ARMY TM 9-4120-380-14
NAVY EE-000-BA-MMA-010/7053-AC
AIR FORCE TO 35E9-136-21
Table 4-2. Unit Maintenance Troubleshooting - Continued
Malfunction
Test or Inspection
Corrective Action
7. CONDENSER FAN MOTOR (B3) DOES NOT OPERATE - Continued
Step 2. Check operation of fan motor contactor (K3).
Test contactor (paragraph 4.34). Replace contactor if defective.
Step 3. Check operation of fan motor (B3).
Inspect and test motor (paragraph 4.51). Replace motor if defective.
Step 4. Check operation of MODE SELECT switch (S1).
Inspect switch (paragraph 4.28). Replace switch if defective
Test relay (paragraph 4.41). Replace relay if defective.
8. EXCESSIVE NOISE WHEN COMPRESSOR STARTS
If a knocking or hammering sound is heard when compressor starts, turn MODE
SELECT switch to OFF immediately. Such noise is usually caused by liquid
refrigerant in compressor, which can seriously damage or destroy compressor.
Step 1. Turn compressor OFF, wait a minute and turn to AUTO.
If compressor continues to knock, turn compressor OFF immediately and contact Direct Support
Maintenance.
9. EXCESSIVE NOISE OPERATION
Step 1. Isolate source of noise as near as possible, both by ear and touch Listen and feel at both the front and
back of the cabinet.
Step 2. Check fans for looseness or damage and for rotational clearance.
Tighten loose fans (paragraphs 4.47 and 4.50).
Step 3. Check all internal components for looseness, vibration and security.
Tighten, adjust and secure as necessary.
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