BoilerFaultCodesTechnical description
Primary Overheat fault (water pressure, pump, sensor, or thermostat).
What causes this fault?
This fault occurs when the water inside the boiler gets too hot too quickly, triggering a safety switch to prevent damage. The most common reasons are a pump that has stopped moving the water around, a blockage in the pipework, or a sensor that is sending incorrect readings to the control board.
This issue is more frequent in autumn or winter when the heating is first switched on after a long summer break, as pumps can often seize up from lack of use.
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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