BoilerFaultCodesYour boiler has stopped working because an internal temperature sensor is failing to send information to the main control board.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Primary thermistor open circuit.
What causes this fault?
This fault occurs when the boiler's main control board loses communication with the temperature sensor that monitors the primary water flow. The most common cause is a complete failure of the sensor’s internal components, but it can also be triggered by a loose connection or damaged wiring. Because the boiler no longer knows how hot the water is, it shuts down as a safety precaution to prevent overheating.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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