Central heating pipework advice

[tucker]

I need a bit of advice before I make some alterations to my central heating pipework.

The current arrangement is a closed system on a combi boiler, with the flow and return pretty much all using 15mm copper pipe except the first few metres upstairs which is 22mm.

I am competent with plastic pushfit and have added and replaced rads etc.

It runs ontop of the joists into the far bedroom, does a u-turn and back. All the feeds off to the upstairs and downstairs are then on 10mm pipes.

I have built a single storey extension and I want to put a big double rad in there, by extending the flow and return loop into the extension and tee off with 10mm to the new rad.

The current set up has, what looks like a stopcock, with the handle removed, at the point where the flow turns into the return. I am guessing this stopcock has been left open a small amount incase all the rads are turn off? It doesn’t appear to be a bye pass valve as such?

My question is, what will the stopcock be there for? Do I need to replicate this, as I will be removing it.

When I run the flow to my final rad, do I need a separate link back to the return pipe or can I just allow it to flow through the rads (as long as they are not all off at the same time, it couldn’t cause a problem, could it?).

Can any advise?

 

[Puddle]

The valve you mention and pipework sounds like it is an end on circuit by pass,for the reasons you state,you can remove valve and the ends you are left with can become your flow and return to the new radiator,when you fit rad connect up flow and return to radiator then, loop both pipes together again and refit the valve to make new by pass between new last rad
You should not do away with by pass and not make any of the rads a by pass,I know it is done,but can cause problems,a proper by pass in the system should be fitted to allow thermostatic valves to be fitted were ever
Your system works well now with this by pass in why rock the boat and cause possible other problems by changing

 

[tucker]

Thanks v.much for that.

I asked a friend of a friend who fits C/H fitter the same query last night. I now have two different opinions. He said do away with it!

I didn't explain that the pipework was installed for the previous boiler which I got updated 3 years ago. I was reading the manual for the current one and it refers to the bypass valve as being optional (unless all rads have thermo valves and at least one won't) and says the boiler itself has a bypass built in.

At present all the rads are good, bar the last one on the flow. I am not sure if it's because the bypass is reducing the flow to it or, something I also plan to alter, the run using 10mm is far too long (about 20 feet).

I was inclined to replicate the bypass. My only concern is that I can envisage the new end rad might not work so good if the flow can bypass the 10mm feed to that rad by taking the 15mm route via the bypass?