Medium
453 on Viessmann Vitodens 050-W B0KA-30-M

The boiler's internal parts have lost step with each other during start-up or operation, so it has paused to protect itself, and this often clears after a simple restart.

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

Synchronisation error, sequence

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.

DIY fix possible

Switch off the boiler at its on/off switch and at the fused spur or isolator, then wait at least 5 minutes.Switch the power back on and wait for the boiler to finish its start-up sequence.Check the pressure gauge on the front of the boiler is between 1 and 1.5 bar, and top up with the filling loop only if it is low and you know how to do it safely.If the code returns, stop resetting it and book a Gas Safe registered engineer.

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Related fault codes

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

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