joe90 Posted October 13, 2016 Share Posted October 13, 2016 Dear all, I have had my UFH designed and priced by Wunda ( recommended) but it did not include the feed from the ASHP/ buffer tank which is some 9 meters away. They have told me it needs to be in 22mm plastic or coppper. The floor is 100mm concrete ( with the pipes in strapped to steel mesh) on top of 300mm EPS, I would like to run the feeds within the EPS but should it be within a conduit or two conduits for separation ( heat transfer hot to cold) does not happen. Any tips greatfully received. Link to comment Share on other sites More sharing options...
CC45 Posted October 13, 2016 Share Posted October 13, 2016 We are in the same position. Lot of pipework around the manifold and location of the tank so our plumber suggested going in upstairs floor void. Will probably need a vent to prevent airlock I guess. Cc Link to comment Share on other sites More sharing options...
joe90 Posted October 13, 2016 Author Share Posted October 13, 2016 2 hours ago, CC45 said: We are in the same position. Lot of pipework around the manifold and location of the tank so our plumber suggested going in upstairs floor void. Will probably need a vent to prevent airlock I guess. Cc This will add 5 meters of pipe for both flow and return and not be in such good insulation , is this a problem? Link to comment Share on other sites More sharing options...
dogman Posted October 13, 2016 Share Posted October 13, 2016 We need to do this as well. Was looking at the pre-insulated pipe to feed the manifold. http://www.buffertanks.co.uk/shop/microflex-pre-insulated-underground-heating-pex-pipe-32mm-duo Need to check its okay in the slab and concrete Link to comment Share on other sites More sharing options...
PeterW Posted October 13, 2016 Share Posted October 13, 2016 2 minutes ago, dogman said: We need to do this as well. Was looking at the pre-insulated pipe to feed the manifold. http://www.buffertanks.co.uk/shop/microflex-pre-insulated-underground-heating-pex-pipe-32mm-duo Need to check its okay in the slab and concrete Expensive way to do it Run it between layer 1 and 2 of the EPS and it will have around 100mm of insulation - just remember to work out how to bring it through the wall properly insulated ..! Nitrile Rubber (Armaflex or InsulTube) conforms better than polyethylene insulation and then just need a cover plate to stop the beasties chewing it. Link to comment Share on other sites More sharing options...
joe90 Posted October 13, 2016 Author Share Posted October 13, 2016 Thanks, looks good but not a lot of separation between feed and return! Link to comment Share on other sites More sharing options...
dogman Posted October 13, 2016 Share Posted October 13, 2016 Could you use Kooltherm or armaflex in the slab on the flow and return or will concrete attack the insulation Link to comment Share on other sites More sharing options...
PeterW Posted October 13, 2016 Share Posted October 13, 2016 Armaflex will squash as its nitrile rubber and soft - poly would be fine but you will end up with 22x19 or something similar which is 60mm thick so you will only have 40mm of concrete and that will cause a weak point and it will crack ..! Better off below the slab in the insulation if it was me Link to comment Share on other sites More sharing options...
jack Posted October 13, 2016 Share Posted October 13, 2016 We did this. Our ASHP is on the north wall of our attached garage, which is on 300mm insulation (no idea why - easier to work to the same level across the site I guess). I made two trenches in the middle layer (of three) by cutting some EPS pieces. I then foamed in some 60mm (from memory) polypropylene pipe. The next layer of EPS held it all in place. We then got some 28mm (I think) pushfit barrier pipe and some long rolls of stick-on 3 or 4mm thick nitrile insulation tape. This was just wide enough that two parallel runs covered the outside of the barrier pipe. I greased it up with a little washing detergent and it pulled straight through the duct. There seems to be very little temp drop over the 8 or 9 metres the pipe travels to the plant room, even when running at 55 deg C. The temperature at the top of the UVC gets to exactly 55 deg C every morning throughout winter. The one thing that worried me a little was that we had to go through the ring beam. I used some foil-covered rockwool sleeves wrapped in DPC plastic to protect the pipe and insulate it from the ringbeam. Seems fine. The area where it comes through is one of the lowest stress points of the house, and the heat going through the pipes every day, at least in winter, should avoid condensation (I hope!) 1 Link to comment Share on other sites More sharing options...
CC45 Posted October 13, 2016 Share Posted October 13, 2016 8 hours ago, joe90 said: This will add 5 meters of pipe for both flow and return and not be in such good insulation , is this a problem? It will be well insulated in the upstairs floor void and will only have hot water in it when the ufh is running - so any heat loss that does happen will contribute to the space heating anyway. Boiler will be within 1m of the tank and associated pipework - it's only a longer run to the ufh manifold. Link to comment Share on other sites More sharing options...
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