BoilerFaultCodesYour boiler has stopped working because it cannot light the flame or keep it burning properly.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: The pilot flame has failed.
What causes this fault?
This fault occurs when the boiler's control system attempts to light the burner but fails to detect a stable flame after several attempts. The most common reasons are worn-out ignition components that can't create a spark or a faulty sensor that fails to tell the boiler the flame is actually lit.
DIY fix possible
Check if your gas credit has run out or if other gas appliances in your home are workingPress and hold the reset button (the flame symbol with a cross) for 5 secondsWait 15 minutes and try resetting a second time if it fails again
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 F.21 — no call-out fees, no surprises.
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Vaillant Ecomax Pro 828E 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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