BoilerFaultCodesYour boiler is failing to start up because the small ignition flame is not lighting correctly.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Check for pilot jet blockage, incorrect electrode adjustment. Check continuity of pilot solenoid between EV1 and COM.
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 fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like Pilot does not light — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Glow-worm Ultimate 100ff 120ff is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
Affiliate links — we may earn a commission at no extra cost to you.