeration maintenance, repair, and reclaiming procedures.
Supply the following information to the refrigeration service technician:
• Use only R-134a refrigerant and polyol ester oil when
charging a Medi-Therm II R-134a system.
Using other refrigerants or oils will damage the
compressor.
• The Medi-Therm II R-134a system uses a polyol ester oil for
lubrication because conventional mineral oils do not provide
sufficient lubricity and miscibility. R-134a refrigerant and
polyol ester oil are highly susceptible to moisture
absorption (more so than R-12 and mineral oil).
It is important that proper system evacuation,
charging, and leak detection procedures be
employed. Do not leave the refrigeration system
open to ambient air when servicing. Moisture
absorption will result in reduced compressor life.
CAUTION
•
9.1.2 R-134a SYSTEMS
•
58
SERVICE MANUAL
Medi-Therm II
REPAIR PROCEDURES
www.gaymar.com P/N 10187-000 7/98
• The smaller molecular size of R-134a refrigerant allows it to leak from
smaller openings than R-12.
• Prior to charging the system, Gaymar recommends evacuating the system
to below 500 microns. Then, perform a vacuum decay test to assure there
is not a large differential between the system and the vacuum pump. After
5 minutes, the system should still be at 500 microns or below.
• For optimum performance, charge the R-134a system with 8.75
ounces of R-134a refrigerant. Make sure that the entire 8.75 ounce
charge is pulled from the gauge manifold and hoses into the system before
disconnecting.
• If it is necessary to check a unit’s charge, purge the refrigerant gauge manifold
and hoses with R-134a refrigerant from an external source before opening
the service valves to prevent affecting the unit’s charge.
In a properly charged unit, the low side refrigerant gauge pressure
should be approximately 15 to 25 psi; the high side pressure should be
approximately 115 to 135 psi, under the following conditions:
1. the unit’s wraparound is removed;
2. the ambient temperature is 72°F (22.2°C);
3. the unit is connected to a blanket, and the Medi-Therm II has
been set to 39.2°F (4°C) in manual mode;
4. the reservoir water temperature is 40°F (4.4°C); and,
5. the pressure check is performed with a gauge manifold connected
to the system with flexible hoses.
Upon completion of the pressure check, turn the unit off and allow
refrigerant in the manifold and hoses (especially the high side) to migrate
back into the unit before closing the service valves and disconnecting the
hoses. Warming the hose near the service valve with your hands for 2-3
minutes will ensure this.
• If recharging is required, most likely there is a leak in the system. Locate and
repair any leaks before recharging the unit.
• Replace the two service valve caps and two gage port caps after servicing the
refrigeration system.
After servicing the refrigeration unit, make sure to perform the FUNCTIONAL
CHECK AND SAFETY INSPECTION (see section 7.3).
9.1.2 R-134a SYSTEMS
(continued)
59
SERVICE MANUAL
Medi-Therm II
REPAIR PROCEDURES
www.gaymar.com P/N 10187-000 7/98
Wear a static control device connected to the chassis ground to
prevent electrostatic discharge. (See figure 5, p. 35.)
Electrostatic discharge can damage circuitry on PC boards.
The following procedures describe replacement of the power supply board. A
digital voltmeter is required.
Power Supply Board Removal (refer to figure 8, p. 67):
1. Unplug the power cord.
2. Disconnect the 26 conductor cable harness assembly from the power supply
board at J4.
3. Disconnect the three cable harness connectors P5, P6, and P7.
4. Remove the seven (7) board mounting screws.
5. Lift board out of head.
Power Supply Board Installation (refer to figure 8, p. 67):
1. Unplug the power cord.
2. Place the new power supply board in head.
3. Install seven (7) board mounting screws.
4. Connect the three cable harness connectors P5, P6, and P7 to J3, J2, and
J1 on the power supply board.
5. Perform a voltage check of the power supply board. Do not use the board
or connect it to the control/display board if the voltages are incorrect.
NOTE: To prevent an accidental short circuit, connect voltmeter
leads while the machine is off.
