Distribution of central heating water to rads

[Paul_Thomas]

Hi

We currently have a 10mm microbore central heating system off our aging gas boiler.
Due to a new extension and the external wall having to be removed we are going to have a new condensing combi boiler installed.

Obviously I will get a plumber in to install the new boiler but the new rads etc will be installed by me one at a time as I do each room.

I will plan on using 15mm pipe rather than 10mm microbore as I have heard this is better(??) How should I distribute this from the 22mm output pipe from the boiler, should it be through a manifold or a number of 15mm T's off the 22mm pipe?

 

[Paul_Thomas]

Can anyone offer advice on this?

 

[george792]

Run 22mm pipe from the new boiler position then you will be fine branching off with 15mm tees to the new rads.

 

[nickso]

there are ways of measuring it out properly but in general terms tee off the 22mm pipe as close to the rad as possible.

 

[Paul_Thomas]

Thanks guys.

So the 22mm pipe really needs to run around the new extension?


Am I correct in saying that I would be better using 15mm rather than 10mm microbore like the rest of the house?

 

[nickso]

ideally yes it does. especially if the new boiler is going to be at the opposite side of the house. you want at least a 22mm pipe to the extension and then branch off as close as possible to the furthest away rads otherwise you run the risk of poor flow to them.

its not a good idea to mix microbore with 15mm rad pipes as this can upset the balance of the system. i would change them all to 15mm if thats not already your plan. .

 

[Paul_Thomas]

The existing boiler is on the kitchen wall, this wall is being removed because of the extension. Obviously it's not worth re-fitting a 18year old boiler so we are having a new one in the extension.

There is no chance of me removing the existing microbore around the house, due to cost and also it works fine. The house warms up pretty quickly, even in the winter.

Would I do better to install 10mm microbore in the extension to match then? (Part of garage is being converted to bedroom plus 2 extra bedrooms above and shower room)