BoilerFaultCodesYour boiler started to heat up but the flame went out unexpectedly while it was running.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Loss of flame during operation
What causes this fault?
This fault occurs when the boiler successfully lights, but the internal sensors lose track of the flame while it is running, causing the system to shut down for safety. The most common reasons are a worn-out sensing probe that can no longer 'see' the fire, or an unstable gas supply that prevents the flame from staying consistent.
DIY fix possible
Check that your gas pre-pay meter has creditEnsure other gas appliances in your home are working to confirm gas supplyPress the 'Reset' button for five seconds
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 128 — no call-out fees, no surprises.
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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.
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