Room stat

[tickdoc]

Hi ive quite a bit of experience in servicing and fixing oil boilers as i have in the past done my oftec 101.I also have a oil pressure gague and a kane 250. My problem however is with the heating controls.I have not been out to the house but the boiler was firing but no heat in rads.He took the head of the 2 port hortmann valve and turned it manually as he didnt know it had a override manual leaver on them. He has got heat ok ,but thinks the rads cool down again about after an hour with the time clock still on, although hes not sure. What he is sure of or so he says is when he switches heating off he cant get heat back in the rads until its all completely cooled down. He says it takes forever then. They are all hortsmann controls and im thinking its the room stat and not the motorised valve,but im really not sure. Many thanks in advance.

 

[Ermintrude]

Room stat and possibly a wiring fault that runs through rads when demand off.

 

[bright spark]

On d off chance I wonder is the stat on the boiler bunched. Hits temperature, then doesn't come back on till boilers well cooled.
sounds like possible wiring/ mini valve probs there too maybe