TM9-4120-370-14
TO35E9-229-1
4-39. TEMPERATURE CONTROL THERMOSTAT (S1) - Continued,
a. Access
(1) Using allen wrench, loosen Temperature control thermostat knob setscrew,
(2) Remove knob.
(3) Using screwdriver and wrench, remove four screws and nuts that secure rear panel.
(4) Pull rear panel away from box as far as harness will allow,
b. Inspection
(1) Check that leads are properly connected. (See wiring diagram, Figure 4-20,)
(2) Check that capillary line and sensing bulb are not damaged,
(3) Check Temperature control thermostat for signs of overheating or other obvious damage. Replace if
damaged.
Test
c.
(1) Using Multimeter, place probes on the red and blue terminals.
(2) Turn Temperature control thermostat shaft fully clockwise.
(3) Check continuity. If temperature at sensing bulb is above 40F (5C), there should be no continuity.
(4) Slowly turn shaft counterclockwise until continuity is indicated. Turn shaft back and forth slightly to check
that switch contacts open and close on a very narrow band.
(5) Place Multimeter probes on the red and yellow terminals.
(6) Turn Temperature control thermostat shaft fully counterclockwise.
(7) Check continuity, If temperature at sensing bulb is below 90F (32C) there should be no continuity.
(8) Slowly turn shaft clockwise until continuity is indicated. Turn shaft back and forth slightly to check that
switch contacts open and close on a very narrow band.
(9) Replace Temperature control thermostat if it fails any of the above tests.
Removal
d.
(1) Tag and disconnect leads
(2) Using screwdriver and wrench, remove four screws and nuts.
(3) Remove Temperature control thermostat.
Installation
e.
(1) Using screwdriver and wrench, secure Temperature control thermostat to rear panel with four screws and
nuts.
(2) Place capillary line through notch and split grommet in rear panel,
(3) See tags and wiring diagram, Figure 4-20, and connect leads.
NOTE
Take care that sensing bulb capillary line is not kinked or mashed.
(4) Insert rear panel into box and aline holes,
(5) Using screwdriver and wrench, secure rear panel with four screws and nuts.
(6) Place Temperature control thermostat knob on shaft and aline setscrew with flat on shaft,
(7) Using allen wrench, tighten setscrew.
Follow-on procedure: Install control panel. (See para 437.)
4-80
