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Compressor Overheating from Excessive Suction Superheat

Likely causes

Refrigerant shortage causing suction gas overheat

Check: Check for refrigerant leak with leak detector

What to do: Check for refrigerant leak with leak detector → Measure TXV superheat: evap outlet temp − suction sat. temp (normal 5–10°C) → If superheat is high, turn TXV adjustment screw counterclockwise 1/4 turn at a time → Inspect suction line insulation for damage → Measure temperature difference across filter drier (>2°C = blockage suspected)

TXV set too restrictive (superheat set too high)

Check: Measure TXV superheat: evap outlet temp − suction sat. temp (normal 5–10°C)

What to do: Measure TXV superheat: evap outlet temp − suction sat. temp (normal 5–10°C) → If superheat is high, turn TXV adjustment screw counterclockwise 1/4 turn at a time → Inspect suction line insulation for damage → Measure temperature difference across filter drier (>2°C = blockage suspected)

Poor suction line insulation absorbing heat

Check: If superheat is high, turn TXV adjustment screw counterclockwise 1/4 turn at a time

What to do: If superheat is high, turn TXV adjustment screw counterclockwise 1/4 turn at a time → Inspect suction line insulation for damage → Measure temperature difference across filter drier (>2°C = blockage suspected)

Filter drier clogged

Check: Inspect suction line insulation for damage

What to do: Inspect suction line insulation for damage → Measure temperature difference across filter drier (>2°C = blockage suspected)

Field tip

Overheated suction gas causes discharge temperature to spike. Check for low refrigerant or TXV setting. Setting TXV superheat too low causes liquid slugging and compressor damage. Do not set below 5°C.

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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