With the 26 conductor cable harness assembly disconnected from the
power supply board and the machine on, measure for the following
voltages at the following board locations (see figure 23, p. 84):
DVM DVM
Common + Lead Voltage
to Pin to Pin Reading
Q7 1 3 -12 ± 0.5V
Q6 2 3 +12 ± 0.5V
C16 – + +5.3 ± 0.3V
6. Turn machine off.
7. Connect the 26 conductor cable assembly.
8. Perform the FUNCTIONAL CHECK AND SAFETY INSPECTION (section 7.3)
CAUTION
9.2 REPLACING THE
POWER SUPPLY
BOARD
60
SERVICE MANUAL
Medi-Therm II
REPAIR PROCEDURES
www.gaymar.com P/N 10187-000 7/98
Wear a static control device connected to the chassis ground to
prevent electrostatic discharge. (See figure 5, p. 35.)
Electrostatic discharge can damage circuitry on PC boards.
Control/Display Board Removal (refer to figure 8, p. 67):
1. Unplug the power cord.
2. Disconnect the 26 conductor cable harness assembly from the control/
display board at J1.
3. Unfasten the patient probe assembly J1 from the head by removing the
hex nut and pull the assembly from its mounting hole.
4. Remove the six (6) board mounting screws and one standoff.
5. Push aside the ground harness and transformer cable and lift board
enough to gain access to the PC board.
6. Disconnect the digital control panel from the board at J4 and the patient
probe assembly from the board at J2.
NOTE: These connectors have locking tabs that must be pressed in order
to disengage them from the board.
Use care when disconnecting the digital control panel ribbon
from the control board.
Folding the ribbon cable may cause failure of the
control panel.
7. Lift board out of cover.
Control/Display Board Installation (refer to figure 8, p. 67):
1. Unplug the power cord.
2. Place the new control/display board in head.
3. Install the six (6) board mounting screws and one standoff as follows:
a. Install 3 board screws through the ground harness into the board.
NOTE: Insure that the corner screw also connects the ground
wire of the patient probe assembly to the board.
b. Install the standoff through the middle mounting hole on the board’s
edge. Insert 2 board screws through the transformer cable retaining
clips; mount one to the standoff, install the other directly through
the board.
c. Install the remaining board screw through the board.
9.3 REPLACING THE
CONTROL/DISPLAY
BOARD
CAUTION
CAUTION
61
SERVICE MANUAL
Medi-Therm II
REPAIR PROCEDURES
www.gaymar.com P/N 10187-000 7/98
4. Insert patient probe assembly into mounting hole and fasten with hex nut.
Insure patient probe assembly is oriented so that the bevelled corner of the
probe assembly is positioned as shown in figure 16, p. 76.
5. Connect the digital control panel plug P4 to the board at J4.
6. Connect the patient probe assembly plug P2 to the board at J2.
7. Perform a voltage check of the power supply board (see section 9.2, p.
60).
8. Connect the 26 conductor cable assembly from the power supply board.
9. Perform the FUNCTIONAL CHECK AND SAFETY INSPECTION (section 7.3).
To install a complete new cover:
1. Unplug the power cord.
2. Remove old top cover from machine by removing 6 screws underneath
top cover and disconnecting cables. See figure 14, p. 73.
3. Install new top cover.
4. Perform the FUNCTIONAL CHECK AND SAFETY INSPECTION (section 7.3).
To replace thermostat (see figures 15, 17, 17A and 18, pp. 74-75, 77, 79):
1. Unplug the power cord.
2. Remove wraparound from chassis.
3. Remove thermostat cover. (On certain models only.)
4. Disconnect spade lugs from thermostat terminals.
5. Carefully peel back insulating material.
6. Remove the two screws holding the thermostat. Remove the thermostat.
7. Apply thermal grease * (P/N 50040-000) to the underside of the
replacement thermostat to ensure proper operating temperature ranges.
* Recommended thermal greases:
• Silicone Heat Sink Compound
(Dow Corning; Midland, Michigan)
• Thermal Joint Compound Type 120-5
(Wakefield Engineering; Wakefield, Massachusetts)
Always use thermal grease on thermostats for MTA5900
series Medi-Therm II units.
