two pipe central heating loop layout.

simon_t · 16 Oct 2006

Hello,

I have laid out a central heating two pipe system in my two bed flat. The 22mm pipe comes out from the boiler around the flat and back to the return connection. From this loop I have tee'd off for each radiator in turn, connecting to flow and retrun.

All seems fine, but my question is should the loop pass through a rad at the end as this image shows below? (image is not my exact layout - but taken from the internet.)

Mine forms a complete loop, so that even if all the rads are shut the water can still flow. If so it is not difficult for me to break the loop if needed, but I'd rather not bother if it will make little difference. I wasn't sure if this would effect the flow patterns around the system.

Any help would be appreciated.

Simon

Steve__M · 16 Oct 2006

The loop looks pretty standard, not sure what you are considering as an alternative.

A 22mm pipe seems large for 2 radiators. Unless the furthest radiators on the loop are very large (more than 2kW) advice is that the water flow rate will be too slow allowing potential build up of sludge in the pipes.

simon_t · 16 Oct 2006

My layout is basically the same, only that the loops on the image above each use a radiator to complete the loop, mine does not. The flow and return form a complete loop on there own, independent of the radiators.

Hope that makes some sense...

Steve__M · 16 Oct 2006

If you connect the flow and return together, without a radiator in between, then the water will go straight along the main pipe and won't bother going through the radiators!

doitall · 16 Oct 2006

Does the flow and return go into the same pipe e.g. a one pipe system

simon_t · 17 Oct 2006

No each rad takes its' hot water from the flow and then dumps it back into the return pipe, so that the hot water is never cooled as it flows onto the next rad.

Steve, if I cut the flow/return loop so that it has to flow through the last radiator on the system (as the flow becomes the return) this will increase the flow through all the other rads?

Steve__M · 17 Oct 2006

simon_t said:
Steve, if I cut the flow/return loop so that it has to flow through the last radiator on the system (as the flow becomes the return) this will increase the flow through all the other rads?

Simple answer is yes.

All things being equal, there would actually be more flow in the first radiator rather than the last.

You then have to balance the system to get the right amount of water going to each radiator. There are references as to how to do this on these forums.

simon_t · 17 Oct 2006

I knew it would be a good idea to leave the floorboards loose!

I'll give it a try tonight and see how much of a difference makes before balancing.

simon

Steve__M · 17 Oct 2006

In that case, I hope I correctly understood your layout and haven't misled you.

simon_t · 18 Oct 2006

Didn't get around to doing it last night, but even if it doesn't work then it's not a problem to put it back to its' original operation as it just a case of splitting the flow \ return so that it flows around the system and re-connecting it if turns out to be worse.

Thanks for the advice so far.

Simon

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two pipe central heating loop layout.

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