Thanks Jazzcricket, that is reassuring. its only a small 2 bed flat with 6 medium size P+ off the one loop flow and return and one rad on its own flow and return going the other way. The system is fully pumped and Ive been recommended the potterton 33 HE as part of the deal, so probably a bit...
Thanks Jackrae, any thoughts on using 15mm throughout, that's on flow, return and tee offs to and from rads. 22mm is an option but harder to fix pipes behind extended skirting etc.
I've tried a search through the forums and wiki and I'm sure this is an on-going subject. the question is, does the plastic pipe inserts reduce the flow and return from the radiators substantially. I was told by the pipe supplier in the store and also by a heating engineer that I can use 15mm...