BoilerFaultCodesWhat the manual says
Manufacturer manualThis code can appear if the unit adjusts itself to the small amount of water in the installation.
What causes this fault?
This fault occurs when the boiler senses that the water inside the unit is heating up much faster than expected, which usually points to a lack of flow. This is most commonly caused by low system pressure, a blockage in the pipes, or a failing pump that isn't pushing the water around your radiators effectively. The boiler shuts down as a safety measure to prevent the heat exchanger from overheating.
This issue is frequently seen in autumn when heating systems are turned back on after being idle all summer, which can cause internal pump components 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 2F: no call-out fees, no surprise bills.
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