BoilerFaultCodesYour boiler has stopped working and locked itself out because it failed to light or stay lit correctly.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Boiler at lockout.
What causes this fault?
This fault occurs when the boiler's control board fails to detect a stable flame after several attempts to ignite. The most common reasons are a worn-out ignition spark that can no longer light the gas or a dirty sensor that cannot 'see' the flame even if it is burning. In some cases, it may be caused by an inconsistent gas supply or a failing gas valve that isn't opening correctly.
DIY fix possible
Check if your gas supply is turned on (try another gas appliance like a hob).Press the reset button once to see if the boiler restarts.Ensure your condensate pipe has not frozen if it is a very cold day.
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 8 (Flashing) — no call-out fees, no surprises.
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Potterton Envoy 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.
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