BoilerFaultCodesYour boiler is struggling to burn fuel correctly because the balance of air is incorrect or a sensor is faulty.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Set the air according to the instructions of the manual or replace
What causes this fault?
This fault occurs when the boiler's internal computer detects that the flame is not burning steadily or efficiently. It is usually caused by a blockage in the fuel nozzle, a worn-out component in the air supply system, or a dirty sensor that can no longer 'see' the flame effectively. When the air and fuel mix is incorrect, the boiler enters a safety mode to prevent damage or soot build-up.
This issue often surfaces during the first cold snap of autumn when the boiler is worked harder after sitting idle all summer, allowing old fuel or debris to clog the nozzle.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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A boiler cover plan would cover faults like Green blinking light — 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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