Suction Pressure Regulator

TM 10-4110-262-13&P

0029 00

Suction Pressure Regulator

1. Install the manifold gauge assembly.

2. Run unit until the IC temperature is 36 F or lower.

3. Initiate manual defrost cycle.

4. Monitor suction pressures.

5. If suction pressure rises above 65 psig, adjust the suction pressure regulator until the suction pressure is

maintained at 65 psig.

6. Remove the manifold gauge assembly.

7. Perform system operation check in WP 0010 00.

HPCO

The HPCO is located on the discharge line near the compressor. If the discharge pressure rises

above 45010 psi (3103 kPa), the switch opens, de-energizing the power relay coil and removing power to the RU.

To test contractors:

1. To determine if the HPCO contacts are closed, disconnect each HPCO connector. Check for

continuity through the HPCO switch.

2. To determine if the HPCO is functioning properly, do the following:

Connect a manifold gauge assembly to suction and discharge service valves.

Set the thermostat well below the IC temperature so that the unit will be in cool.

Raise the discharge pressure of the compressor by first blocking the condenser coil airflow. When the discharge

pressure reaches 450 psi (3,103 kPa), the high pressure cut-out will switch off the unit.

NOTE

Unit will restart over the discharge pressure drops below 450 psi 10 psi.

3. If HPCO does not function as rated, replace HPCO.

0029 00-4