Table 4-1. Troubleshooting - continued

TM 5-4120-339-14

Table 4-1. Troubleshooting (continued)

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

AIR CONDITIONER NOISY DURING OPERATION (continued)

Adjust expansion valve if superheat is not correct (paragraph 4-15).

Step 4.

Inspect quench valve and check superheat (paragraph 4-16).

Repair or replace damaged or defective quench valve.

Adjust quench valve if

superheat is not correct (paragraph 4-16).

AIR CONDITIONER STOPS DUE TO HIGH PRESSURE SWITCH TRIPPING

Step 1.

Check air conditioner operating pressures for excessive refrigerant in system (table 4-3).

Release excess refrigerant from system until the proper charge is attained

Step 2.

Check for restriction in condenser air flow.

Clean condenser coil and/or remove restriction.

AIR CONDITIONER OPERATES CONTINUOUSLY ON COOLING CYCLE.

Step 1.

Check for insufficient refrigerant in system (bubbles in sight glass).

Step 2.

If adding refrigerant to system does not clear up bubbles in sight glass, there may be air in

the system.

Open system and remove refrigerant (figure 4-2), purge system (paragraph 4-8),

evacuate system (figure 4-4), and recharge the system with refrigerant

SIGHT GLASS APPEARS YELLOW INSTEAD OF GREEN

Step 1.

Yellow appearance of sight glass is caused by contamination in the refrigerant.

Open system and remove refrigerant (figure 4-2), remove dehydrator (figure 4-16),

purge and dry system (paragraph 4-8), install new dehydrator (figure 4-16), evacuate

system (figure 4-4) and recharge system with refrigerant (paragraph 4-10).

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