BoilerFaultCodesTechnical description
1 Check if condensate pipe blocked/frozen 2 Check if flue blocked 3 If fault persists, contact installer
What causes this fault?
This fault occurs when the boiler's sensors detect a blockage that prevents the safe removal of exhaust gases or waste water. The most common reason is a buildup of debris in the condensate trap or a physical obstruction in the external flue pipe. If these paths are blocked, the boiler automatically shuts down to prevent dangerous fumes from entering your home or water from backing up into the internal components.
This fault is significantly more common during freezing winter temperatures, as the external condensate pipe can freeze and prevent waste water from draining away.
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.