Mon, 25 May 2026 06:27:40 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307361#Comment_307361 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307361#Comment_307361 Sat, 30 Nov 2024 11:18:38 +0000 Victorianeco
Are Trunk and feed layouts now outdated? Should I be best running everything back to a central manifold? It would mean more pipework but potentially less joints.

Does this then make it easier for balancing etc?

If we do that, can all of the radiators be fed from 10mm potentially? Where can I get some kind of calculation or diagram made? The traditional S plan would be easy to do in 22mm and 15 to the radiators. Probably a separate circuit for upstairs and one for downstairs

Any thoughts please?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307362#Comment_307362 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307362#Comment_307362 Sat, 30 Nov 2024 12:32:40 +0000 Artiglio Using plastic pipe there are no joints under the floor other than to the manifold and copper tails, doddle running the pipes and any holes in joists are only 12mm. But these are heated with gas combi boilers, all work fine with 60 degree flow temps but invariably i’ll find tenants have it much higher. The flats in the block built in 2004 will quite happily run at 50 degrees, but it’s a waste of breath telling tenants that, 60 degrees seems to be a temperature at which people see rads as being sufficiently hot.
Only problems i’ve had is when i’d neglected to top up inhibitor in 2 flats and flakes of scale had collected in the manifold and blocked a pipe run. But that was simple if time consuming to sort out and won’t happen again.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307364#Comment_307364 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307364#Comment_307364 Sat, 30 Nov 2024 15:56:46 +0000 Victorianeco
This radiator has a heat output of 3kW at delta 50C]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307365#Comment_307365 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307365#Comment_307365 Sat, 30 Nov 2024 19:16:12 +0000 Victorianeco
I have read it needs to be a certain size to ensure deposits aren't left or excess wear on the pipe. The is also the sound.

If anyone knows how to calculate this effectively given pipe runs and temperature I'd be most grateful for my own learning curve?

If I can run everything in 10mm drops or runs without issue it will make the plumbing and chases a lot easier]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307366#Comment_307366 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307366#Comment_307366 Sat, 30 Nov 2024 19:21:30 +0000 revor https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307367#Comment_307367 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307367#Comment_307367 Sat, 30 Nov 2024 20:05:55 +0000 Victorianeco
I was thinking a simple manifold, don't need flow rates really do I? I could use the danfoss ras-b trv that have self balancing valves.

My query is more to do with will 10 or 15 work without creating noise or issues?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307368#Comment_307368 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307368#Comment_307368 Sat, 30 Nov 2024 20:58:23 +0000 philedge
Remember that anyone specifying flow temps for you isn't going to be paying your bills!]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307369#Comment_307369 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307369#Comment_307369 Sat, 30 Nov 2024 21:09:38 +0000 Victorianeco https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307373#Comment_307373 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307373#Comment_307373 Sun, 01 Dec 2024 11:13:21 +0000 revor Posted By: VictorianecoMy query is more to do with will 10 or 15 work without creating noise or issues?

To determine if you will have noise you need to know the flow rates. There are tables of pipe dia, flow rates, heat carried with limits where you can expect noise. At moment cannot lay my hand on my heating guide but that is to do with conventional boilers but some of the info would be transferable I guess. A friend recently had her heating upgraded with 2 heat pumps. They ran a pipe through her kitchen fixed to the wall within ducting and she is complaining that bit is noisy. So you are wise to look into this aspect.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307375#Comment_307375 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307375#Comment_307375 Sun, 01 Dec 2024 13:08:34 +0000 djh Posted By: Victorianecowe're also not interested in achieving 21c in every room when it is -2c outsideBear in mind that you might want to do that when you're ill and older! i.e. requirements change depending on circumstances. But you don't have to meet extremes using the normal heating system. You can always add additional heaters if necessary.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307376#Comment_307376 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307376#Comment_307376 Sun, 01 Dec 2024 13:13:38 +0000 Victorianeco
Or dare I say it, an extra jumper or thermals ?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307378#Comment_307378 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307378#Comment_307378 Tue, 03 Dec 2024 11:29:29 +0000 Victorianeco
I can' really find decent suppliers of 16mm pipe that would include 90deg fittings such as hep20 brand

