High
0C on Viessmann Vitodens 111-W

Your boiler has shut down because the electrical power coming into it is too weak or unstable to run safely.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

What the manual says

Manufacturer manual

Burner fault. Mains voltage is too low. Check the power supply.

From this model's manual
Verified against the Viessmann Vitodens 111 W installation & service manual, page 55.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This fault occurs when the boiler's internal computer detects that the incoming electricity supply has dropped below a safe working level. The most common reason is a problem with your home's electrical circuit or a failing component on the boiler's main control board that can no longer process power correctly.

This issue can occasionally trigger during peak winter months if the local electrical grid is under heavy strain or during stormy weather that causes fluctuations in power stability.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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