High Suction Pressure
refrigeration
Description
The refrigeration system runs with suction pressure greater than 98 psig (6.7 bar) for more than 10 minutes; engine and electric operation give alarm only, or shut down if configured.
Activation Conditions
The refrigeration system is running and the suction pressure has been greater than 98 psig (6.7 bar) for more than 10 minutes.
Unit Behavior
Engine Operation: Alarm only or (if configured for shutdown) engine and unit shutdown and alarm. Electric Operation: Alarm only or (if configured for shutdown) refrigeration system shutdown and alarm with PSCON still energized.
Reset Conditions
Auto reset when suction pressure is less than 75 psig (5.1 bar) for five minutes and configured for Alarm Only, or Auto Reset after 15 minutes if configured as a Shutdown Alarm or, alarm may be manually reset via keypad or by turning the unit off, then back on again.
Corrective Actions
1. Check Refrigerant Charge - Refer to Section 8.7.2. Charge must be correct. 2. Perform Pretrip Check - Clear the Active Alarm list, then run a Pretrip and check for any new alarms. Any active alarms must be corrected and cleared before proceeding. 3. Check System Pressures - Install manifold gauge set and check and compare compressor discharge and suction pressures with those shown in Unit Data. Suction pressure must be above 3 psig (0.2 bar) and should be in the normal range for ambient and refrigerated compartment conditions. Refer to Section 8.9.11. 4. Check Compressor a. Check compressor for excessive vibration or noise. Replace compressor b. Cover condenser and build-up discharge pressure. Must be able to raise pressure to 400 psig (27.2 bar). 5. Check Transducer Wiring. Refer to Section 8.9.11. a. Inspect transducer and connector pins and terminals. (See wiring schematic Section 10.3.) Verify there is no physical damage to sensor. Verify there is no damaged or corroded pins in plug. b. Check for voltage at the transducer plug between pins A (+) and B (ground). Voltage should be approximately 12VDC. If OK, go to next step. If not, continue with this step. c. Reconnect the transducer plug. Check for voltage between pin C and ground. Voltage should be greater than 0.24 VDC and less than 5 VDC. 6. Check Expansion Valve (EVXV) a. Visually inspect valve. Check coil is seated properly. b. Check valve. Refer to Section 8.9.8.