Central heating design-flow/return

[lonspwi]

In terms of efficiency, is it best to run flow and return in a loop ending at the last radiator or will it compromise the heat transfer capability if another flow and return is Tee'd off.
I have a remote radiator and it would be easier if I just took a Tee off the main flow/return.

Thanks in advance

 

[Slugbabydotcom]

In terms of cost efficiency it is better for you to call a heating engineer round or at least get a book out of the library so that we at least have a clue of the type of set up you have before we can be of any help to you.

It sounds as though you are proposing to add a radiator somewhere.

Flow and return in a loop ending at the last radiator

sounds vaguely like you are proposing a one pipe system which is not the done thing these days.

Apart from that it is hard to make sense of what your current system and future aims are.

I summon the great and wonderous Kevplumb and one of his amazing crystal balls to help you

 

[kevplumb]

you called oh great one

 

[Slugbabydotcom]

Look into the ball , through the fog and tell me what you see

 

[lonspwi]

Sorry Slug, re-reading my initial post does sound vague. It was a general question on design and not to solve a problem.
I'll try and make it sound clearer.
Ok, I have 2 pipes entering the first floor level, flow pipe coming from zone valve, return going back to boiler. In the normal scheme of things, the flow and return would run in a parallel fashion, providing the flow and return to each radiator up to the last rad.
Now, say I had a long hallway with 3 radiators in a nice line and then I had a radiator at an extreme corner, away from the group of rads I want to feed, would it be better to run the flow and return pipes to the extreme rad and then double back the flow and return to feed the remaining rads, or is it acceptable to put a tee on the flow and a tee on the return just to feed this one extreme rad ?

 

[Slugbabydotcom]

Still a little vague but I'll make some assumptions

You are proposing a two pipe system
The radiator sizes are not excessive
The pipe runs are not excessive
The pipes are correctly sized [I would expect 15mm to cope for four rads under most circumstances]
You have one rad 'out on a limb'

Now to answer the question...... Run the pipe by the shortest route so that you use the least amount of pipe.So long as each rad gets an adequate flow and return it doesnt matter.

It not only costs less to install but from the surface of the pipe you will be losing x number of watts per metre of heat, in places that you dont want to lose that heat; for all extra pipe that you fit and dont need

 

[lonspwi]

Yes, it is a 2 pipe system using 22mm plastic pipe, the rad sizes nor are the pipe runs excessive. Yes, I have one rad 'out on a limb'

So it looks like you have answered my question - use the least amount of pipe possible.

Thanks for you replies.

 

[Slugbabydotcom]

Good chance that you wont need 22mm pipe anywhere past the first radiator so just run it all in 15 after that.

Pipe sizing is an art in itself and its not something that a lot of plumbers do a lot of either because once you have experience you know if it will work or not for most cases. I wouldnt go digging the books out to save a few quid on piping on a job this size.

Sure most will agree that my advice is cautious and your system will work if you follow the above