BoilerFaultCodesTechnical description
Appliance on but not operating during demand
What causes this fault?
This fault occurs when the boiler is receiving an electrical signal to start, but the internal sequence to light the flame is interrupted. It is often caused by a lack of spark from the ignition electrode or a failure in the internal fan which clears waste gases. In some cases, the gas valve may not be opening correctly to allow fuel into the burner, preventing the boiler from firing up.
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.
Find a Gas Safe engineer
Search the official register →