BoilerFaultCodesTechnical description
Overheat
What causes this fault?
This fault occurs when the water inside the heat exchanger reaches a dangerously high temperature, triggering a safety shut-off to prevent damage. The most common reasons include a failing pump that isn't moving water away fast enough, or a buildup of debris and sludge that is restricting the flow through the system.
This issue is more frequent during the first cold spell of autumn when the heating is turned on after a long summer break, as internal parts like the pump can seize 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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