LPCO

TM 10-4110-262-13&P

0029 00

LPCO

The low pressure cutout switch is located on the suction line in the condenser section behind the receiver tank. If the

suction pressure drops between 5 to 11 inHg of vacuum (-17 to -37 kPa), it opens the contactor to stop the

compressor. To check the low pressure cutout:

1. Install a manifold gauge assembly.

2. Close the receiver tank outlet valve and run the unit in cool.

3. When the suction pressure drops between 5 to 11 in. Hg of vacuum (-17 to -37 kPa), the LPCO will open and the

compressor will stop.

4. If not, replace the LPCO.

Dehydrator

Indications that the dehydrator may need to be replaced are:

1. Moisture indicated in the sight glass The sight glass indicates on the presence of moisture. If

moisture is present, replace the dehydrator.

2. Condensation or frost on the refrigeration lines downstream from the dehydrator Frost,

condensation, or a temperature differential across the dehydrator indicates a restriction.

3. When the system has been open for an extended period of time during service.

4. During system cleanup.

Receiver

Indications that the receiver needs to be replaced are:

1. Condensation or frost on the refrigeration lines downstream from the receiver A partially plugged

(obstructed) receiver will act as an expansion device and cause an accumulation of frost or

condensation downstream from the obstruction.

2. The compressor pumps down the low side to vacuum If the refrigeration system gauges indicate

that the low side is in vacuum, confirm that the receiver tank outlet valve is backseated. Install a high

pressure manifold gauge assembly on the receiver tank outlet valve, gauge the receiver tank outlet

valve, and confirm that the receiver tank is being pressurized. If it is not being pressurized, the

obstruction may be in the receiver. Recover the refrigerant and remove the receiver as outlined in WP

0039 00. Blow nitrogen through the receiver to confirm that the obstruction is in that component. If the

obstruction is confirmed, replace the receiver.

0029 00-5