Moving Cylinder, new pipework size.

[Greenbeast]

I'm planning to move my DHW cylinder from a first floor bedroom to a ground floor bathroom.
I intend to take the pipework from the exiting location up through the roof and down again.

It is currently a gravity hot water loop and pumped CH, but obviously i'll be moving to fully pumped (S-Plan).

Does the Hot water loop need to be 28mm all the way through the house?
The reason i ask is two-fold, obviously 28mm pipe and fittings are more expensive but also at some point i intend to replace the boiler and site the new one next to the cylinder, in this instance i'd like to re-use the pipework i'm installing now to plumb the boiler into the CH circuit.

The Current boiler is an ancient thing rated at 15kW (i believe)

Current System

Proposed new layout

Thanks for any help[/img]

 

[clf-gas]

22mm if your going fully pumped.

 

[Greenbeast]

thanks that's just what i wanted to hear

That'll transfer heat away from the boiler quick enough and be fine for a circa 22m run to the coil?

 

[Agile]

Very important and often overlooked is that the cold feed to the cylinder should be in 28 mm!

I think that used to be in a BS some while ago but its usually overlooked.

Tony

 

[Greenbeast]

you mean the cold feed from the cistern in roof to bottom of cylinder?

thats a bit awkward, i'm planning to run just 2 extra pipes as i have a 22mm pipe running that way already, the three 22mm pipes would be DHW flow & return and cold feed to cylinder

 

[Agile]

Yes, thats what I mean!

Obviously its up to you!

But if you have a complicated route with many elbows then it gets worse. If you want to be able to take a good flow rate and avoid any problems later its far better to have a 28 mm feed as recommended.

If you must stick to your 22 mm then you will be the same as probably 90% of homes where its undersized.

Tony

 

[Greenbeast]

It's looking like a run of 20m with 5-7 elbows for cold down to cylinder

 

[doitall]

Strangely enough the head/pressure will actually increase by lowering the cylinder.

Stand back and wait for the flake

 

[swidders]

Strangely enough the head/pressure will actually increase by lowering the cylinder.

Stand back and wait for the flake

How does that happen then?

 

[numpty1]

Stand back and wait for the flake

IS THAT CADBURYS or did you mean flak how you doing john
hopefully retirement is treating you well.

 

[doitall]

Stand back and wait for the flake

IS THAT CADBURYS or did you mean flak how you doing john
hopefully retirement is treating you well.

Retirement is brilliant, don't know where the time goes.