BoilerFaultCodesYour boiler has detected that a temperature sensor is stuck or faulty, meaning it cannot accurately monitor the water temperature to operate 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 NTC reports constant value (stuck at) | Flow NTC is defective
What causes this fault?
This fault occurs when the boiler's internal computer notices that the flow temperature sensor is sending the exact same reading regardless of whether the burner is on or off. The most common reason is that the sensor has suffered an internal electrical failure or has become covered in limescale, preventing it from detecting actual changes in water temperature.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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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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