High
02 on Glow-worm Xtrafast 120

Your boiler has stopped working because the fan system cannot properly clear waste gases or bring in fresh air to burn fuel 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

Air flow fault

From this model's manual
Verified against the Glow Worm Xtrafast 96 installation & service manual, page 29.
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 fan isn't moving enough air to safely vent exhaust gases outside. The most common reasons are a build-up of dirt in the fan assembly, a blockage in the flue pipe, or a failure in the electronic switch that monitors air pressure.

This issue can sometimes appear during periods of high winds, which can create back-pressure in the flue and interfere with the air pressure sensor's readings.

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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