BoilerFaultCodesTechnical description
Hot burner holding operation on / Cylinder charging burner on
What causes this fault?
This occurs when your boiler has heated the water to the target temperature so quickly that the heat hasn't had enough time to circulate through your radiators or hot water cylinder. To prevent overheating, the boiler temporarily lowers its flame or pauses until the water temperature inside the unit drops to a level where it can safely start heating again. It is often a sign that the pump is moving water slowly or your radiators are struggling to dissipate the heat.
This is more common during the autumn and spring when your heating is turned on but the weather is mild, meaning your home requires less heat than the boiler’s minimum output.
DIY fix possible
Check that at least one radiator with a manual valve is turned fully openEnsure your Thermostatic Radiator Valves (TRVs) are not all set to 'zero' or 'frost'Wait 10-15 minutes to see if the status changes as the water cools down