BoilerFaultCodesWhat the manual says
Manufacturer manualOverheat condition occurs
What causes this fault?
This fault happens when water inside the boiler reaches a temperature that is no longer safe, triggering an automatic shutdown to prevent damage. It is usually caused by a pump failure preventing water from moving away from the heat exchanger, or a build-up of sludge and debris that blocks the flow. In some cases, a faulty sensor might also incorrectly signal that the system is overheating.
This issue often surfaces in autumn when the heating is turned on for the first time after summer, as internal pump parts can seize 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.
Avoid the next call-out bill
A cover plan would handle faults like Lockout (Red) flashing: no call-out fees, no surprise bills.
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