Central Heating plan advice wanted

[frediaz]

Hello,

I am planning the piping installation in a house I am refurbishing, see the drawings of it here. I would appreciate feed-back on my plan. Ask any questions you need.

Main points:
1- I am only doing the pipework. A Gas Safety plumber will be asked to connect and commission the combi boiler.
2- I want to use 10mm pipes (the new Hep 2O ones) only because they would be easier to route in the house, unless people with experience of them have strong feelings against them. Most of these pipes are under 5 metres long except for some of the return ones which can go up to 7 metres.
3- I have not done the earth bonding yet.
4- I have not calculated the radiators output yet.
5- The house has cavity walls which have been filled with insulation. I am replacing all roof and floor insulation with the one in the current regulations.
6- There is probably no insulation in the ground floor and I am not installing any.
7- As the drawing show, I am taking 22mm pipes from the boiler up to the floor/roof space. Then they split in two branches 1 and 2 (4 radiators for each) and get as close to the radiators as possible before the 10mm pipes go down to them.
8- I will cover the pipes in the cold roof space with one layer of wool insulation.

Thanks

Untitled

• frediaz
• 17 Jun 2012
• 1

Untitled

• frediaz
• 17 Jun 2012
• 1

Untitled

• frediaz
• 17 Jun 2012
• 1

 

[kevplumb]

4- I have not calculated the radiators output yet.

thats the first thing you should do
before sizing the pipework

 

[ChrisR]

As Kev says, numbers first. Then:

there's quite a lot that's right, there's some where you're apparently "outside your knowledge".
I suggest you pay the intended boiler-fitter for an hour+ to go over some basics.
Your first diagram will cause a few sighs

Gas pipe sizing, he'll need to know before he comes to fit them..
You can present him with nearby water /CH pipes, which you can have tested first, but
-don't hang the boiler
-don't tell him what fittings to use
-don't tell him where the flue has to go
etc

If I were living there I'd go for a 28+kW boiler, for the HW, too.

 

[frediaz]

Thanks, yes it is where I am out of my depth that I am asking for advice. I have already discussed the general pipework with the plumber but I wanted external opinions and advice on the detail.
The plumber suggested microbore pipes but I always ask someone else about these. Hepworth claims that the new HEP 2O 10mm pipes are better than ordinary microbore pipes.

 

[frediaz]

If I were living there I'd go for a 28+kW boiler, for the HW, too.

My plumber mentioned this possibility bu he said that this boiler needs a flow of 12.5 litres/minute and the pressure in my house is not brilliant, he measured 10L/min at 1 bar. So he says you can install a boiler as big as you want but it will only use up more gas and will not give you more HW. That is why I come here to ask for other opinion.