Medium
dE on Viessmann Vitodens 343-F WS4A

Your boiler is still producing heat, but it can't read the temperature from the room sensor for one of your heating circuits, so it is running on a less precise backup setting and may not hold your rooms at exactly the temperature you choose.

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

Control mode without room influence - Room temperature sensor, heating circuit with mixer M2 lead broken

From this model's manual
Verified against the Viessmann/Viessmann Vitodens 343 F Ws4a 5592883 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

dCView →dFView →

All 59 fault codes on the Vitodens 343-F WS4A

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

0F9A9b9C9F10182028303840485058929394A6A7b0b1b4b5b7b8bAbCbdbEbFC2CdCECFdAdbddE4E5E8E9EAEbECEdF0F1F2F3F4F8F9FAFCFdFEFF

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