DIY Doctor UK DIY Forums

Posted: **Mon Jun 21, 2010 10:29 pm**

can anyone tell me if you need to make the hot supply to outlets half inch when changing to a combi boiler

Posted: **Tue Jun 22, 2010 5:24 pm**

It would not be usual to down size the pipe simply because of fitting a combi boiler. If you are changing pipework, use 15mm instead of 22mm.

Posted: **Tue Jun 22, 2010 10:37 pm**

It is best to, as the supply to the boiler is 15mm, having a 15mm draw off, reduces the heat loss. As you cannot get more water out than you put in, there'll always be cooler water in the 22mm pipework.

htg

DIY Doctor UK DIY Forums

do you change hot pipe size when changing to a combi boiler

do you change hot pipe size when changing to a combi boiler