BoilerFaultCodesTechnical description
Pre-circulation fault
What causes this fault?
This fault occurs when the boiler detects that water isn't moving through the unit quickly enough during its initial startup checks. The most common reasons are a build-up of sludge blocking the internal pipework or a mechanical failure of the pump that circulates the water. Because the water can't flow, the boiler shuts down to prevent the heat exchanger from overheating.
This issue often surfaces in autumn when the heating is turned back on after a long summer break, which can cause internal pump components to seize up from 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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