FRONT OF HOUSING - TM-5-4120-374-130081

TM 5-4120-374-13

ACTION

REMARKS

LOCATION/lTEM

FRONT OF HOUSING

a. Remove eight (8) screws securing return air grill to front panel.

2. Return Air Grill

b. Partially remove return air grill from front panel.

Carefully unwrap thermostat switch sensing bulb from expansion valve sensing

line. Use care to prevent damage to sensing bulb.

a. Loosen setscrews and remove three (3) knobs.

3. Thermostat Switch

b. Remove two (2) screws securing control panel plate to front

panel.

c. Remove control panel plate.

d. Tag and disconnect electrical leads from thermostat switch.

e. Remove two (2) screws securing thermostat switch to front

panel.

f. Unwrap thermostat switch sensing bulb and remove

thermostat switch.

4. Thermostat Switch a. Tag and disconnect electrical leads from thermostat switch.

b. With the thermostat switch set below room temperature,

use an ohmmeter and measure for continuity across the

thermostat switch terminals (see Wiring Diagram, Appendix F).

c. Verify that the resistance indicated is zero ohms.

d. Move thermostat switch setting to a position above room

temperature.

e. Verify that the resistance is infinity.

f. Replace thermostat switch if testing indicates that it is

defective.

5. Thermostat Switch a. Connect electrical leads to thermostat switch and remove tags.

b. Align holes in thermostat switch with holes in front panel.

c. Secure thermostat switch with two (2) screws.

d . Carefully wrap thermostat switch sensing bulb around

expansion valve sensing line.

e . Align holes in control panel plate with holes in front paneI.

f . Secure control panel plate with two (2) screws.

g. Install three (3) knobs and tighten setscrews.

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