BoilerFaultCodesYour boiler has stopped working because one of its internal temperature sensors is unable to send a signal to the main control board.
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: NTCbroken; NTCcable broken; Defective connection at NTC Defective connection at electronics | Return-NTC cable defective/broken NTC faulty
What causes this fault?
This fault occurs when the boiler's return sensor fails to communicate the water temperature back to the main control board. The most common reason is that the sensor's internal electrical resistance has failed due to age, or the thin wiring connecting it to the computer has become loose or damaged.
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.01 — no call-out fees, no surprises.
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Vaillant Thermocompact is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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