Applicable Systems
Carrier Transicold Refrigeration Unit
Symptoms
The Carrier Transicold unit displays alarm CR002, indicating high discharge pressure. The condensing pressure has exceeded the safety limit, causing the unit to trip the high-pressure safety switch.
Possible Causes
- Condenser fan motor has failed or is running at reduced speed, reducing condenser capacity
- Refrigerant has been overcharged, flooding the condenser and raising head pressure
- Non-condensable gases such as air have entered the system and are trapped in the condenser
Troubleshooting Steps
- Step 1: Check the condenser fan operation and the fan speed control output from the controller
Fan motor is running at full speed and the condenser air discharge temperature is 5-10C above ambient - Step 2: Verify the refrigerant charge by checking subcooling at the condenser outlet
Subcooling is within 3-5C of the design value, confirming a correct charge - Step 3: Perform a non-condensables purge test by comparing condenser pressure to the corresponding saturation temperature
Saturation pressure matches the actual condenser pressure, confirming no non-condensable gases are present
How to Reset
To reset: 1) Repair or replace the condenser fan. 2) Correct the refrigerant charge. 3) Purge non-condensable gases. 4) Reset the high-pressure switch and restart the unit.
Source: Carrier Transicold Refrigeration Unit Manual, Carrier Corporation
Category: Refrigeration