BoilerFaultCodesTechnical description
Overheating
What causes this fault?
This fault occurs when the internal temperature of the boiler rises above a safe limit, causing it to trip a safety switch. The most common reasons are a failed pump that isn't moving water around the system quickly enough, or a blockage caused by sludge and debris inside the heat exchanger. It can also be caused by an air lock in the pipework that prevents the water from absorbing the burner's heat.
This fault is more frequent when the heating is first turned on after summer, as pump components 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.
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