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Viessmann fault code

Viessmann Fd: burner control unit fault

Engineer only

Viessmann describes Fd on Vitodens 100-W (B1HC/B1KC) boilers as: burner control unit fault.

What you can safely do

There is nothing you can safely do yourself with this one. Leave the boiler off and book an engineer.

Find a Gas Safe engineer near you Opens the official Gas Safe Register search.

Applies to: Vitodens 100-W (B1HC/B1KC). Codes can differ between models, so check your manual.

From Viessmann's own fault tables. Your model name is usually on the front of the boiler or in the user manual.

Model	Meaning
Vitodens 100-W (B1HC/B1KC)	Burner control unit fault

Can I fix Viessmann Fd myself?

No. It needs a Gas Safe registered engineer to diagnose. Tell them the exact code and your boiler's model name.