BoilerFaultCodesYour boiler is failing to light the gas even though it is trying to start up.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Refer to fault finding section on Page 30 (displayed when control fails to detect flame after ignition attempts).
What causes this fault?
This fault occurs when the boiler tries to start but can’t establish a steady flame to begin heating. It is usually caused by a worn-out ignition part not creating a spark or a gas valve that isn't opening properly to let fuel into the burner. Over time, soot or wear on the internal sensors can also prevent the boiler from 'seeing' the flame even if it has lit.
DIY fix possible
Check that your gas emergency control valve is in the 'On' positionCheck if other gas appliances in your home, like a hob, are working correctlyPress the reset button once 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 A02 — no call-out fees, no surprises.
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Potterton Envoy 30 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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