DIY Doctor UK DIY Forums

Hi,
I have an old and tired single pipe CH system which I propose to replace with a plastic feed and return system.
The pump will have to be several metres from the boiler. I have two questions:

1: Should the pump be pulling from the boiler and pushing water along the feed to the radiators?

2: Where should the cold water feed and vent pipes connect, in relation to the pump? I've heard they should be 150mm apart, and am unsure which should come first along the flow.

Thanks for any help, Jim H.

Hi Jim....

a) Yes... The pump should pull from the boiler.

b) Picture the letter "H" in your head as a piece of pipe.

.......The horizontal between the two verticals should ideally be 150mm apart

.......The bottom left pipe should be the pipe going from the boiler

.......The top left pipe should be the "open vent" pipe going to the vent in the tank

.......The top right pipe should be the "cold feed" pipe coming from the tank

.......The bottom right pipe should go to the "inlet" of the pump (Ideally within 250mm)




From the pump; you would then connect into your motorised valves (if you have them) and then to the radiators.

Hi,
Thanks for the clear explanation. That's what I wanted to know.

Regards, Jim