BoilerFaultCodesYour 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.
This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.
Technical description: 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.
DIY fix possible
Wait for 15 minutes for the timer to finishEnsure any thermostat or timer is calling for heatMonitor the display to see if it returns to a normal temperature reading
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like −II− — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Worcester Bosch R30 35 And 40 HE Plus is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
Affiliate links — we may earn a commission at no extra cost to you.