BoilerFaultCodesTechnical 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 is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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