New Central Heating Pipes

[dc_oldridge]

Hi, i currently have a combi boiler Worcester Bosch Greenstar 4000 in my downstairs utility room. Flow and return pipes leave boiler then tee off with 22mm flow and return going under ground in concrete supplying downstairs radiators and 22mm going upstairs to under bathroom floor and running down landing with 15mm tee offs supplying upstairs radiators. 4 rads down and 4 rads upstairs. I have a leak on downstairs pipework im guessing under the concrete. Im reluctant to dig up all downstairs so was wondering if i capped off the 22mm flow and return pipes going under ground and made them redundant and tee’d off the upstairs 22mm and ran 22mm under landing floor with 15mm drops down to each downstairs radiators would this work.
Kind Regards
Daniel

 

[Jurassicspark]

What pointed out that you have a leak? I'm guessing a drop of boiler pressure. If so, how much/ often does it drop by?

How do you know the leak is downstairs?

 

[dc_oldridge]

Boiler pressure dropping to zero every few hours, faster after heating switched off, topped system up to 1.8 bar isolated return and flow left over night no drop. Open return and flow pressure dropped to zero. Checked all radiator valves etc and visible pipework no leaks. No signs of leak from above ie. Staining on celings etc. Assuming it is leaking under the concrete and not visible.

 

[dc_oldridge]

I have fitted some isolation valves on the 22mm flow and return for downstairs so i can prove if up or downstairs, but haven’t tested yet

 

[oldbutnotdead]

The theory of your plan is fine but how well it works depends on the rad sizes. Have a Google for thermal capacities of copper tube but you need to be a bit careful if your system runs at condensing temperatures (ie 50-odd deg c at the rads).