BoilerFaultCodesYour boiler has lost its ability to accurately measure the temperature of the water circulating through your radiators, causing the system to stop working for safety.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Central heating thermistor sensor fault
What causes this fault?
This fault occurs when the internal sensor responsible for monitoring your radiator water temperature fails or provides an unreadable signal. The most common reason is that the sensor has physically degraded over time or suffered an electrical short, meaning the boiler can no longer safely regulate heat levels. In some cases, the issue may stem from loose or damaged wiring that prevents the sensor from communicating with the main control board.
This fault often appears at the start of autumn when the heating is first switched on after a long summer break, as the sudden demand can cause an aging sensor to fail.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
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