DIY Doctor UK DIY Forums

hi mate just read a post were u advised someone not to tee in to 8mm or 10mm minibore to fit a rad cause the rad wud not work im helping a freind wi sum work on his house an he wants a rad fitted into the converted garage the easiest run wud be to tee into the 10mm feeds from the ceiling above n run down wall (studded wall that is ) i assumed wi the pipework running downhill there wudnt be a problem but wud appreciate your advise b4 i carry out the work THANX bazza

Hi I know you have asked Htg Engineer, but I can also give an explanation.
10mm pipe work can only carry enough water to heat a single radiator, by the time the water feeds through the 1st radiator there is insufficient capacity to feed a second. By the way the garage maybe below and you think as it’s down hill it should be ok, but only one pipe is down the other is the return and that must go back up! Think also what you are doing to the poor pump, try blowing down a straw and you will feel something at the other end of the straw if you place your hand there. Now imagine the straw is several meters long, blow down that, there is the same amount of air going down the first part of the straw but it wont come out of the other end. It will run out pressure before it gets to the end, same principle in central heating. Plastic pipe; maximum radiator output run in 10mm is 1.5Kw, copper pipe; 2Kw.
Hope this helps.

THANX 4 reply ill now tee into the 22mm f&r CHEERS