Should I just go with Hep20 as they have a wide range of fittings readily available? I'd rather not have any 16mm compression fittings hidden in floor boards or walls (Can anyone recommend a 16mm push fit supplier/brand?)]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307380#Comment_307380 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307380#Comment_307380 Tue, 03 Dec 2024 16:40:44 +0000 djh Posted By: VictorianecoI have the heat loss or heat output per radiator and I know the Delta t for each rad (5c ideal). Does anyone know how I can then calculate the speed or flow in the pipe either at 10mm or 15mm?The energy carried away is flow rate (l/s) * specific heat capacity of the transfer medium (water or glycol as appropriate) * deltaT at the heat pump (normally designed for 5).

So flow-rate (l/s) = heat-output / (4200 * 5)

To convert the flow rate to speed, divide it by the internal cross-sectional area of the pipe. i.e pi * r² Note that r is in cm, not mm, and the speed is in cm/sec. More simple sums if you want different units.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307381#Comment_307381 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307381#Comment_307381 Tue, 03 Dec 2024 18:26:41 +0000 Victorianeco https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307382#Comment_307382 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307382#Comment_307382 Tue, 03 Dec 2024 18:42:02 +0000 tony https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307383#Comment_307383 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307383#Comment_307383 Tue, 03 Dec 2024 20:13:47 +0000 Victorianeco
If I were to use traditional trunk and branch style the longest length would be about 8lm]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307384#Comment_307384 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307384#Comment_307384 Wed, 04 Dec 2024 07:35:11 +0000 Peter_in_Hungary Posted By: VictorianecoThe largest length of pipe from manifold to radiator would be ~12lm

If I were to use traditional trunk and branch style the longest length would be about 8lm
Don't forget that fittings (Tees etc.) add resistance which can be calculated as equivalent pipe length (tables on the internet) so your 8 lm would increase accordingly but the manifold would also add equivalent pipe length so it's not as simple as it would first seem, unless you have already accounted for fittings in the 12 lm and 8 lm.

Oh and I've not seen any plumbers accounting for flow rates and fittings resistance when installing domestic CH. they just put in a (oversized) pump and screw down the lockshield valves as needed.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307385#Comment_307385 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307385#Comment_307385 Wed, 04 Dec 2024 08:40:28 +0000 revor Posted By: VictorianecoI can' really find decent suppliers of 16mm pipe that would include 90deg fittings such as hep20 brand

16 mm is a continental size widely used here now my u/f pipe is 16mm profitherm which you can use in your application. It bends easily so it minimises fittings and retains shape, you need compression fittings of that size though.

Don't think you will find this in the general plumbers merchants if your MCS installer has recommended 16mm ask him/her where they source it from.

There is also another system available seemingly becoming popular which is Alpex needs a special compression tools to make the joints. This can also be bent and retain shape system is popular because it avoids hot work on building site sometimes a H&S fire prevention requirement. See link explore rest of site also.

https://www.underfloorheating.co.uk/product-category/plumbing/pipe/plumbing-and-heating-pipe/]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307388#Comment_307388 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307388#Comment_307388 Wed, 04 Dec 2024 14:57:58 +0000 Peter_in_Hungary Posted By: revorThere is also another system available seemingly becoming popular which is Alpex needs a special compression tools to make the joints.
Alpex is the de facto standard here for any pipe work that is not on show. It can be had plain or pre-insulated (red or blue). Whilst a tool is needed for the joints it is quicker than soldering up copper. Very easy to use.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307396#Comment_307396 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18246&Focus=307396#Comment_307396 Wed, 04 Dec 2024 18:16:54 +0000 Victorianeco