DIRECT SUPPORT TROUBLESHOOTING PROCEDURES - continued

TM 9-4120-430-14

0042 00

FAULT PROCEDURE 9.

SUCTION PRESSURE TOO LOW - Continued

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

SUCTION PRESSURE TOO LOW

Replace faulty expansion valve. (Refer to WP 0057 00.)

Step 2.

Feel filter-drier for temperature difference. Discharge end will feel cooler than input end if clogged,

or discharge end may be frosty or sweaty (for low suction pressure).

Replace filter-drier. (Refer to WP 0051 00.)

FAULT PROCEDURE 10.

SUCTION PRESSURE TOO HIGH

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

SUCTION PRESSURE TOO HIGH

Step 1.

Check suction line and accumulator for excessive sweating and flood back of liquid to compressor.

Expansion valve is truck open. Replace expansion valve. See WP 0062 00.

Step 2.

Check for defective linear actuator, broken or loose louver actuator linkage.

Repair or replace defective linear actuator. (Refer to WP 0060 00.) Repair or replace louver

actuator linkage. (Refer to WP 0021 00 and WP 0060 00.)

Step 3.

Test for defective expansion valve.

Test for properly functioning expansion valve per WP 0057 00. Replace defective expansion

valve. (Refer to WP 0057 00.)

FAULT PROCEDURE 11.

LOW HEAT OR NO HEAT

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

LOW HEAT OR NO HEAT

Step 1.

Check operation of evaporator fan and motor. (Refer to WP 0035 00.)

Repair or replace faulty fan or motor. (Refer to WP 0035 00.)

Step 2.

Disconnect and remove heater elements, and apply 115-volt AC power to check for open circuit in

element or check resistance. Element should heat.

Replace faulty heating elements. (Refer to WP 0036 00.)

END OF WORK PACKAGE

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