TM 9-4120-399-14
5-23. EXPANSION VALVE.
This Task Covers:
c. Installation
b. Removal
a. Testing
Initial Setup:
Tools Required
Tool kit, Refrigeration
Material's Rewired
Insulating tape (Appendix E, item 24)
Equipment Condition
Air conditioner shut down and cool.
Intake (return air) guard removed (See para. 3-5).
Discharge the refrigeration system (See para. 5-7).
a. Testing. The expansion valve as supplied with the unit is preset at the factory. This
valve cannot be adjusted.
(1) Perform a refrigerant pressure check on unit in accordance with para. 5-13. Leave
gages or service manifold attached.
(2) Remove the suction line insulation from the area of the sensing bulb (12). Observe
location and position of bulb for reinstallation.
(3) Remove two screws (9) and two nuts (10) from two clamps (11) on sensing bulb
(12).
WARNING
High voltages can kill or seriously injure personnel. Exercise extreme
caution since the following test must be conducted with the power on.
CAUTION
Damage to the capillary tube will cause the unit to malfunction. Use
care not to damage or kink the capillary.
(4) Place the sensing bulb (12) in a container of ice water or crushed ice so that it is
reduced to a temperature near 32 deg. F(0 deg. C).
(5) Set the temperature control thermostat knob to fully COOLER (counterclockwise),
place one hand on the exposed suction return line, and start the air conditioner in COOL mode.
If a drop in temperature is felt on the suction return line, the expansion valve is not closing fully
and should be replaced. If the return line temperature remains constant, check the pressure gage;
