DIY Doctor UK DIY Forums

Hi I am just having installed a pressurized hot water cyclinder using a system boiler.My installer wants to use 15mm pipe to feed two baths after an initial run of say 1meter from the tank of 22mm .i have a feed straight from the water mains nearby that then goes into 22 mm to feed the cylinder why cant we carry that on through to the baths in 22mm .i am thinking that if both baths were filling at the same time it will be slow or at least slower than 22mm.I have seen previous posts but that was assuming using a combi boiler with a 15mm feed , i have a 22mm feed to tank .Many thanks

I would expect that under mains pressure 15mm would be reasonable, but this obviously depends on the mains supply. Has your plumber given reasons for his desire to use 15mm? It may just come down to cost, in which case if you are the customer are willing to pay extra for a chance at a better end result I would expect the plumber to be willing to do it.

The fitter just said that it will be ok, I did express more than once that perhaps 22mm all the way threw would be best but i obviously assumed that he knew best.But now having tried the end result i am not impressed with the fill times .I am in a position before the tiles go on to change it just wanted to no if the fill times would be quicker in 22mm

You can obviously fit [b]more[/b] water in a 22mm pipe than you can in a 15mm pipe.