BoilerFaultCodesYour boiler has detected an issue with the sensor that monitors the temperature of the water leaving the unit, preventing it from heating your home safely.
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 system receives an incorrect or missing signal from the sensor that monitors hot water leaving the unit. The most common reason is that the sensor has physically failed or developed a loose electrical connection, meaning the boiler can no longer safely regulate its temperature.
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 4.8 — 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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