BoilerFaultCodesYour boiler is trying to start up but is failing to create the spark or flame needed to heat your water.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Spark generation and ignition
What causes this fault?
This fault occurs when the boiler's control system attempts to light the burner but cannot detect a stable flame. It is usually caused by a component failure that prevents a spark from being generated, or a blockage that stops gas from flowing into the combustion chamber.
This fault can appear more frequently during the first cold snap of autumn when old electrodes or gas valves struggle to operate after sitting idle through the summer.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
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A boiler cover plan would cover faults like 84 — no call-out fees, no surprises.
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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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