My Keston Celsius 25 is occasionally failing to light and going into lockout. (Red light giving two flashes, none of the 1-4 lights lit)
It only seems to have started doing it during this spell of warm weather. You can hear the ignition circuit fire, and the "whumph" sound as the burner lights, but then it gives up and tries again. So I presume either it has lit but is failing to sense that it's lit, or that for some reason it isn't sustaining the flame.
It's nearly 2 yrs old and has worked fine up to now.
Anyone got any experience of this?