Failure to use thermal grease could raise trip points
above the acceptable range.
8. Reconnect spade lugs to terminals. Refer to figures 17 & 17A, p. 77 to
ensure thermostat is connected correctly.
9.3 REPLACING THE
CONTROL/DISPLAY
BOARD
(continued)
9.4 REPLACING THE
TOP COVER
9.5 REPLACING
THERMOSTATS
CAUTION
62
SERVICE MANUAL
Medi-Therm II
REPAIR PROCEDURES
www.gaymar.com P/N 10187-000 7/98
Figure 7—Flow Switch
CAUTION
Do not bend or alter terminals.
Terminals may break. Also, bending may alter the
trip point range.
9. Mount thermostat, using existing screws.
10. Reapply insulating material.
11. Perform the FUNCTIONAL CHECK AND SAFETY INSPECTION (section 7.3).
To clean the flow switch (see figure 7 below and figure 15, pp. 74-75):
1. Remove nuts (item A) and remove assembly.
2. Loosen hose clamps (items B and C) and remove hoses.
3. Remove barbed adapters (item D). Remove plunger.
4. Clean all parts with alcohol and remove any foreign matter.
5. To reassemble, reverse steps 1 through 3 above.
9.6 CLEANING THE
FLOW SWITCH
63
SERVICE MANUAL
Medi-Therm II
REPAIR PROCEDURES
www.gaymar.com P/N 10187-000 7/98
For base replacement parts information, refer to figure 15, table 7, pp. 74-75. For
head replacement parts information, refer to figure 16, table 8, p. 76.
Repairs should only be performed by qualified personnel familiar with repair
practices for servicing medical devices.
Failure to install compressor shipping brace before shipment
can result in extensive damage to the refrigeration section.
(See p. 86, figure B.)
See figure 25, p. 86 for complete repackaging instructions to ship the Medi-Therm
II machine back to Gaymar or to a qualified Service Center. If you do not have
the original packing materials, please contact Gaymar's Technical Service
Department and a complete Customer Return Kit will be sent to you.
Be sure to obtain return authorization from our Technical Service Department
before shipping the machine.
9.7 REPLACEMENT
PARTS
CAUTION
9.8 SHIPPING /
REPACKAGING
INSTRUCTIONS
64
SERVICE MANUAL
Medi-Therm II
REFERENCE TABLES
www.gaymar.com P/N 10187-000 7/98
Table 4—Celsius-Fahrenheit Conversion
°C °F °C °F °C °F °C °F
0.0 32.0 11.5 52.7 23.0 73.4 34.5 94.1
0.5 32.9 12.0 53.6 23.5 74.3 35.0 95.0
1.0 33.8 12.5 54.5 24.0 75.2 35.5 95.9
1.5 34.7 13.0 55.4 24.5 76.1 36.0 96.8
2.0 35.6 13.5 56.3 25.0 77.0 36.5 97.7
2.5 36.5 14.0 57.2 25.5 77.9 37.0 98.6
3.0 37.4 14.5 58.1 26.0 78.8 37.5 99.5
3.5 38.3 15.0 59.0 26.5 79.7 38.0 100.4
