Chris
No it doesn't seem to run on when drawoff of hot water is stopped, and I'm 90% certain it has tripped when we have been out of the house...
I had never really thought about it before but we do have TRVs on all radiators (I know thats bad but it was like it when we bought the house)...
I have a Eurocombi SX 20 MFFICE and added a radiator about a month ago followed by a dose of Protex sludge remover, followed by inhibitor.
All has seemed fine for a couple of weeks but now the boiler has a couple of odd symptoms....
1. It has appeared to overheat 4 times today and tripped...