BoilerFaultCodesYour boiler has failed to ignite, meaning it cannot light the gas to provide heating or hot water, often due to a lack of gas flow or a blocked condensate pipe.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Failure to light (could be a gas supply issue)
What causes this fault?
This fault occurs when the boiler tries to ignite three times but fails to detect a flame, causing the system to shut down for safety. The most common reasons are a temporary interruption in the gas supply, a blocked drainage pipe, or dirty internal components that can no longer create a spark.
This fault is significantly more common during freezing winter temperatures, as the external condensate pipe can freeze and cause a backup that prevents the boiler from lighting.
DIY fix possible
Check that your gas meter has credit and that the gas emergency control valve is open.If it is freezing outside, check if the white plastic condensate pipe leading outdoors is frozen and thaw it with warm water.Press and hold the 'R' or Reset button for five seconds to see if the boiler restarts.
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 E133 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
Affiliate links — we may earn a commission at no extra cost to you.