hi again reff my thread on 29 nov cold water header tank on the central heating blow off pipe permanently putting hot water back into the header tank we called the heatcall enginer out and he said it was a sticking valve which he said he fixed and put the top back on the header tank now we are getting water in the bedroom ceiling and when i went to investigate it was coming out of the averflow pipe where the jount was not a good fit so i pushed it together to stop it leaking until i get a new conector but now we are getting steam coming out of the overflow pipe outside so not fixed at all still putting water back into the header tank hot loosing my faith in heatcall 
