CONDITIONED AIR (EVAPORATOR) FAN DOES NOT START, OR STOPS DURING OPERATION, IN ANY OPERATING MODE.

TM 5-4120-393-14

Table 4-2. Unit Maintenance Troubleshooting

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

6. CONDITIONED AIR (EVAPORATOR) FAN DOES NOT START, OR STOPS DURING OPERATION, IN ANY

OPERATING MODE.

Step 1.

Check operation of conditioned air (evaporator) fan motor relay (K8).

WARNING

Disconnect input power before performing internal electrical troubleshooting.

Voltages used can be deadly.

Test relay. (See para 4-43.) Replace relay if defective.

Step 2.

Check operation of conditioned air (evaporator) fan motors (B3A and B3B).

Test motors. (See para 4-56.) Contact Intermediate Direct Support Maintenance if motors

are defective.

Step 3.

Check operation of mode selector switch (S).

Test switch. (See para 4-38.) Replace switch if defective.

CAUTION

If a knocking or hammering sound is heard when compressor starts, turn mode

selector switch to OFF, immediately. Such noise is usually caused by liquid

refrigerant in compressor, which can seriously damage or destroy compressor.

Contact Intermediate Direct Support Maintenance.

7. EXCESSIVE NOISE WHEN COMPRESSOR STARTS.

WARNING

Disconnect input power before performing internal electrical troubleshooting.

Voltages used can be deadly.

Step 1.

Check for a defective compressor.

(Contact Intermediate Direct Support Maintenance.)

8. EXCESSIVELY NOISY OPERATION.

Step 1.

Isolate source of noise as near as possible, both by ear and touch.

Listen and feel at both front and back of cabinet.

4-40