Lennox P4

Medium

Mini-Split MWM/MPA (Außeneinheit) — High temperature sensed at compressor discharge line.

Lennox P4: High temperature sensed at compressor discharge line. This fault usually isn't an immediate stop, but should be checked soon.

Possible causes

Low refrigerant charge, high pressure ratio, or compressor overload.

Check steps

Check refrigerant charge and operating pressures.

Affected parts

Verdichter

Safety note

Hot discharge line — burn hazard.

Source: Lennox Mini-Split Systems Service Manual — Indoor and Outdoor Unit Error Codes (Corp. 1816-L7, 2018), "Extended Reference Guide - Outdoor Unit Error Codes" §4 and "Indoor Unit Error Codes" §5

Reviewed by Anıl Güzeldemir — in the refrigeration machine room since 2006, developer of Enthalio.

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Related fault codes

Outdoor EEPROM malfunction — main control boarE0 Communication error between outdoor unit main E3 Indoor unit coil outlet temperature sensor (T2E4 Outdoor coil sensor (T3) error — voltage outsiF1 Outdoor ambient sensor (T4) error — voltage ouF2 Compressor discharge sensor (T5) error — voltaF3