Viessmann 3A

High

Vitocal — Open circuit, evaporator air-inlet temperature sensor — no room heating/cooling, only defrosting possible.

Viessmann 3A: Open circuit, evaporator air-inlet temperature sensor — no room heating/cooling, only defrosting possible. This fault noticeably affects operation.

Possible causes

NTC sensor (15 kΩ) at the evaporator open circuit.

Check steps

Check resistance (NTC 15k) at the sensor connection, replace sensor if needed.

Affected parts

Verdampfer-Lufteintrittsfühler

Safety note

Isolate power before testing.

Source: Viessmann Vitotronic 200 Typ WO1C Serviceanleitung für die Fachkraft (2017-01), "Übersicht der Meldungen" §Störungsbehebung, Art.-Nr. 5813961

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

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