TM 9-4120-399-14
Table 4-3. Unit Troubleshooting.
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Step 2.
Using wiring diagram Figure 1-4, check individual wires for tightness
and continuity.
Tighten, repair, or replace as indicated.
Step 3.
Check operation of fan motor relay (K8).
Test relay. Replace relay if defective per para. 4-39.
Step 4.
Check operation of mode selector switch.
Test switch. Replace defective switch per para. 4-43.
Step 5.
Check operation of fan motor.
Test motor. Replace per para. 4-32.
EXCESSIVELY NOISY OPERATION.
10.
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
c o m p r e s s o r which can seriously
damage o r destroy compressor.
Contact your supervisor.
Step 1.
Check fans for looseness or damage, and for rotational clearance.
Tighten loose fans, adjust rotational clearance, or replace fans per
para. 4-30 and 4-47.
Step 2.
Check all internal components for looseness, vibration, and security.
Tighten, adjust, and secure as necessary.
If unit is still noisy, notify supervisor.
4-33
