Medium
474 on Viessmann Vitodens 100-W B1GA

Your boiler's internal computer has encountered a software timing error or a communication glitch while trying to run its pre-set operation sequence.

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

Error in scheduled program run monitoring

From this model's manual
Verified against the Viessmann Vitodens 100 W B1ga installation & service manual, page 65.
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

Locate the power button or switch for the boiler.Turn the boiler off for 30 seconds and then turn it back on.Wait for the system to reboot and check if the code clears.

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