Andrew Posted July 12, 2020 Share Posted July 12, 2020 4 hours ago, Nickfromwales said: Yup. The valve is actuated by the TRV style head and that gets its reference via a capillary wire that is connected to a thermo-probe ( which is inserted into a pocket to detect the flow temp after the pump, eg after return water has been blended back in already ) and the TRV head will only open if the flow temp is less than the setting on the TRV head. The valve is normally fully open, so it promotes great full flow rates when the UFH starts up and asks for heat, and only starts to close as the temp set at the probe meets the temp set on the head. Thanks, that’s good as I have the Wunda pump set (as yet uninstalled) which has a mixer with a lowest temperature setting of 30 degrees but plan to run the ASHP a bit less than that when in UFH mode. I like the idea of keeping the mixer as a protection for overheating the floor just in case something goes wrong. 4 hours ago, Nickfromwales said: There is no 'cold' to speak of, just the available return water and whatever temp that is. Of course, wasn’t thinking. 1 Link to comment Share on other sites More sharing options...
redtop Posted July 12, 2020 Share Posted July 12, 2020 On 11/07/2020 at 19:04, Nickfromwales said: Blending valve ALWAYS. You will need a low temp tolerable one such as the Ivar as normal TMV’s very much dislike low flow temps ( 30oC and below ) but these cope very well. these come with the Grundfos pumps but I have seen the wilo ones seem to be preferred? Link to comment Share on other sites More sharing options...
Nickfromwales Posted July 12, 2020 Share Posted July 12, 2020 20 minutes ago, redtop said: these come with the Grundfos pumps but I have seen the wilo ones seem to be preferred? Yes, some find the Grundfos noisy but I think they must not be turning them down to the lower setting. They get delivered set to run at max IIRC for purging / commissioning so need to be set up properly for the particular duty. Link to comment Share on other sites More sharing options...
Pocster Posted July 13, 2020 Share Posted July 13, 2020 My installer doesn’t think a blending valve is needed for ufh ASHP . I’ve sent him some of the comments from here - be interesting to hear his view. Link to comment Share on other sites More sharing options...
Nickfromwales Posted July 13, 2020 Share Posted July 13, 2020 Just now, pocster said: My installer doesn’t think a blending valve is needed for ufh ASHP . I’ve sent him some of the comments from here - be interesting to hear his view. Get a new installer. 1 1 Link to comment Share on other sites More sharing options...
Pocster Posted July 13, 2020 Share Posted July 13, 2020 6 minutes ago, Nickfromwales said: Get a new installer. To late . They’re doing everything I.e pv , uvc , ASHP So I’m obliged to the contract . Pv in . Global pandemic put a hold on things . So only just back in comms with them . Link to comment Share on other sites More sharing options...
Pocster Posted July 13, 2020 Share Posted July 13, 2020 14 minutes ago, Nickfromwales said: Get a new installer. Lol @Nickfromwales you’ll like this . My guy hasn’t replied yet . So for fun I just called 2 random online ufh / ASHP retailers whom have a technical support team . Both said blender not needed and they don’t sell a blender with their ashp systems . Their logic being the ASHP never generates water hot enough to be an issue . Now don’t shoot the messenger !! ? Link to comment Share on other sites More sharing options...
Nickfromwales Posted July 13, 2020 Share Posted July 13, 2020 1 minute ago, pocster said: Their logic being the ASHP never generates water hot enough to be an issue . Most are capable of a minimum of 55oC ?!? Link to comment Share on other sites More sharing options...
Nickfromwales Posted July 13, 2020 Share Posted July 13, 2020 2 minutes ago, pocster said: they don’t sell a blender with their ashp systems It would come with the UFH manifold not the ASHP Link to comment Share on other sites More sharing options...
PeterW Posted July 13, 2020 Share Posted July 13, 2020 15 minutes ago, pocster said: Their logic being the ASHP never generates water hot enough to be an issue . Ask them to guarantee the output of the ASHP, and warranty against any floor damage in the event that the ASHP overheats the floor. And then fit a blending valve.... 2 Link to comment Share on other sites More sharing options...