4.0 39.2 15.5 59.9 27.0 80.6 38.5 101.3
4.5 40.1 16.0 60.8 27.5 81.5 39.0 102.2
5.0 41.0 16.5 61.7 28.0 82.4 39.5 103.1
5.5 41.9 17.0 62.6 28.5 83.3 40.0 104.0
6.0 42.8 17.5 63.5 29.0 84.2 40.5 104.9
6.5 43.7 18.0 64.4 29.5 85.1 41.0 105.8
7.0 44.6 18.5 65.3 30.0 86.0 41.5 106.7
7.5 45.5 19.0 66.2 30.5 86.9 42.0 107.6
8.0 46.4 19.5 67.1 31.0 87.8 42.5 108.5
8.5 47.3 20.0 68.0 31.5 88.7 43.0 109.4
9.0 48.2 20.5 68.9 32.0 89.6 43.5 110.3
9.5 49.1 21.0 69.8 32.5 90.5 44.0 111.2
10.0 50.0 21.5 70.7 33.0 91.4 44.5 112.1
10.5 50.9 22.0 71.6 33.5 92.3 45.0 113.0
11.0 51.8 22.5 72.5 34.0 93.2
10.0 REFERENCE TABLES
10.1 CELSIUS-FAHRENHEIT
CONVERSION
65
SERVICE MANUAL
Medi-Therm II
REFERENCE TABLES
www.gaymar.com P/N 10187-000 7/98
10.2 TEMPERATURE vs. RESISTANCE
Table 5—Temperature vs. Resistance
PATIENT PROBE, BLANKET WATER PROBE (RT2),
AND RESERVOIR PROBE (RT1) TEMPERATURE RESISTANCE
TEMPERATURE RESISTANCE TEMPERATURE RESISTANCE
°C °F (OHMS) °C °F (OHMS)
0 32.0 7355 26 78.8 2156
1 33.8 6989 27 80.6 2064
2 35.6 6644 28 82.4 1977
3 37.4 6319 29 84.2 1894
4 39.2 6011 30 86.0 1815
5 41.0 5719 31 87.8 1739
6 42.8 5444 32 89.6 1667
7 44.6 5183 33 91.4 1599
8 46.4 4937 34 93.2 1533
9 48.2 4703 35 95.0 1471
10 50.0 4482 36 96.8 1412
11 51.8 4273 37 98.6 1355
12 53.6 4074 38 100.4 1301
13 55.4 3886 39 102.2 1249
14 57.2 3708 40 104.0 1200
15 59.0 3539 41 105.8 1152
16 60.8 3378 42 107.6 1107
17 62.6 3226 43 109.4 1064
18 64.4 3081 44 111.2 1023
19 66.2 2944 45 113.0 983.8
20 68.0 2814 46 114.8 946.2
21 69.8 2690 47 116.6 910.2
22 71.6 2572 48 118.4 875.8
23 73.4 2460 49 120.2 842.8
24 75.2 2354 50 122.0 811.3
25 77.0 2252
66
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
P3 at J4
GROUND
HARNESS
P4 at J4
P5 at J3
PATIENT PROBE
ASSEMBLY
P2 at J2
P1 at J1
P6 at J2
POWER
SUPPLY
BOARD
GROUND
HARNESS
CHASSIS
GROUND
P7 at J1
CABLE
ASSEMBLY
26 CONDUCTOR
CONTROL DISPLAY
BOARD
SERVICE INFORMATION
Figure 8—Circuit Boards and Connectors (Head)
11.0 SERVICE INFORMATION
67
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
23
2
4
25
26
27
28
29
°
C
°
F
°
C/°F
STATUS:
ALERT MODE
TEMPERATURE
Blanket Patient
Set Point
SELECT
CHECK WATER FLOW
ADD WATER
REMOVE FROM USE NOW
MACHINE SHUT DOWN
CHECK PATIENT PROBE
Flow-OK Heat
In-Temp
Cool
TO CONTROL BLANKET TEMPERATURE:
TO CONTROL PATIENT TEMPERATURE:
TO MONITOR PATIENT TEMPERATURE:
(NO THERAPY)
CONNECT BLANKET(S)
PRESS MANUAL BUTTON
SET DESIRED BLANKET TEMP.
CONNECT BLANKET(S)
INSERT PATIENT PROBE
PRESS AUTO BUTTON
SET DESIRED PATIENT TEMP.
