Your boiler is currently running a 15-minute cleaning and safety cycle to fill up its internal drainage system, which is a normal process after a power cut or reset.

Trap filling programme is active. The appliance remains at minimum heating output for 15 minutes to ensure the condensation trap is filled.

What causes this fault?

This code appears when the boiler needs to refill its internal reservoir that collects waste water, which typically happens after the power has been turned off or the system has been reset. To ensure no exhaust gases escape through the drainage system, the boiler stays at a very low power level for fifteen minutes to safely generate enough condensation to fill the trap. Once this automatic safety cycle finishes, the boiler will return to its normal heating settings without any intervention needed.