Hi, the expansion tank in my attic/bedroom was taken out and I was left without hot water and no heat to upstairs radiators. I have now put back a new expansion tank with cold water cistern feed,vent pipe and overflow pipe. What I would like to know is where do I connect the feed/outlet at the bottom of the tank to in the sytem. I have fitted a new radiator under the new tank and that is cold as well. can I connect the outlet to the cold pipe on the radiator? to top up the system. Please help.