BoilerFaultCodesTechnical description
Overheating
What causes this fault?
This fault occurs when water cannot circulate through the boiler quickly enough to carry heat away, causing the internal temperature to spike. The most common reasons are a failed pump that isn't pushing water, a blockage caused by sludge buildup, or air trapped within the system.
This issue is more frequent when heating is first turned on after summer, as the 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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