BoilerFaultCodesTechnical description
Set the air according to the instructions of the manual or replace
What causes this fault?
This fault occurs when the boiler's internal computer detects that the flame is not burning steadily or efficiently. It is usually caused by a blockage in the fuel nozzle, a worn-out component in the air supply system, or a dirty sensor that can no longer 'see' the flame effectively. When the air and fuel mix is incorrect, the boiler enters a safety mode to prevent damage or soot build-up.
This issue often surfaces during the first cold snap of autumn when the boiler is worked harder after sitting idle all summer, allowing old fuel or debris to clog the nozzle.
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.