Medium
979 on Viessmann Vitodens 050-W B0KA-30

Your boiler is getting heating requests from two control connections at once, so it is confused about which one to follow, and it may not respond to the heating controls properly until a heating engineer checks the wiring and settings.

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

Both inputs – plug 96 and OpenTherm – are occupied and reporting a heat demand

From this model's manual
Verified against the Viessmann/Viessmann Vitodens 050 W B0ha B0ka 6194588 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

978View →980View →

All 131 fault codes on the Vitodens 050-W B0KA-30

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

78131449505758596263646768697071727374757778878995104142161163182183184299346347348349350351352353354355357359361364365366367369370371372373374375376377378379380381382383384385386387388393394399400401402403404405406408410416417418425446447448449450451452453454455456457458461462463464467468471474527528540574575576577578579682683684694738766767799980981982E10E12

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