BoilerFaultCodesWhat the manual says
Manufacturer manualInterruption of gas supply or ignition failure (5 attempts)
What causes this fault?
This fault occurs when the boiler has tried to ignite five times but failed to detect a flame, causing the system to shut down for safety. It is most commonly caused by an interruption in the gas supply, a blocked burner, or a worn-out spark electrode that can no longer create a strong enough light. In some cases, a faulty internal sensor may simply fail to 'see' the flame even if the boiler has actually lit.
This fault is frequently seen during extreme cold snaps when the external condensate drainage pipe freezes and backups, preventing the boiler from completing its ignition cycle.
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 E133: no call-out fees, no surprise bills.
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