BoilerFaultCodesTechnical description
Heat exchanger blockage or pump fault (Overheat)
What causes this fault?
This fault occurs because the internal sensors have detected that the water inside the boiler is reaching a dangerously high temperature. It is usually caused by a pump failure that prevents water from moving away from the burner, or a build-up of debris that has physically blocked the heat exchanger. Because the heat cannot be carried away to your radiators or taps, the boiler shuts down to prevent internal damage.
This issue often surfaces when you first turn your heating back on in autumn, as pumps can seize up after being idle during the summer months.
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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