jfb Posted June 28, 2019 Share Posted June 28, 2019 I am getting set to pour my concrete slab with A142 mesh and UFH pipes attached and have a couple of questions. I bought a Hetta 4 way manifold kit with 2 x 200m 16mm pert-al-pert pipe second hand (unused) on Gumtree a while back so hopefully it works and has all the relevant bits! 1. I notice that the kit doesn't include any 90 degree conduit for near the manifold - should i get some like this? https://www.toolstation.com/jg-speedfit-conduit-elbow/p74951?utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&gclid=EAIaIQobChMIx_qppoKM4wIV4b3tCh3k_QOcEAQYASABEgKTl_D_BwE 2. i have a couple of expansion joints where the pipe will go through - should I use conduit for those sections as well? 3. I was not planning on pressure testing before the pour (mostly because plumbing isn't my strength, don't have a compressor, having looked at some advice on here suggesting it isn't absolutely necessary, also will be running at low temperature (100mm spacing) so pipe expansion issues not so relevant) - do I have to fit the pipe to the manifold before the pour? I was thinking I could leave the pipes sticking up in line and fit manifold later. I think I need someone to tell me to stop being stupid/lazy and just fit it now as I can see it can't be as easy to fit later - it is just that the wall isn't quite ready to fix to yet. 4. Can I use a vibrating poker when I am pouring the concrete or could that damage the pipe? 5. It is an open plan space of 25m2 - at 100mm spacing I make that 10m per m2 so 250m pipe in total is needed. It will all be run as one zone. I am planning to use 2 loops of 125m each in a spiral pattern. Is there any reason why I should do 4 shorter loops instead? 1 Link to comment Share on other sites More sharing options...
BotusBuild Posted June 28, 2019 Share Posted June 28, 2019 2 hours ago, jfb said: I am getting set to pour my concrete slab with A142 mesh and UFH pipes attached and have a couple of questions. I bought a Hetta 4 way manifold kit with 2 x 200m 16mm pert-al-pert pipe second hand (unused) on Gumtree a while back so hopefully it works and has all the relevant bits! 1. I notice that the kit doesn't include any 90 degree conduit for near the manifold - should i get some like this? https://www.toolstation.com/jg-speedfit-conduit-elbow/p74951?utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&gclid=EAIaIQobChMIx_qppoKM4wIV4b3tCh3k_QOcEAQYASABEgKTl_D_BwE Q: Why do you think you that conduit? Is space tight? You think it will look neater? My experience is that the actual UFH pipe is reasonably flexible and if where it comes out of the floor and is connected to the manifold (direct connections are highly recommended) it is hidden away or boxed in then the "look" is not so important. 2 hours ago, jfb said: 2. i have a couple of expansion joints where the pipe will go through - should I use conduit for those sections as well? Q: To protect the UFH pipe? I would recommend having different loops of UFH in different section of solid floor 2 hours ago, jfb said: 3. I was not planning on pressure testing before the pour (mostly because plumbing isn't my strength, don't have a compressor, having looked at some advice on here suggesting it isn't absolutely necessary, also will be running at low temperature (100mm spacing) so pipe expansion issues not so relevant) - do I have to fit the pipe to the manifold before the pour? I was thinking I could leave the pipes sticking up in line and fit manifold later. I think I need someone to tell me to stop being stupid/lazy and just fit it now as I can see it can't be as easy to fit later - it is just that the wall isn't quite ready to fix to yet. I strongly recommend pressure testing the pipes before you pour. If there is a problem once the concrete is set off, then you are in a whole load of misery to find and fix the leak. Connect the loops to the manifold, open all the valves, fill with water and leave for an hour or two. Fix any leaks, try again. Rinse and repeat (pun intended) 2 hours ago, jfb said: 4. Can I use a vibrating poker when I am pouring the concrete or could that damage the pipe? Yes. Just be careful 2 hours ago, jfb said: 5. It is an open plan space of 25m2 - at 100mm spacing I make that 10m per m2 so 250m pipe in total is needed. It will all be run as one zone. I am planning to use 2 loops of 125m each in a spiral pattern. Is there any reason why I should do 4 shorter loops instead? See answer regarding expansion joints. 2 hours ago, jfb said: 1 Link to comment Share on other sites More sharing options...
jfb Posted June 28, 2019 Author Share Posted June 28, 2019 thanks botus - a lot of help. i will try and get my plumbing head on! 29 minutes ago, BotusBuild said: strongly recommend pressure testing the pipes before you pour. If there is a problem once the concrete is set off, then you are in a whole load of misery to find and fix the leak. Connect the loops to the manifold, open all the valves, fill with water and leave for an hour or two. Fix any leaks, try again. Rinse and repeat i have heard you are meant to pressure test first to 2 bar first and then 10 bar. depending on local supply would 2 bar be typical water pressure? and for more you would need a compressor? Link to comment Share on other sites More sharing options...
ProDave Posted June 28, 2019 Share Posted June 28, 2019 I am not even sure that bend is meant for UFH pipe. It looks like a bend for electrical conduit to me? Link to comment Share on other sites More sharing options...
Temp Posted June 28, 2019 Share Posted June 28, 2019 90 degree bend "supports were provided with my UFH pipe. I gather it's to stop the pipe suddenly kinking when you try to achieve the sharp rad bend below a manifold. Here are similar supports on ebay but I haven't checked the diameter.. https://www.ebay.co.uk/itm/Underfloor-Heating-Pipe-Bend-Supports-Cold-Forming-pr-14-18mm-Pipes-/264303295351 Link to comment Share on other sites More sharing options...
Temp Posted June 28, 2019 Share Posted June 28, 2019 I would strongly recommend a pressure test. Looks like HSS can rent you the pump but you may need to get adaptors. Many UFH systems have connections to suit a hose. https://www.hss.com/hire/p/pipe-pressure-tester There are bound to be vids on youtube. Link to comment Share on other sites More sharing options...
BotusBuild Posted June 28, 2019 Share Posted June 28, 2019 41 minutes ago, jfb said: i have heard you are meant to pressure test first to 2 bar first and then 10 bar. depending on local supply would 2 bar be typical water pressure? and for more you would need a compressor? Statutory mains pressure should be around 1 Bar (enough to raise water to a height of 10m). "As a guide, if you have a suitable single service pipe, the first tap in the home (this is usually the kitchen tap) should be able to fill a 4.5 litre (one gallon) bucket in 30 seconds, with all other taps and appliances turned off." - from Watersage.org.uk Mains pressure in a closed system will reveal leaks. For higher pressure, yes, either a compressor or I have seen an adapter created by a plumber that allowed an air pressure test with a car foot pump. Note: another recommendation is to fill the pipes with water before you pour the concrete to stop them being compressed by the concrete. Link to comment Share on other sites More sharing options...
Simplysimon Posted June 28, 2019 Share Posted June 28, 2019 out of curiosity, can you walk on the pipes whilst concreting? i'm clipping into trays not to the insulation Link to comment Share on other sites More sharing options...
jfb Posted June 28, 2019 Author Share Posted June 28, 2019 Yes it's pretty resilient. Link to comment Share on other sites More sharing options...
PeterW Posted June 28, 2019 Share Posted June 28, 2019 One of the other reasons to fill it with water and cap off is it makes it much harder to crush. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now