Its an internal boiler. You could be right about the post purge kit, there was some discussion about whether to replace it or not. It was making a bit of noise. Simple enough to replace anyway.
Thanks for all your help, much appreciated
stan
we have just had our 15/19 serviced, and the boiler now runs continually at a low level, putting my hand over the flue and there is always warm air coming through it.
even if I turn the water heating temp down to zero and the same for the heating and indeed turn them to off on the timer it...