Low
F.474 on Viessmann Vitodens 100-W WB1A

Your boiler's computer system has detected a temporary glitch in its internal clock or scheduling software, causing it to stop following your programmed heating and hot water times.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

What the manual says

Manufacturer manual

Error in scheduled program run monitoring

From this model's manual
Verified against the Viessmann Vitodens 100 W Wb1a installation & service manual, page 97.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Switch off the boiler at the fused spur or mains power supply.Wait for at least 60 seconds to allow the internal processor to fully reset.Switch the power back on and check if the boiler resumes normal operation.

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