Hi - I have a Vaillant Ecotec 28HE Boiler installed and following revamping of ground floor layout need to add an additional radiator. The existing system is 22mm flow and return pipes upto and within the first floor void with individual Tees and 15mm pipework connections to first and ground floor rads. The new rad will be positioned approx 2M from the boiler. Will there be any potential problems with Teeing into the flow and return pipes approx 700mm above the boiler connection points. If ok, with rad being so close to the boiler would 10mm copper microbore instead of 15mm help with balancing of the system? or make no difference?.