BoilerFaultCodesTechnical description
The diagnostics will indicate the nature of the fault to assist a speedy and effective repair
What causes this fault?
This fault occurs when water backs up within the system because it cannot drain away properly, triggering the safety float switch to cut off the boiler. The most common reasons are a blockage in the internal condensate trap, a buildup of debris in the drain pipe, or a failure of the external pump that moves wastewater away from the unit.
This fault is more common during freezing winter temperatures, as the external condensate pipe can freeze solid, causing water to back up into the boiler and trigger the switch.
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 →