andy Posted October 23, 2020 Share Posted October 23, 2020 (edited) Hi all Been a while but have had my head well and truly in the build and work, nearly at moving in point... We've finally turned on the ASHP and UFH today and am unable to get any sensible flow rate through the two Ivar mainfolds - some short loops (20m) can get up to 2l/min but that's all even with all other zones closed off. The manifolds are these: https://underfloorparts.co.uk/product/unimax-blending-10-port-underfloor-heating-manifold-with-grundfos-upm3-pump-uni-mix-temperature-contoller-mixer-valve/ I've looked at the instructions for the Ivar here: https://www.underfloorheating.co.uk/Files/127465/UFH-Mixing-kit.pdf But I'm still none the wiser and I am sure it's just something I need to sort on the primary and secondary bypass valves. I am confused why I cannot get more flow through the zones but I am sure it's just something obvious on the Ivar themselves; my loop lengths vary from 20 to 78m and I've got 2 manifolds - a 4 port and a 10 port with pressure at 2 bar. What am I doing wrong? Edited October 23, 2020 by andy Link to comment Share on other sites More sharing options...
PeterW Posted October 23, 2020 Share Posted October 23, 2020 Which pump have you got fitted ..? Is it the UPM3 Auto ..? You may need to change the flow curve as they will drop the speed right down if there is no back pressure in the system which a short loop wouldn’t provide. Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 24, 2020 Share Posted October 24, 2020 14 hours ago, PeterW said: Which pump have you got fitted ..? Is it the UPM3 Auto ..? You may need to change the flow curve as they will drop the speed right down if there is no back pressure in the system which a short loop wouldn’t provide. Don't they come set to fixed flow @ 2/3's power? Can't recall what the default is. The instruction manual to change the settings is best read when sober, lots of pictures and not much else. Try setting to constant power and see what happens, but the bottom line is, is are the returns all coming back warm? If so, then you may have no issue to resolve. Setting the primary bypass to a lower setting may help but these usually fire up out of the box. Fitted loads without ever having an issue. If the loops have not been blasted through with cold mains pressure to purge the loops of every last bit of air then that will be a huge impact on the flow rates. Has it been purged properly? Link to comment Share on other sites More sharing options...
PeterW Posted October 24, 2020 Share Posted October 24, 2020 17 minutes ago, Nickfromwales said: Don't they come set to fixed flow @ 2/3's power? Can't recall what the default is. The instruction manual to change the settings is best read when sober, lots of pictures and not much else. Can’t recall but If anyone has played with it then it will cause issues as you’d need to reset to factory to start again. Model number would be useful Link to comment Share on other sites More sharing options...
andy Posted October 27, 2020 Author Share Posted October 27, 2020 (edited) Sorry didn't see the replies guys - thanks as ever. I have 4 pumps - 1 in the loft for the Samsung ASHP, 1 in the loft for loops to UFH manifolds and 1 on each manifold as follows: Grundfos UPS3 15-50 28mm to ASHP Set to constant pressure II Flow rate is 26l/min Light I (green) on the pump Low loss header in the loft to buffer that, with UFH 22mm flows coming off that Grundfos UPS3 15-50 22mm to manifolds Set to constant pressure II Lights I (green), II and III on pump when running Splits to each manifold in the loft, 22mm continue down to each manifold Grundfos UPM3 Auto L 25-70 on each manifold 22mm Set to constant pressure 3 Lights I (green), II and III on the pum Pump a bit noisy and I wonder if it's fighting with pump in loft...? The stuff in the loft was done separately to the UFH manifolds and the plumbing company just put in their standard stuff and I suspect that I don't want or need the pump in the loft for the manifolds and the pumps could be fighting each other. The company doing the loft plumbing knew there was a pump by each manifold and I think they should not have put that one in. Flow from ASHP is hitting each manifold at 30C. They also didn't recommend a TMV on the manifolds, said they've never fitted one and see it as pointless. Problem is even with all zones closed down I can only get circa 4l/min round a circuit, with all zones open I can barely get any flow to each zone - barely a movement at the top of the flow meter. The manifold has primary and secondary bypass - I've set the primary bypass to Kv0 as the local TMV is not yet fitted (long story, it is going on soon). Secondary bypass I took screw out by cannot seem to turn the 5mm key to turn and I don't want to force it. With regards to purging, yes all air should've been purged. The return temperature from each manifold is barely warm after the system has been running all morning. Edited October 27, 2020 by andy Link to comment Share on other sites More sharing options...
