BoilerFaultCodesYour boiler has detected that the flame has gone out or isn't burning correctly during operation, causing the system to shut down for safety.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Ionisation current
What causes this fault?
This fault occurs when the boiler's internal sensor can no longer detect a steady flame while the burner is active, leading the system to shut down for safety. The most common reasons are a worn-out sensing probe that can't 'see' the fire, a blockage in the gas supply, or an incorrect mixture of gas and air preventing a stable burn.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like 1-C1 — 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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