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Scroll Internal Liquid Slug — Tip Fracture and Scroll Volute Crack

Likely causes

TXV/EEV superheat below 3°C — liquid refrigerant enters suction, strikes compression chamber directly

Check: Immediately after startup: metallic hammering noise + current spikes to 150~200% rated then immediate overload trip. Measure superheat — must be ≥5°C for normal operation

What to do: Tighten TXV screw to achieve 5~8°C superheat (for EEV, enter target SH in controller) → establish SOP: fans first, wait 3 min, then start compressor → disassemble compressor: inspect tip fractures — if damaged, replace entire scroll assembly

Metal debris from fractured tips contaminates entire refrigerant circuit

Check: Take oil sample: visually check for metal particles + magnet test. When replacing filter drier, check screen for contamination or blockage

What to do: Full system flush (recover all refrigerant → circulate flushing agent → recover again) → replace all filter driers → replace compressor → confirm vacuum ≤500μm before recharging

Field tip

Knocking at startup + immediate trip = liquid slug confirmed. Metal debris circulating through the system causes secondary damage to EEV, expansion valves, and solenoids. Oil sampling before restart is mandatory.

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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