Fly100 Posted October 27, 2020 Share Posted October 27, 2020 Andy, Ive had a simular issue, however I only have on mandiflod from an Oil boiler. No mater what I did i could net get the flow above 2.5l/s. Various circuits closed etc. Slow warm up times followed with short cycling. Ive fitted the Salu Auto Balancing Actuators, this has greatly helped my problem, leaving me to thing the old accutator did not open fully. It would seem even a mm of lost movement can alter the flow. I understand this a slight curve ball, but have you tried removing the actuators completely ? FLY 1 Link to comment Share on other sites More sharing options...
andy Posted October 27, 2020 Author Share Posted October 27, 2020 2 minutes ago, Fly100 said: Andy, Ive had a simular issue, however I only have on mandiflod from an Oil boiler. No mater what I did i could net get the flow above 2.5l/s. Various circuits closed etc. Slow warm up times followed with short cycling. Ive fitted the Salu Auto Balancing Actuators, this has greatly helped my problem, leaving me to thing the old accutator did not open fully. It would seem even a mm of lost movement can alter the flow. I understand this a slight curve ball, but have you tried removing the actuators completely ? FLY At this point I have no actuators on and the screw caps are fully backed off, the actuators are Loxone ones that will be going on once I've got the system balanced (or if...). Link to comment Share on other sites More sharing options...
andy Posted October 27, 2020 Author Share Posted October 27, 2020 I think at this point I should rip out the pump and mixing sets by the manifold, put one of these 25-70 pumps up in the loft instead of the 15-50 and see where that leaves me with regards to flow rates. Given my supply to manifolds is 30C I am not gaining anything by having the mixing set I would say. Thoughts? Link to comment Share on other sites More sharing options...
Simtronic Posted October 27, 2020 Share Posted October 27, 2020 The flow through each individual circuit is only dependant on the pump at each manifold, the thermostatic blending valve is a sort of an automatic bypass. I found this needs to be set to the highest temperature while bleeding the air out as I had similar problems when I first installed mine 5 years ago. I hope this helps Link to comment Share on other sites More sharing options...
ProDave Posted October 27, 2020 Share Posted October 27, 2020 5 hours ago, andy said: Problem is even with all zones closed down I can only get circa 4l/min round a circuit, with all zones open I can barely get any flow to each zone - barely a movement at the top of the flow meter. The manifold has primary and secondary bypass - I've set the primary bypass to Kv0 as the local TMV is not yet fitted (long story, it is going on soon). Secondary bypass I took screw out by cannot seem to turn the 5mm key to turn and I don't want to force it. Explain these bypasses please, if possible with a picture of your actual manifolds? Link to comment Share on other sites More sharing options...
andy Posted October 28, 2020 Author Share Posted October 28, 2020 16 hours ago, ProDave said: Explain these bypasses please, if possible with a picture of your actual manifolds? Here you go, primary highlighted in yellow, secondary in green on zoomed in image: Link to comment Share on other sites More sharing options...