INSERT PATIENT PROBE
PRESS MONITOR BUTTON
MANUAL
MONITOR
SILENCE
ALARM
TEST
LIGHTS
AUTO
1
23
4
1
3
14 1
5
16 17
18
19
20
21
22
5
6
7
8
9
10
11
12
SERVICE INFORMATION
Figure 9—Operator Controls/Indicators
68
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
SERVICE INFORMATION
Item Name Function
1 FLOW-OK Indicates blanket water is flowing adequately.
2 HEAT Indicates blanket water is being heated. Refer to section 4.2 THERMAL SPECIFICATIONS, p..5
3 IN-TEMP Indicates the Medi-Therm II is controlling temperature at the desired setting.
4 COOL Indicates blanket water is being cooled. Minimum blanket temperature is 4°C (39.2°F).
5 ALERT Indicates an alert condition exists.
6 SELECT Indicates a mode must be selected. Flashes if set point buttons are pressed before selecting mode.
7 CHECK WATER FLOW Indicates the flow of water to the blanket has been restricted.
8 CHECK PATIENT
PROBE
Indicates the patient probe is sensing an abnormal patient temperature (below 32°C [89.6°F] or above
45°C [113°F]). An audible alarm accompanies this alert.
WARNING: It may indicate the patient probe has become dislodged, an incorrect probe is being
used, or a probe has become defective.
9 ADD WATER Indicates the water reservoir is below the recommended level.
10 REMOVE FROM USE
NOW / MACHINE
SHUT DOWN
Indicates the Medi-Therm II has shut down due to blanket water temperature exceeding either the high
or the low limit. It may also indicate the microprocessor has shut down the machine.
Remove the Medi-Therm II machine from use immediately.
11 TEST LIGHTS Enables the operator to confirm that all indicator lights and digital displays are working, and that the
audible alarm is functioning. The displays flash and the audible alarm sounds as long as the TEST
LIGHTS button is pressed.
12 SILENCE ALARM Temporarily silences the audible alarm The alarm will reactivate in approximately 5 minutes if the
condition persists. The SILENCE ALARM button will not function if the REMOVE FROM USE NOW /
MACHINE SHUT DOWN indicator is lit.
13 MANUAL Selects the manual mode of operation. In MANUAL mode, the operator must observe patient
temperature and adjust the blanket water set point temperature to obtain the desired results.
14 AUTO Selects the automatic mode of operation. In AUTO mode, the operator sets the desired temperature
and the patient temperature is automatically regulated to the operator-specified set point.
15 MONITOR Selects the monitor mode of operation. In MONITOR mode, the operator may monitor patient
temperature without providing therapy.
16 BLANKET Indicates the actual temperature of the water being delivered to the blanket. This display is illuminated
when MODE is set to either MANUAL or AUTO.
17 PATIENT Indicates actual patient temperature as sensed by the probe connected to the patient probe jack. This
display is illuminated when MODE is set to MANUAL, AUTO, or MONITOR and a patient probe is
plugged into the PATIENT PROBE jack.
18 * °C/°F INDICATOR Displays the temperature and setpoint in either degrees Celsius (°C) or Fahrenheit (°F).
Pressing the °C/°F button will display the appropriate scale and light the corresponding indicator.
19 * °C/°F BUTTON
20 LEADER LIGHTS Emphasizes whether blanket temperature or patient temperature is being set.
21
22
SET POINT
SET POINT BUTTONS
Indicates the desired SET POINT temperature. When operating in MANUAL mode, pressing the SET
POINT button (up or down) sets the desired BLANKET water temperature. When in AUTO mode,
pressing the SET POINT button sets the desired patient temperature.
23 OPERATING
INSTRUCTIONS
Condensed operating instructions are mounted on the machine head and on top of the water fill
opening cover.
24 WATER FILL
OPENING
Used to fill water reservoir to proper level. To fill, lift cover on the water fill opening and fill with distilled
water until the green band on the float stem is fully visible.
CAUTION: Add distilled water only. Failure to use distilled water may result in poor machine
performance. Do not use alcohol. Do not operate without water. Do not overfill.
25 PATIENT PROBE
JACK
Accepts patient probe plug connecting patient probe to machine.
Use only YSI 400 series probe or equivalent.
26 BLANKET
CONNECTIONS
Connects machine to quick-disconnects on the connector hose.
Quick-disconnect fittings are marked BLANKET 1 and BLANKET 2.
