CH pipework question

[jeeves]

Hi,

I need to install the pipework for central heating in my house - an average 3 bedroom house. We hope to add an extension which will hopefully add a 4th bedroom and downstairs room (garage conversion).

Sadly, the downstairs is concrete floor, so I was thinking of running a 22mm ring upstairs and branching down in 15mm in 2 places to feed the downstairs radiators.

I have included a diagram:

View media item 2931
Is this ok? Will the downstairs radiators get hot? Not fully decided on a boiler as yet, would like a combi which will be fitted by an RGI, but I need to get the pipework down so we can decorate etc.

Thanks in advance

 

[seco services]

hope your not piping it as you've done the drawing.

is the rgi happy for you to install all the rads etc and decorate before boiler go's in ?

 

[ChrisR]

You've sort of drawn a "one pipe" system, instead of "two pipe".
Think of it as rads being 12Volt bulbs. You need 12V and 0V to go to every radiator.

 

[jeeves]

Thanks for the replies, sorry the diagram is a bit rough!

I've made a slight amendment to the diagram:
View media item 2932
So, from what you're saying Chris, the 15mm radiators are still not correct in the 2nd diagram?

 

[seco services]

its all wrong the black line should be two pipes.and the red lines should be one of each of the black

 

[jeeves]

I understand now, it makes sense at last! So the 22mm doesn't need to loop at all just 2 runs of it, one for flow and one for return, dropping to 15mm for radiators (1 from the flow and 1 to the return)?

Also is it ok to run 2 radiators as in the diagram in series, so :

22mm flow > 15mm radiator 1 > 15mm radiator 2 > 22mm return

Thanks for your patience!

 

[seco services]

you want all rads like this. bottom pic

http://www.diydoctor.org.uk/project_images/centralheatingsystems/ch.jpg

 

[ChrisR]

So the 22mm doesn't need to loop at all just 2 runs of it, one for flow and one for return, dropping to 15mm for radiators (1 from the flow and 1 to the return)?

Yes

Also is it ok to run 2 radiators as in the diagram in series, so :

22mm flow > 15mm radiator 1 > 15mm radiator 2 > 22mm return

No. If they were bulbs they'd be getting 6 volts each,......

You can get away with it if they're very small rads, but leads to balancing problems and saves very little pipe, if you draw it out.

Best way is "Reverse return", which I'm sure I've drawn before - try a search.

 

[jeeves]

Thanks Chris, something like this then:

View media item 2933

I found this picture on reverse return:

Is that what you mean?