BoilerFaultCodesYour boiler has detected an issue with the sensor that measures the temperature of the water leaving the unit, meaning it cannot safely regulate heat.
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) thermistor fault
What causes this fault?
This fault occurs when the boiler's internal computer loses communication with the sensor that monitors the temperature of the water sent to your radiators. The most common reason is that the sensor has either failed electrically due to age or has developed a loose connection, preventing the boiler from knowing if it is overheating. To prevent damage, the boiler will shut down immediately until the sensor is replaced or repaired.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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