Moisture in the System

After making the above checks operate the system and check the performance. If the Condition is not rectified.

1. Inspect the system for overcharge of refrigerant and rectify as follows.
   • A. Discharge the system, until a stream of bubbles appear in the sight glass and both gauge readings drop to below normal.
   • B. Add new refrigerant until the bubbles disappear and the pressures are normal. Then add 0.25 to 0.5 lb. of additional refrigerant.
2. Operate the system and check the performance. If the gauge readings are still too high.
3. Depressurise the system.
4. Remove and inspect the condenser for oil clogging. Clean and flush the condenser to ensure the free passage refrigerant or renew the condenser.
5. Renew the receiver-drier.
6. Evacuate the system using a vacuum pump Recharge the system with new refrigerant. Operate the system and check the performance

Moisture in the System

Complaint.

Cooling not adequate during the hot part of the day.

Note: Cooling may be satisfactory during early morning / late evening but inadequate during the hot part of the day.

Condition.

1. The low side gauge reading normal but may drop into vacuum during testing.
2. The high side gauge reading normal but drops when the low side drops into vacuum. The sight glass may show tiny bubbles.
3. The discharge air from the evaporator is cold but becomes warm when the low side gauge drops into vacuum.

Diagnosis.

Excessive moisture in the system.

Desiccant agent saturated with moisture which is released during high temperatures. The moisture collects and freezes in the expansion valve which stops the refrigerant flow.

Correction.

1. Depressurise the system.
2. Renew the drier bottle.
3. Evacuate the system using a vacuum pump.
4. Recharge the system with new refrigerant.
5. Operate the system and check the performance.