Lennox F2

Medium

Mini-Split MWM/MPA (Außeneinheit) — Outdoor ambient sensor (T4) error — voltage outside 0.06-4.94V range.

Lennox F2: Outdoor ambient sensor (T4) error — voltage outside 0.06-4.94V range. This fault usually isn't an immediate stop, but should be checked soon.

Possible causes

Sensor connection loose/faulty or sensor resistance out of spec.

Check steps

Check sensor connection, compare resistance with reference table.

Affected parts

T4-Fühler

Safety note

Isolate power before testing.

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 Compressor discharge sensor (T5) error — voltaF3 High or low voltage protection active.E5