BoilerFaultCodesYour boiler has lost its ability to measure the temperature of the water leaving the unit, meaning it cannot safely regulate the heat.
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 internal sensor responsible for tracking the temperature of the water leaving your boiler has failed or is sending garbled data. The most common reason is that the sensor's electrical resistance has drifted out of range due to age, or a loose connection in the wiring is preventing the control board from receiving a steady signal.
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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