WarningRefrigeration
CO2 Parallel (Flash Gas) Compressor Fault
The parallel compressor pulls flash gas directly from the receiver in warm ambient to boost efficiency. When it won't run or stage, flash gas dumps through the FGB valve to MT suction and efficiency (and MT capacity) suffer.
Symptoms
- Parallel compressor not staging on in high ambient / transcritical operation
- High flash-gas bypass valve opening; MT compressors loaded heavily
- Higher-than-expected energy use, MT suction pressure creeping up
- Receiver pressure hard to hold on setpoint on hot days
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