BoilerFaultCodesWhat the manual says
Manufacturer manualAppliance is within the waiting period of the operation block function due to water shortage (temperature gradient)
What causes this fault?
This fault occurs when the boiler's internal sensors detect a rapid rise in temperature without enough water moving through the heat exchanger to carry that heat away. The most common reason is a malfunctioning circulation pump or a blockage in the pipes, such as trapped air or a build-up of system sludge, preventing the water from flowing freely.
This issue often appears when the heating is first turned on in autumn, as circulation pumps can seize up after being inactive over the summer months.
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 S.54: no call-out fees, no surprise bills.
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