ProDave Posted October 28, 2020 Share Posted October 28, 2020 What's that actuator head position on the left of the blending valve? Surely with a blanking plug screwed on, that will be shut? Link to comment Share on other sites More sharing options...
andy Posted October 28, 2020 Author Share Posted October 28, 2020 1 hour ago, ProDave said: What's that actuator head position on the left of the blending valve? Surely with a blanking plug screwed on, that will be shut? It’s fully unscrewed. I wonder if it’s something to do with the pump in the loft and at manifolds interfering with each other but tbh I don’t get it at this point... Link to comment Share on other sites More sharing options...
dpmiller Posted October 29, 2020 Share Posted October 29, 2020 are the flow and return the right way round at the manifold? Link to comment Share on other sites More sharing options...
andy Posted October 29, 2020 Author Share Posted October 29, 2020 Yes, flow to the top by the flow meters. I am going to get it replumbed directly avoiding the mixing set to see if the flow goes up, if it doesn't then I am really not sure what to do... Link to comment Share on other sites More sharing options...
ProDave Posted October 29, 2020 Share Posted October 29, 2020 Try turning off ALL the other pumps, so you only have the manifold circulating pump running and see if that makes a difference (thinking if flow and return TO the manifold is piped backwards, or a pump is connected backwards, it will be fighting the manifold pump) Link to comment Share on other sites More sharing options...
dpmiller Posted October 29, 2020 Share Posted October 29, 2020 ^ as Dave mentioned, I'd be looking at the "supply" flow and return direction. Link to comment Share on other sites More sharing options...
andy Posted October 29, 2020 Author Share Posted October 29, 2020 Plumber here tomorrow morning, so will have a look at what the hell's going on here... Link to comment Share on other sites More sharing options...
andy Posted October 30, 2020 Author Share Posted October 30, 2020 Problem was an un-noticed 1/4 turn valve that we'd all overlooked on top left... once it was opened, all fine. Grrrrrr.... Link to comment Share on other sites More sharing options...
andy Posted October 31, 2020 Author Share Posted October 31, 2020 22 hours ago, andy said: Problem was an un-noticed 1/4 turn valve that we'd all overlooked on top left... once it was opened, all fine. Grrrrrr.... And in case anyone else is caught out by this, the isolation valve wasn't visible once the unit had been installed and wasn't checked it was open prior to mounting. It's as per the pic below, flows are now absolutely normal. 1 Link to comment Share on other sites More sharing options...
PeterW Posted October 31, 2020 Share Posted October 31, 2020 Nice to hear it’s sorted. I know @Nickfromwales likes those Ivar manifolds but you’ve just given me yet another reason not to like them ...!! Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 31, 2020 Share Posted October 31, 2020 20 minutes ago, PeterW said: Nice to hear it’s sorted. I know @Nickfromwales likes those Ivar manifolds but you’ve just given me yet another reason not to like them ...!! Really? If an installer doesn’t check all in line flow valves are open then that’s now the fault of a bit of kit is it? No, it’s not. ?? Not checking pump / gate valves are open is 1st year apprentice error. I’ve not had one yet which has caused any issues. 1 Link to comment Share on other sites More sharing options...
PeterW Posted October 31, 2020 Share Posted October 31, 2020 It’s the weird bypass valve bit I don’t like / get as that is another set of issues all built into a single unit. What’s the manufactures warranty on those manifolds ..? Link to comment Share on other sites More sharing options...
andy Posted October 31, 2020 Author Share Posted October 31, 2020 1 hour ago, Nickfromwales said: Really? If an installer doesn’t check all in line flow valves are open then that’s now the fault of a bit of kit is it? No, it’s not. ?? Not checking pump / gate valves are open is 1st year apprentice error. I’ve not had one yet which has caused any issues. Exactly. Link to comment Share on other sites More sharing options...
Russell griffiths Posted October 31, 2020 Share Posted October 31, 2020 2 hours ago, PeterW said: Nice to hear it’s sorted. I know @Nickfromwales likes those Ivar manifolds but you’ve just given me yet another reason not to like them ...!! Really it’s a bloody great valve turned by a flat head screwdriver, I spotted it instantly when I installed mine. Link to comment Share on other sites More sharing options...
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