BoilerFaultCodesWhat the manual says
Manufacturer manualDHW thermistor fault
Shared across the range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
What causes this fault?
This fault occurs when the boiler's internal computer loses communication with the sensor that monitors your hot water temperature. The most common reason is that the sensor has physically failed due to age or internal wear, though it can also be triggered by loose or corroded electrical connections between the sensor and the main control board.
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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