27 PROBE CHECK WELL Used to perform probe check (refer to Operating Manual for procedure).
WARNING: When performing the probe check, use a protective sheath (Becton-Dickinson
catalog 3700 oral sheath or equivalent) on probe to prevent cross-contamination.
28 ON / OFF SWITCH (Circuit breaker) Controls power to the unit.
29 AIR VENTS Permits adequate air circulation. Keep louvered openings clear on all three sides of the cabinet.
* Some models do not have the °C/°F feature
Table 6—Operator Controls/Indicators
69
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
1
1
Figure 11—Cooling flow diagram
When the Medi-Therm II machine is cooling, water flows in the path shown below.
Figure 10—Heating flow diagram
When the Medi-Therm II machine is heating, water flows in the path shown below.
1
SERVICE INFORMATION
70
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
LOW PRESSURE GAS
LOW SIDE
(SUCTION)
SERVICE
VALVE
CONDENSER
CONDENSER
FAN
HIGH PRESSURE LIQUID
HERMETIC
COMPRESSOR
HI
G
H PRE
SSU
RE
G
A
S
COLD TANK
PROBE ASSEMBLY
(RT1)
EVAPORATOR COIL
LOW PRESSURE
LIQUID
CAPILLARY
TUBE
FILTER
DRIER
HIGH SIDE
SERVICE VALVE
AIR
FLOW
SERVICE INFORMATION
71
Figure 12—Refrigeration flow diagram
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
SERVICE INFORMATION
®
Figure 13—Test setup
72
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
®
Figure 14—Machine disassembly
SERVICE INFORMATION
73
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
17
19
18
111389
6
5
4
2
1
16
15
10
21
7
3
14
12
SERVICE INFORMATION
Figure 15—Parts Diagram (Base)
74
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
ITEM DESCRIPTION
PART NUMBER
MTA5942 MTA5900 MTA5901
1
COMPRESSOR
07948-000 07948-000 07948-000
A. CAPACITOR, START - FOR UNITS WITH RING TERMINALS
N/A 90701-138 90701-138
CAPACITOR, START - FOR UNITS WITH PUSH ON TERMINALS
90701-140 90701-140 90701-140
B. RELAY - FOR UNITS WITH RING TERMINALS
N/A 77237-000 77237-000
RELAY - FOR UNITS WITH PUSH ON TERMINALS
77237-001 77237-001 77237-001
C. THERMAL OVERLOAD
RINGTERMINAL...R-134a UNITS
N/A 77851-000 77851-000
PUSHONTERMINAL...R-134a UNITS
77851-001 77851-001 77851-001
PUSHONTERMINAL...R-12UNITS
N/A 77238-000 77238-000
2
THERMOSTAT, WHITE DOT (S2 & S3)
77749-000 77749-000 77749-000
3
COMPRESSOR RELAY
91234-000 91234-000 91234-000
4 TEMPERATURE PROBE ASSEMBLY (RT2) KIT 77737-000 77737-000 77737-000
5
THERMOSTAT, BLACK DOT (S1)
77372-000 77372-000 77372-000
6
CIRCUIT BREAKER (CB1)
77754-000 77754-000 77754-000
CIRCUIT BREAKER COVER
77756-000 77756-000 77756-000
7
SOLENOID VALVE (SV1 & SV2)
77824-000 77824-000 77824-000
8
WATER LEVEL SENSOR
77757-000 77757-000 77757-000
9
TRANSFORMER ASSEMBLY (T1)
77826-000 77826-000 77826-001
10
QUICK DISCONNECT (FEMALE)
01080-000 01080-000 01080-000
11
FLOW SWITCH ASSEMBLY
77797-000 77797-000 77797-000
12
PUMP
07368-001 07368-001 07368-001
13
COLD TANK PROBE ASSEMBLY (RT1)
77759-000 77759-000 77759-000
14 FILTER DRIER ASSEMBLY
...R-134a UNITS
07954-000 07954-000 07954-000
...R-12UNITS
N/A 77414-000 77414-000
15
CASTER, R.H.
77101-001 77101-001 77101-001
16
CASTER, L.H.
