Table 4-9. Air Conditioner System Noises - Troubleshooting. - continued

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Table 4-9. Air Conditioner System Noises - Troubleshooting.

TM-55-1905-220-14-8 Landing Craft Utility LCU 1671-1679 NSN 1905-01-009-1056 Manual

Table 4-9. Air Conditioner System Noises - Troubleshooting. - continued

TM 55-1905-220-14-8

4-5. GENERAL (Continued).

Table 4-9. Air Conditioner System Noises Troubleshooting (Continued).

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

Step 5. Slugging due to floodback of refrigerant:

a. Improperly set thermal expansion valve.

b. Expansion valve remote bulb loose or incorrectly placed.

c. Suction lines not looped.

Eliminate liquid refrigerant return:

a. Adjust thermal expansion valve.

b. Check installation and location of thermal bulb. Correct if necessary.

c. Loop suction lines to prevent floodback on off cycle.

Step 6. Hydraulic knock due to excess oil in circulation.

Remove excess oil. Check for floodback.

Step 7. Noise level varies with unloading due to defective valve lifter mechanism.

Refer to capacity control troubles.

Step 8. Wear of parts such as piston pins, connecting rod bearings, etc.

Replace worn parts.

Step 9. Vibration of disc in discharge stop valve causes rattle or howl.

Backseat valve fully.

2. Pipe rattles.

Step 1. Improper support or isolation of piping.

Check piping. Support firmly with suitable hangers.

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