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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
