Just designing the layout for the C/H system in the property we're developing. It'll be the standard two pipe job.

What I was wondering is how close to the radiator can you T off. I can T off quite close but it makes it ackward for running the pipe, so I would prefer to T off further away - upto 3m for the worst case.

Also, can the bypass radiator (I'm planning on having TRVs on the rest of the radiators) by the 1st after the boiler.

Starting from the boiler you should have a flow and return, this enters the motorised valve Yplan the one port goes to the heating and the other too the cylinder.

The heating return will join the cylinder return via a tee piece, from this point back to the boiler no further tees can be fitted in the common return.

By-pass rad ? depending on the boiler and the regs an auto-bypass valve is required, and should be fitted after the pump and before the common return

Send me an email quickly and I will knock out a drawing tomorrow.

Sorry, by boiler I ment combi.

By T'ing off I meant that the pipes that provides the flow and return go past all the radiators so you have to T off at some point, just wondering how close.

I understand that the combi might have an auto bypass, but haven't chosen the boiler yet so keeping my options open, and getting some background knowledge as well.

Handy Jon - depends on the system to be honest, how many rads etc etc - your main flow and returns from the boiler will most likely be 22mm teeing of in 15mm for your rads - i always aim to have a maximum of 3 rads being fed by 15mm - if i understand you correctly, where you tee of is no relevance on a combi - like i say you just to need to ensure that your pipe sizing is correct

Thanks for the info. I thought it was ok, but just wanted to make sure. I'd seen the diagrams for layouts, but sometimes they're a bit too simplistic.

The house is only a small 2bed so going for a manifold is not worth it compared to the extra length of pipe if I had to T close to the rad.

Useful info about the 3rads on 15mm, knowing that I can make the design a bit simpler and have two of the rads on one 15mm.

Cheers.