BoilerFaultCodesTechnical description
Neon indicating boiler status: The preset overheat thermostat has tripped due to excessive temperature
What causes this fault?
This fault occurs when the internal temperature of the boiler exceeds safe limits, triggering a safety switch to prevent damage. It is usually caused by a failure to move hot water away from the heat exchanger, often due to a seized pump, a blockage in the pipework, or a faulty sensor misreading the temperature.
This issue often appears when the heating is first turned on after summer, as the circulation pump can seize up during long periods of inactivity.
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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