LOW SUCTION AND DISCHARGE PRESSURE - TM-5-4120-352-140083

TM 5-4120-352-14

Table 5-1. Troubleshooting (cont`d)

Malfunction

Test or Inspection

Corrective Action

7. LOW SUCTION AND DISCHARGE PRESSURE

Check for low refrigerant charge by inspecting sight glass for bubbles or milky appearances. Also check system

Step 1.

for leaks.

Repair leaks and add refrigerant as necessary.

Step 2.

Check for indications of defective thermal expansion valve

Replace valve (para 5-28).

Check for indications of defective quench valve

Step 3.

Replace valve (para 5-29).

8. HIGH SUCTION PRESSURE

Step 1.

Check for indications of defective thermal expansion valve.

Replace valve (para 5-28).

Step 2.

Check for indications of defective quench valve.

Replace valve (para 5-29).

9. HIGH HEAD PRESSURE

Step 1.

Check to see if condenser coil is dirty.

Clean coil.

Step 2.

Check condenser coil temperature gradient for indications of refrigerant overcharge.

Discharge refrigerant (fig. 6-1) while observing head pressure and sight glass.

Step 3.

Inspect or teat condenser fan motor for defective operation.

Repair motor (para 6-8).

Step 4.

Inspect condenser louvers and actuating mechanism for correct adjustment and proper operation.

Adjust and clean as necessary. Replace inoperative components (para 5-20).

Step 5.

Check for indications of defective quench valve.

Replace defective valve (para 5-29).

Check to see if the compressor is defective.

Step 6.

Replace defective compressor (para 5-17).

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