Expansion Valve (Liquid Quench)

TM 5-4120-393-14

5-20. Expansion Valve (Liquid Quench)

This task covers:

a. Inspection

c. Removal

b. Test

d. Installation

Initial setup.

Tools:

Tool kit, service, refrigeration unit NSN 5180-00-596-1474

Personnel: 1

Equipment condition:

1. Turn unit power off at power source. If there is a chance that it will be turned on, also disconnect power

cable to air conditioner.

2. Remove lower front panel. See para 4-24.

3. Remove junction box number two. See para 4-46.

General Safety Instructions:

WARNING

Disconnect input power to the air conditioner before performing any internal

maintenance. Voltages used can KILL. Shutting the unit off at the control panel

does not disconnect unit power.

INSPECTION

Inspect for evidence of leaks, kinked, or otherwise damage capillary line, and loose or missing mounting hardware.

Check thermal bulb to see that it is securely clamped to the suction line.

If a leak is suspected or indicated, test per paragraph 5-12.

TEST

NOTE

The expansion valve as supplied with the unit is preset at the factory. This valve

should not be adjusted unnecessarily.

Perform a refrigerant check on unit in accordance with para 5-15. Leave gages or service manifold attached.

Unwrap insulation from compressor suction line so that sensing bulb and an adjacent section of the line is exposed.

Attach an accurate thermometer to an exposed surface of suction line adjacent to the sensing bulb; use a small

amount of thermal mastic, if available, to improve conductivity.

Check that service valve and gage connection to low (suction) sides are open. Note pressure indicated on gage and

temperature indicated on thermometer.

5-47