d. Fit the fabric cover over the backoftbe air conditioner, and secure all four sides with 18 screws and washers.
Section XIX. HEATER THERMOSTAT
The heates thermostat is a thermal overload protector, located behind and between the heating elements. It is electrically
connected to the heating elements in such a way that if temperature exceeds a preset maximum, the heater thermostat
opens to the circuits. When the temperature has returned to normal. the thermostat automatically resets, thereby closing the
circuits to the heating elements.
Obtain access to the heater thermostat as directed below:
a. Remove 18 screws and washers from the four sides of the fabric cover. and remove the cover.
b. Remove 15 screws and packing washers from the top surface of the top panel, and five screws from the rear
flange. Remove the top panel.
Remove the heater thermostat from the air conditioner as follows:
Disconnect power from the air conditioner before performing maintenance on the electrical system.
The voltage used can be lethal.
If desired, two heating elements maybe removed for greater convenience in manipulating the thermostats
a. Tag and disconnect wire leads from the heating elements to the heater thermostat.
b. Remove two screws and self-locking nuts from the heater thermostat. Remove the thermostat.
a. Visually inspect the heater thermostat for cracks in the housing, missing pieces or other damage. Replace if
damaged. Test as follows:
or other continuity tester, check continuity
of the wire
5-6 and 4-6 of the heater thermostat. Continuity should be indicated.
c. Tape the bulb of a thermometer or junction of a thermocouple to the body of the heater thermostat, and leave
the continuity tester connected to any two of the wire leads. Gradually apply heat. and observe both the thermometer and
the continuity tester. Continuity should drop out at 194 9F (90 5C). While still continuing to watch the
thermometer and the continuity test, let the heater thermostat cool. Continuity should be re-established at 142 17F
d. Repeat step b with the continuity tester connected to each of the other two pairs of terminals.
e. If the heater thermostat does not meet temperature and continuity requirements, replcae it.