High Discharge Pressure

1. If Alarm Occurs During Pretrip Test 12, 13 or 14 (Pretrip descriptions can be found in Section 3.6) Check that SV1 is opening. During Pretrip tests 12, 13 and 14, SV1 may be de-energized for one second to reduce discharge pressure (Refer to Figure 2.9). If SV1 fails to open during the one second that it is de-energized, this alarm may occur. Repair SV1 as required. 2. Check System Pressures: Install a manifold gauge set to check and compare actual compressor discharge and suction pressures with those shown in Unit Data. Refer to Section 8.9.10 for instruction on comparison. If discharge pressure is in normal range, proceed to step 6. 3. Check Airflow Through Radiator and Condenser Coil a. Inspect condenser and radiator. Ninety percent or more of the coil surface must be undamaged. Condenser/Radiator coil must be clean. b. Check airflow (with unit running). Verify that there is even airflow through the entire coil and no “dead” spots. c. Check upper and lower fan belt tension and condition. Verify that there is no glazing, cracking or slipping. Replace if required. Refer to Section 8.6. 4. Perform Pretrip (Section 3.6): Check for Pretrip alarms. Any active alarms must be corrected and cleared before proceeding. 5. Check Refrigerant Charge: Refer to Section 8.7.2. 6. Check HPS Power and Wiring a. Inspect switch, connector pins and terminals. Verify that there is no physical damage to the switch. Check the connections for damage and corrosion. b. Disconnect switch connector and check for power at the A position (includes DM7, J1A, J1B and SP- 31). If a minimum of 11 VDC is not present, check connectors and wiring between terminals for damage, moisture or corrosion (includes SROS, J1A, J1B and SP31). c. Check continuity from the switch connector B position to PM22. If good continuity is not present, check wiring for damage. 7. Check HPS Switch a. With discharge pressure below the switch closing pressure (refer to Section 2.10), disconnect switch connector and check continuity across the switch. Switch closed. b. Check/test switch operation. Refer to Section 8.9.9 8. Refer to Refrigeration Troubleshooting (Section 9.3): Discharge pressure must be in range for the current ambient and refrigerated compartment conditions.