working on a loft job in a bungalow. There is a cwc and header tank in the loft space with a cylinder and glowworm spacesaver boiler on the ground floor. All the pipes for the rads in the bung come up into the loft space and then drop down the walls to feed the rads on the ground floor. A ll these pipes are fed in 15mm pipe and not 22mm. Six rads are to be added in the conversion and we were just wondering how would be the best way to pipe these up. We can branch off the current pipe runs to each radiator in the loft but were worried the extra rads would struggle due to the 15mm pipe. other than that could we connect nearer the in 22mm and run e a seperate circuit. Any information/advice much appreciated.