BoilerFaultCodesYour boiler has detected an issue with the air fan system and has temporarily stopped heating to prevent further damage.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Fan return flow
What causes this fault?
This fault occurs when the boiler's control system detects that the fan is spinning but sending back incorrect signals, or it isn't spinning at the speed required for safe combustion. The most common reason is an internal electrical failure within the fan motor itself or a communication glitch between the fan and the main circuit board. Without the fan functioning perfectly to clear exhaust gases, the boiler shuts down as a safety precaution.
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 S.16 — 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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