Solenoid Valves (K3 and K4)

TM 5-4120-393-14

5-17. Solenoid Valves (K3 and K4)

This task covers:

a. Test

c. Installation

b. Replace

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.

NOTE

The following basic instructions apply to both the equalizing solenoid valve (K4)

and the liquid line solenoid valve (K3).

TEST

Check to be sure power has been disconnected.

Disconnect wiring harness connector P5 from connector J5 on solenoid valve K3 and /or wiring harness connector P6

from connector J6 on solenoid valve K4.

Use a multimeter set on lowest OHMS scale to check for continuity between contacts A and B in solenoid valve

connector. If continuity is not found, coil is open and must be replaced.

Use multimeter to check for continuity between each contact in solenoid valve connector and coil casing. If continuity

is found between either contact and case, the coil is grounded and should be replaced.

If continuity checks are satisfactory, apply 24 volts dc from an external power supply across contacts A and B in

solenoid valve connector, and listen for a sharp click when the valve changes position. If a click is not heard, internal

valve problems are indicated and entire valve should be replaced.

5-38