R-Pro › Field cases › VRF systems
EEV Stuck — Reduced Cooling/Heating Capacity
Likely causes
EEV coil open circuit or resistance failure — opening degree uncontrollable
Check: Remove EEV coil and measure resistance: normal 40–80Ω — check for open circuit (infinity) or short (0Ω)
What to do: Replace faulty coil → send EEV manual open command and verify valve movement → confirm refrigerant pressure normalization
Foreign object lodged in EEV body — mechanical valve seizure
Check: Recover refrigerant, disassemble EEV — visually inspect valve seat for debris, rust, sludge
What to do: Remove debris and clean → replace EEV assembly if severe → nitrogen pressure test for leaks after replacement
Moisture ingress in refrigerant — EEV internal icing causing seizure
Check: After refrigerant recovery, use acid/moisture test kit — moisture above 100ppm indicates contamination → check dryer filter saturation
What to do: Replace dryer filter → vacuum dry for ≥72 hours → charge with fresh refrigerant → verify EEV normal operation
If EEV coil resistance deviates from 40–80Ω, replace coil immediately — suspect coil before control board.
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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