BoilerFaultCodesYour boiler has detected a problem with the internal sensor that measures the temperature of the water leaving the unit, preventing it from heating correctly.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Flow Thermistor Fault
What causes this fault?
This fault occurs when the boiler's control board loses communication with the sensor that monitors the temperature of the water heading to your radiators. It is usually caused by the internal sensor failing due to age or heat fatigue, though it can also be triggered by a loose electrical connection or moisture damange to the wiring.
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 4.7 — 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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