High
0A on Viessmann Vitodens 111-W

Your boiler has detected an issue with the gas pressure or a component failure and has shut down as a safety precaution.

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 control switches to lockout

From this model's manual
Verified against the Viessmann Vitodens 111 W 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.

What causes this fault?

This fault occurs when the boiler's internal safety sensors detect that the gas pressure is either too low or fluctuating, preventing the burner from staying lit. It is often caused by a failing gas valve that can't regulate the flow properly or worn ignition electrodes that are struggling to spark. In some cases, the main control board has developed a communication error and can no longer safely manage the combustion process.

This fault can be more frequent during extreme cold snaps when high local demand for gas can cause drops in mains pressure, or when debris in the gas line settles during the first heavy use of the winter.

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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Avoid the next call-out bill

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