High
Pilot does not light on Glow-worm Ultimate3 Combi

Your boiler is failing to start up because the small ignition flame is not lighting correctly.

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

Check for pilot jet blockage, incorrect electrode adjustment. Check continuity of pilot solenoid between EV1 and COM.

From this model's manual
Verified against the Ultimate 70ff 80ff 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 gas valve opens, but the tiny pilot flame fails to ignite or be detected. The most common reasons are a buildup of soot or debris blocking the small pilot hole, or the ignition spark being too weak to catch the gas.

This issue is more frequent after summer periods of inactivity, as debris or spiders can settle in the pilot assembly while the boiler is not in use.

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

A cover plan would handle faults like Pilot does not light: no call-out fees, no surprise bills.

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