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[Closed] Underfloor heating advice

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Hi all,

Have been busy building a second hand conservatory and am now up to sorting the flooring out. I have built up so all I have left to do is 100mm celotex and then 75mm screed.
At this point I want to install underfloor heating pipes, The floor is 26.8m2 by my reckoning of 150mm centres I need 200m of pipe. I have read a couple of articles which say I cannot have pipe runs greater than 100m so would need to do 2 runs. Is this the case, how do I finish the ends into the garage in/in/out/out or in/out/in/out on water. what would the spacing be next to the manifold. I cannot afford manifold etc. at the moment but cannot see the point in not fitting the pipes at this stage.

All advice welcome.

Thanks

Marcel


 
Posted : 11/11/2013 8:07 pm
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Oh and is 16mm x 2 standard underfloor heating pipe.


 
Posted : 11/11/2013 8:10 pm
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Definitely need two runs there. 100m is the longest run, better off sticking to 75m if possible, but 100 should be fine. Is the manifold going to be close to the conservatory, because if not that distance needs factoring into the pipe length? Bring all the pipes out close to each other, the distance between the outlets abd inlets on the manifold is only a couple of inches. I would bring them in out, in out.

16mm is the standard for domestic use. Don't forget to put a wire in for the thermostat before plastering. And the screed must have fibers mixed into it to stop it cracking

Good luck, if you need any more help just ask, I have fitted a fair few now. And enjoy toasty warm feet!


 
Posted : 11/11/2013 8:21 pm
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Excellent, thanks for that, manifold will be other side of conservatory wall in garage. In/out in/out sounds ideal for the layout I have in mind for the two runs.

I dont need a thermostat in the screed do I.?


 
Posted : 11/11/2013 8:28 pm
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We have never put a floor thermometer in the screed, it is possible, and might make it more efficient but works fine without.

No extra pipe runs to the manifold is always good. Sounds like you've got it sorted!

Tom


 
Posted : 11/11/2013 8:32 pm
 Bear
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pipe centres at 100mm too if you can.


 
Posted : 11/11/2013 9:17 pm
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Hope laying out the pipes on the insulation goes better for you than it did for me. I came very close to dumping the whole lot in a skip! Worth the effort as I now wish I could put it in the whole house but I was not good company at the time.


 
Posted : 11/11/2013 9:25 pm
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Not all pipe is 16mm, some manufacturers use 15mm and some 17mm, there's also an Osma one that is 12mm but it's designed for shallow floors. You can go direct to some manufacturers and they'll design the full system for you but for a conservatory it's a bit overkill.

Best solution would be a John Guest underfloor pack, they do a 30sq/m one which comes with pump, manifold, controls, pipe, clips etc and you can get it with a wireless stat if that floats your boat.


 
Posted : 11/11/2013 9:36 pm
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Thanks for all of the replies, are you sure on 100mm centres as all ive read so far are for 150mm centres. Have looked at the underfloor heating packs but finances are so tight I can only do the pipes at the mo.
Trying to make it futureproof whilst I can.


 
Posted : 11/11/2013 9:43 pm
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Would this be a good pipe to use

http://www.theunderfloorsuperstore.co.uk/pert-al-pert-multilayer-underfloor-heating-barrier-pipe-16x2mm---200m-coil-158-p.asp

Thanks again in advance


 
Posted : 11/11/2013 9:46 pm
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My centres are at 300 ie one loop in 600; works absolutely fine.


 
Posted : 11/11/2013 9:48 pm
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Buy two 100m coils of John Guest Speedfit barrier pipe and some clips then lay your loops out, when the time comes buy the pack and eBay the clips and pipe. If you go for the Emmeti stuff you'll spend more in the long run from what I can see.

I work in a plumbers merchant and 99% of the people I deal with on a daily basis would go for the speedfit pack as it's a trusted name and a known quantity. I've only spoken to one chap who had to deal with Emmeti to get a replacement actuator and it took him 3 weeks to get it.


 
Posted : 11/11/2013 9:59 pm