BoilerFaultCodesYour boiler is struggling to start because it cannot get a correct temperature reading from the sensor located on the outside of your house.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Burner does not start. Outside sensor fault (short circuit or lead break).
What causes this fault?
This fault occurs when the boiler loses connection with the temperature sensor mounted on the external wall of your home. It is physically caused by either a terminal failure inside the small plastic sensor box or damage to the electrical cable connecting that sensor back to the boiler's main control board. Without this reading, the boiler cannot calculate the correct water temperature and prevents the burner from firing as a safety precaution.
This fault is more common during autumn and winter, as heavy rain or freezing conditions can accelerate corrosion within the sensor casing or cause water ingress in the wiring.
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 E15 — no call-out fees, no surprises.
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