Medium
85 on Viessmann Vitodens 200-W B2KB-30

Your boiler has detected a problem with the sensor that measures the temperature of your hot water cylinder, so it may not be heating your hot water properly, but your central heating and the boiler itself are usually 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

See chapter "Fault messages".

From this model's manual
Verified against the Viessmann/Viessmann Vitodens 200 W B2hb B2kb 5792013 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

20View →21View →

All 89 fault codes on the Vitodens 200-W B2KB-30

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

9A9b9C9E9F10181920283038505158597071737475768080/EE8181/EE8282/EE8384909192939495969899A3A7A9B0b1b5b7B8bFC1C2C3C4C5CdCFd3d4d5d6d7d8E0E1E2E3E4E5E7E8E9EAEbECEdEEEFF0F1F2F3F8F9FAFbFCFdFEFF

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