Medium
A3 on Viessmann Vitodens 100-W B1HC-19

Your boiler has detected that a temperature sensor inside the exhaust system is not sitting in the correct position.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

The flue gas temperature sensor is positioned incorrectly

From this model's manual
Verified against the Viessmann/Viessmann Vitodens 100 W B1hc B1kc 19 35 installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

A2View →A4View →F3View →

All 29 fault codes on the Vitodens 100-W B1HC-19

Seeing a different code? Every code this model can display, in one place.

0C5A101830385051525859A9b0b7b8E3E5F0F1F2F3F4F8F9FAFCFdFF

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