BoilerFaultCodesYour boiler has detected an issue with the sensor that monitors the temperature of the water leaving the unit, causing it to shut down 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: Primary (flow) sensor fault
What causes this fault?
This fault occurs when the boiler's control board loses communication with the sensor that monitors the heat of the water leaving the unit. The most common reason is that the sensor has physically failed or developed a loose connection, meaning the boiler can no longer safely verify the water temperature. To prevent overheating, the system automatically shuts down until the faulty component is replaced.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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