BoilerFaultCodesWhat the manual says
Manufacturer manualWater shortage, temperature rise too quick, Pump blocked, insufficient pump output, air in appliance, plant pressure too low, flow and return NTC interchanged
What causes this fault?
This fault occurs when the heat inside the boiler builds up much faster than the water can carry it away to your radiators. The most common reasons are a pump that has failed or become stuck, a significant blockage of sludge in the pipework, or air trapped within the system. Essentially, the boiler is forced to shut down to prevent itself from overheating.
This issue is frequently seen during the first cold spell of autumn when the heating is turned back on after being idle all summer, which can cause the pump to seize.
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 F.24: no call-out fees, no surprise bills.
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