BoilerFaultCodesWhat the manual says
Manufacturer manualoverheat lockout
What causes this fault?
This fault occurs when the water inside the boiler gets too hot, causing a safety sensor to trip and shut the system down to prevent damage. The most common reasons are a pump failure that stops water from moving or a blockage within the pipework that restricts flow. In some cases, the sensor itself may have developed a fault and is incorrectly reporting a high temperature.
This issue is more frequent when the heating is first turned on after summer, as pump components 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.
Avoid the next call-out bill
A cover plan would handle faults like F5: no call-out fees, no surprise bills.
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