BoilerFaultCodesYour boiler has tried to light several times but cannot establish a flame, meaning your heating and hot water will not work.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Ignition lockout. Check: Gas present and at correct pressure; Combustion CO2 level; Flue condition; Ignition electrodes / harness / connections; Gas valve (coils 140-190Ω) / low voltage harness connection. Otherwise replace control board.
What causes this fault?
This fault occurs when the boiler's internal computer tries to start the burner multiple times but cannot detect a flame. The most common reasons are a lack of gas reaching the unit, a worn-out ignition spark, or a sensor that can no longer 'see' the flame even if it has lit.
This fault is more common during extreme cold snaps, as the external gas meter or pipework can occasionally struggle with pressure drops or frozen components.
DIY fix possible
Check if your gas meter has credit and that the gas supply valve is openCheck if other gas appliances in your home, like a hob, are workingPress and hold the Reset button for five secondsThaw the condensate pipe if it is frozen during cold weather
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 Slow flash (normally off, flashes on) — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Worcester Bosch Greenstar 24i Junior 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.