R-Pro › Field cases › Refrigeration systems
Electronic expansion valve (EEV) not responding
Likely causes
EEV driver failure
Check: Measure EEV coil resistance (compare to model-specific rated value)
What to do: Measure EEV coil resistance (compare to model-specific rated value) → Measure driver output signal voltage → Check suction temperature sensor resistance → Test EEV operation in forced manual control mode → Replace coil if defective (many models support coil-only replacement)
EEV coil open circuit
Check: Measure driver output signal voltage
What to do: Measure driver output signal voltage → Check suction temperature sensor resistance → Test EEV operation in forced manual control mode → Replace coil if defective (many models support coil-only replacement)
Control board signal fault
Check: Check suction temperature sensor resistance
What to do: Check suction temperature sensor resistance → Test EEV operation in forced manual control mode → Replace coil if defective (many models support coil-only replacement)
Temperature sensor failure (superheat sensing error)
Check: Test EEV operation in forced manual control mode
What to do: Test EEV operation in forced manual control mode → Replace coil if defective (many models support coil-only replacement)
EEV stuck closed causes poor cooling; stuck open causes liquid slugging
All 565 cases work offline in R-Pro, with error codes for 62 brands and P-T data for 108 refrigerants.
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