BoilerFaultCodesYour boiler has detected a problem with its primary temperature sensor and has stopped working as a safety precaution.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Sensor fault S1
What causes this fault?
This fault occurs when the boiler's main flow sensor, which monitors the temperature of the water leaving the heat exchanger, fails to provide a consistent or logical reading. The most common reason is that the internal electrical component of the sensor has worn out or developed a short circuit, preventing the control board from knowing if the water is at a safe temperature.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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