BoilerFaultCodesYour boiler has detected a faulty internal temperature sensor, which means it cannot safely measure the heat of the water and has shut down as a precaution.
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 short circuit – check/replace connections/thermistor
What causes this fault?
This fault occurs when the boiler's internal computer receives an incorrect electrical signal from the flow thermistor, which is the component that measures water temperature. The most common reason is that the sensor has developed an internal electrical short or the sensitive wiring connecting it to the main control board has become damaged or loose. Because the boiler no longer knows how hot the water is, it shuts down immediately to prevent overheating.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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