TM 9-4120-378-14
Table 5-1. Direct Support Troubleshooting - Continued
Malfunction
Test or Inspection
Corrective Action
5.
COMPRESSOR EXCESSIVELY NOISY
Step 1.
Listen for knocking.
Check for high pressure indicating that liquid refrigerant is returning to compressor.
(Refer to paragraph 5.10 and table 5-2.)
Check for high discharge pressure indicating overcharge of refrigerant. (Refer to
Step 2.
a. Purge or bleed off excess refrigerant.
b. Check HIGH pressure switch or pressure regulator valve.
6.
SUCTION PRESSURE TOO LOW OR TOO HIGH
Step 1.
Stop compressor and check expansion valve as follows:
a.
Remove remote bulb from well in suction line.
b.
Place bulb in ice water for 1-2 minutes.
c.
Start compressor.
d.
Remove bulb from ice water and hold it in one hand to warm it. At the same time,
check the suction line for rapid change of temperature, which indicates
flood-through of liquid refrigerant. If liquid floods through valve, it is operating
satisfactorily. If not, valve or remote bulb is faulty.
Do not let liquid flood back into compressor or compressor will be seriously
damaged.
e. Replace faulty expansion valve. (Refer to paragraph 5.17.)
Step 2.
Feel dehydrator for temperature difference. Discharge end will feel cooler than
input end if clogged, or discharged end may be frosty or sweaty.
Replace dehydrator. (Refer to paragraph 5.25.)
5-5
