BoilerFaultCodesWhat the manual says
Manufacturer manualInsufficient system water pressure
What causes this fault?
This fault occurs when the internal sensor detects that there is not enough water inside the system to operate safely. The most common reason is a small leak in the pipework or radiators, though it can also happen if you have recently bled your radiators and haven't topped the pressure back up.
This issue often appears at the start of autumn when the heating is turned on for the first time after summer, as seals can shrink or existing small leaks become apparent.
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 AL41: no call-out fees, no surprise bills.
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