BoilerFaultCodesYour boiler has detected a faulty internal temperature sensor, which means it cannot accurately measure how hot the water is and has stopped running for safety.
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 sensor defective
What causes this fault?
This fault occurs when the boiler's internal thermometer, which monitors the temperature of the water leaving the unit, fails or sends an incorrect signal to the control board. The most common reason is that the sensor has physically degraded over time or suffered an electrical short, meaning the boiler can no longer safely regulate its heat output. In some cases, the issue may also be caused by damaged or loose wiring connecting the sensor to the main computer.
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 E2 — 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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