BoilerFaultCodesTechnical description
Open circuit between PCB terminals 23-24
What causes this fault?
This fault occurs when the boiler's main control board loses the electrical signal from the flow thermistor, which is the component that monitors water temperature. The most common reason is a physical break in the internal wiring or a sensor that has reached the end of its life and can no longer transmit data. Without this reading, the boiler shuts down as a safety precaution because it cannot tell if the water is getting too hot.
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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