BoilerFaultCodesYour boiler has detected a problem with the sensor that monitors hot water temperature, which may mean you have no hot water or the temperature is inconsistent.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Not water thermistor fault
What causes this fault?
This fault occurs when the boiler's control board can no longer read a reliable signal from the sensor that monitors your hot water. The most common reason is that the internal components of the sensor have degraded over time or the electrical connection has become loose or corroded. Because the boiler doesn't know how hot the water is, it stops heating it as a safety precaution to prevent scalding.
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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