Bosch A01 (5420)

Medium

Compress — Temperature sensor TR4 — open circuit.

Bosch A01 (5420): Temperature sensor TR4 — open circuit. This fault usually isn't an immediate stop, but should be checked soon.

Possible causes

Sensor TR4 or signal cable open.

Check steps

Check sensor TR4 & signal cable.
Compare resistance with table.

Affected parts

Fühler TR4

Safety note

Follow F-Gas.

Source: Bosch/IVT/Buderus Compress Wärmepumpe Alarm-Tabelle (lvisawo.fi/jseducation.se resmi servis kılavuzu aynası) — Confirmed via direct PDF read p.19: code 5420, Installer, 'Warning Z1 Condensate sensor cooling mode TR4 open circuit', broken circuit (>170 kOhm).

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

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