Low
425 on Viessmann Vitodens 100-W B1GA

Your boiler is having trouble connecting to the internet to set its internal clock, which may disrupt your heating schedules.

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

Time synchronisation failed

From this model's manual
Verified against the Viessmann Vitodens 100 W B1ga installation & service manual, page 63.
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

Check your home Wi-Fi router is switched on and workingMove your router closer to the boiler if possible or check for signal interferenceOpen the ViCare app on your phone and follow the prompts to reconnect your boiler to the network

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Related fault codes

421View →424View →F.94View →

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