BoilerFaultCodesYour boiler's temperature sensor for the hot water storage tank has developed a fault, meaning the system cannot safely monitor or heat your hot water.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Tank thermistor fault
What causes this fault?
This fault occurs when the sensor responsible for monitoring the temperature in your hot water storage tank fails to send a reliable electrical signal to the boiler’s control board. The most common reason is the internal degradation of the thermistor or a loose connection in the wiring, which prevents the boiler from knowing how hot the water is. For safety reasons, the system shuts down hot water production to prevent potential overheating.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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