BoilerFaultCodesWhat the manual says
Manufacturer manualHotwaterhandlingmode:Burnerignition
From this model's manual
Verified against the Vaillant Ecotec Plus 615 installation & service manual, page 38.
What causes this fault?
This code appears when the boiler detects a demand for hot water and is physically firing up the burner to meet that request. It is a normal part of the start-up sequence and indicates that the internal components are working correctly to heat your water. You will typically see this briefly on the display every time you turn on a hot tap or shower.
DIY fix possible
This fault may be fixable without an engineer. Check your manual first.
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