EXPANSION VALVE REPLACEMENT

TM 5-4120-359-14

(8) Hold the front cover with radio frequency filter, harnesses, and cables in place in mounted position on the unit

to minimize air leaks.

(9) Operate the air conditioner in the cooling mode for about 30 minutes, briefly removing front panel and

observing the thermometer or thermocouple dial to see that the temperature has stabilized. When the temperature

remains unchanged for at least two minutes, record the temperature and pressure.

(10) Compare the recorded temperature and pressure with those in table 4-3. The temperature measured should

(11) If adjustment is necessary, remove the cap from the expansion valve (fig. 4-35) and turn the adjusting stem

counterclockwise to decrease the superheat and clockwise to increase the superheat. When adjusting the valve, make no

more than one turn of the stem at a time and observe the change in the superheat closely to prevent overshooting the

desired setting. Allow unit to stabilize before taking reading.

(12) When the proper setting is obtained, turn off air conditioner and replace the cap on the valve adjusting stem.

(13) Remove the thermometer or thermocouple probe from the suction line, and replace the insulating material.

Close the LOW SIDE service valve, remove the charging manifold and hose, and install the cap on the service valve gage

port.

e. Reassemble

(1) Turn power off.

(2) Disconnect remote control module assembly and power cable.

(3) Slip the sensing bulb into its mounting bulb straps. Be sure the bulb is on the top of the suction line in original

position and tighten the two nuts and screws. Be sure the sensing bulb is making good metal-to-metal contact with the

suction line.

(4) Cover the bulb and suction line with two layers of insulation tape, item 14, Appendix E. Apply in spiral with

overlapping edges.

(5) Carefully slip front evaporator cover with radio frequency filter and harnesses attached back in place.

(6) Aline holes and using screwdriver, secure the cover with eight screws.

Follow-on Procedure: Install air conditioner on shelter. (See paragraph 3-6.)

4-37. EXPANSION VALVE REPLACEMENT

For inspection, test, and adjustment, see paragraph 4-36.

Preliminary Procedures:

1. Remove air conditioner from shelter. (See paragraph 3-6.)

2. Discharge refrigerant. (See paragraph 4-5.)

3. Remove evaporator coil and piping. (See paragraph 4-34.)

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