Excellent reference, much appreciated! Not entirely satisfied with the situation here but becoming much more familiar with the inside of the airing cupboard (my wife believes I'm having an affair!).
Why is the sync motor too hot to touch when both CH and HW are resting? Please bear with my thinking out loud, I'd appreciate comments. Installation c30 yrs old.
CH wasn't turning on, either to timed or override control (Honeywell 4033) however a Vmeter showed setting the CH, HWon and HWoff...