Medium
C3 on Viessmann Vitodens 200-W B2HA-49

Your boiler's control system has lost contact with one of its add-on modules, so some heating functions may not be working properly, though the boiler itself is likely still safe to use.

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

Communication error, AM1 extension

From this model's manual
Verified against the Viessmann/Viessmann Vitodens 200 W B2ha 49 60 5817254 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

C1View →C4View →

All 82 fault codes on the Vitodens 200-W B2HA-49

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

4C9A9b9C9E9F1018192028303838:≠0404448505890919293949899A3A4A7b0b1b5b7b8bAbbbCbdbEbFC1C2C4CdCFd6d7d8dAdbdCdddEdFE0E1E2E3E4E5E6E7E8EAEbECEdEEEFF0F1F2F3F6F8F9FAFCFdFEFF

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