BoilerFaultCodesYour boiler has stopped working because one of its internal temperature sensors has lost connection or failed.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Return–NTC open circuit
What causes this fault?
This fault occurs when the boiler's control board can no longer detect a signal from the sensor that monitors water returning from your radiators. This is usually caused by a failure of the internal thermistor component or a loose electrical connection between the sensor and the main circuit board. Without this data, the boiler cannot safely regulate its temperature, so it shuts down as a precaution.
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 F.1 — 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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