77101-000 77101-000 77101-000
17
POWERCORDSTRAP
03791-000 03791-000 03791-000
REAR BAFFLE ASSEMBLY
07464-001 07464-001 07464-001
18
STRAIN RELIEF
90634-001 90634-001 90634-001
19
POWER CORD
77879-000 77879-000 77879-000
20
WRAPAROUND (Not Shown)
10288-000 10288-000 10288-000
21
HEATER ASSEMBLY
07370-000 07370-000 07772-000
22
RC NETWORK (Not Shown); connected between terminals 7 and 9 of COMPRESSOR RELAY
(ITEM 3).
77787-000 77787-000 77787-000
SERVICE
INFORMATION
Table 7—Parts List (Base)
75
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
°
C
°
F
°
C/°F
STATUS:
ALERT MODE TEMPERATURE
Blanket Patient
Set Point
SELECT
CHECK WATER FLOW
ADD WATER
REMOVE FROM USE NOW
MACHINE SHUT DOWN
CHECK PATIENT PROBE
Flow-OK Heat In-Temp Cool
TO CONTROL BLANKET TEMPERATURE:
TO CONTROL PATIENT TEMPERATURE:
TO MONITOR PATIENT TEMPERATURE:
(NO THERAPY)
CONNECT BLANKET(S)
PRESS MANUAL BUTTON
SET DESIRED BLANKET TEMP.
CONNECT BLANKET(S)
INSERT PATIENT PROBE
PRESS AUTO BUTTON
SET DESIRED PATIENT TEMP.
INSERT PATIENT PROBE
PRESS MONITOR BUTTON
MANUAL
MONITORSILENCE
ALARM
TEST
LIGHTS
AUTO
23
34
28
27
29
32
31
24
26
25
33
30
ITEM DESCRIPTION
PART NUMBER
MTA5942 MTA5900 MTA5901
23
COVER, WITH LABELS, CONTROL PANEL, FLOAT ASSY
77764-000 77764-000 77800-000
24
STEM
77760-000
(ALL PARTS)
77760-000
(ALL PARTS)
77760-000
(ALL PARTS)
25 FOAM FLOAT
26
RETAINING RING
27
PRECAUTIONS AND ALERTS LABEL
09853-000 09853-000 07781-000
28
INSTRUCTIONS LABEL
09852-000 09852-000 07780-000
29
PANEL, DIGITAL CONTROL ASSEMBLY
77884-000 77884-000 07782-000
30
PATIENT PROBE JACK ASSEMBLY
07311-000 07311-000 07311-000
31
CONTROL/DISPLAY PCB ASSEMBLY
07757-001 07757-000 07788-000
32
POWER SUPPLY PCB ASSEMBLY
07433-000 07433-000 07433-000
33
CABLE ASSEMBLY 26 CONDUCTOR
07481-000 07481-000 07481-000
34
COVER DOOR WITH LABELS, HINGES
77761-000 77761-000 77801-000
SERVICE INFORMATION
Figure 16—Parts Diagram (Head)
Table 8—Parts List (Head)
76
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
1
2
3
4
5
6
7
8
9
10
11
TB1
S1
S3
S2
IN
A
A
SECTION A-A
TERMINAL BLOCK TB1
A
BC
NOTE:
Positions 8 and 9 of TB1
are connected together.
SERVICE
INFORMATION
77
Figure 17—Original Thermostat Wiring Diagram for MTA5900/MTA5901
Figure 17A—New Thermostat Wiring Diagram for MTA5942 & MTA5900/MTA5901
1
2
3
4
5
6
7
8
9
10
11
TB1
S1
S3
S2
IN
A
A
SECTION A-A
TERMINAL BLOCK TB1
A
BC
NOTE:
Positions 8 and 9 of TB1
are connected together.
SERVICE MANUAL
Medi-Therm II
www.gaymar.com P/N 10187-000 7/98
[This page has been intentionally left blank.]
78
MEDI-THERM
TM
II IS
MADE IN THE USA
www.gaymar.com
