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Scroll Poppet Valve Fails to Close — Reverse Rotation Noise After Shutdown
Likely causes
Poppet valve spring fatigue or debris stuck → fails to close fully → high-pressure refrigerant backflows
Check: Listen for 'hissing' or 'humming' reverse rotation noise for 1~2 sec after stop. Check for short-cycling history (ON/OFF ≥ 6 times/hour). Visually inspect poppet valve seat for wear or carbon sludge
What to do: Clean poppet valve (remove debris + check spring tension) or replace. If prolonged backflow, check for secondary bearing and tip seal damage. Adjust control settings to reduce cycling frequency
Frequent ON/OFF cycling — more than 6 times per hour accelerates poppet valve deterioration
Check: Check control log for start/stop count. Narrow temperature differential (±0.5°C or less) causes frequent cycling
What to do: Widen temperature differential to at least ±1~2°C → set start interlock timer to 3~5 minutes (prevent short-cycle restart)
The 1~2 second reverse noise after shutdown sounds minor but repeatedly shortens bearing life significantly. Always log and compare weekly start counts.
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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