Pocster Posted July 13, 2020 Share Posted July 13, 2020 10 minutes ago, PeterW said: Ask them to guarantee the output of the ASHP, and warranty against any floor damage in the event that the ASHP overheats the floor. And then fit a blending valve.... This is exactly what I was thinking . Link to comment Share on other sites More sharing options...
joe90 Posted July 13, 2020 Share Posted July 13, 2020 A bit late to this thread, but I have a Wunda manifold and ditto, despite asking fir a blending valve they did not send one as I said I had an ASHP so had to insist they send one. My ASHP delivers 48’ water whatever the use ( bloody controller impossible to fathom, even Jeremy had trouble). DHW direct to coil in DHW tank and heating to buffer tank (am having second thoughts about it’s being required?) then blending valve on manifold down to 24’. The buffer tank (I suppose) gives me instant hot water to the manifold so saves the ASHP getting up to temp. In the heating season the buffer is permanently topped up and room stat calls for heat from that tank. Link to comment Share on other sites More sharing options...
Pocster Posted July 13, 2020 Share Posted July 13, 2020 Digest fellas !! The HP pump isn’t circulating through the UFH, it’s only circulating to the buffer. There are pumps on each of the UFH manifolds that draw the heat from the buffer when one of their respective zones call. The actuators will close and the pump stop circulating once the rooms are satisfied so I’m not sure what constant circulating or overheating they are talking about. The flow temperature from the heat pump is weather compensated at a maximum flow temperature of 35C at -1.6C external temp. down to 20C at 15C external temp. The mixers are mechanical so there is no control, they are set manually. The minimum temperature they can be set to (35C) is higher than the maximum design temperature of your system so they are practically redundant as under the design conditions the heat pump will not produce heat higher than this. If you want to add mixers you will need to add an additional pump and control on the buffer side to take the heat from the buffer to the manifolds when either of them called. Also, as the mixer wont completely close the flow temperature will need to be set higher to compensate for this mixing and increase the running costs. I do not recommend mixers on a low temperature system. Link to comment Share on other sites More sharing options...
PeterW Posted July 13, 2020 Share Posted July 13, 2020 4 minutes ago, pocster said: The HP pump isn’t circulating through the UFH, it’s only circulating to the buffer. There are pumps on each of the UFH manifolds that draw the heat from the buffer when one of their respective zones call. The actuators will close and the pump stop circulating once the rooms are satisfied so I’m not sure what constant circulating or overheating they are talking about. So what is setting the temperature of the buffer..? And how any manifolds do you have..??? In this design, one manifold could deliver cold water to the buffer faster than the other so you will get mismatched flows and no way of setting the actual flow of the system 6 minutes ago, pocster said: The mixers are mechanical so there is no control, they are set manually. The minimum temperature they can be set to (35C) is higher than the maximum design temperature of your system so they are practically redundant as under the design conditions the heat pump will not produce heat higher than this. Incorrect - Minimum setting on the IVAR and ESBE valves is 22-24c 7 minutes ago, pocster said: If you want to add mixers you will need to add an additional pump and control on the buffer side to take the heat from the buffer to the manifolds when either of them called. Incorrect - a manifold pump will pull from the buffer via the flow valve, as per any design (including a couple I have recently installed and commissioned that work fine...) 8 minutes ago, pocster said: Also, as the mixer wont completely close the flow temperature will need to be set higher to compensate for this mixing and increase the running costs. Incorrect - you set the mixer to the flow temperature required. The required heat to get the slab/room to the correct temperature is the same, irrespective of the flow temperature (this is the standard laws of thermodynamics) so there is no additional running cost. 10 minutes ago, pocster said: I do not recommend mixers on a low temperature system. OK so this is the crux of the issue. He doesn't recommend them, so ask him to WARRANTY that the ASHP can never exceed 35c including in a fault condition. Also, does the buffer have a backup immersion..??? Link to comment Share on other sites More sharing options...
Russell griffiths Posted July 13, 2020 Author Share Posted July 13, 2020 Had the same conversation today, told him what I’ve been told on here, he’s baffled why I want a blending valve but will send one if I’m happy to pay for it. 2 Link to comment Share on other sites More sharing options...
redtop Posted July 16, 2020 Share Posted July 16, 2020 so a summary of best practice is:- wunda do some good stuff / good prices. Don't use their wilo pump / manifold instead use the Ivar as its better at blending at low temps which provides risk reduction in the case of the ASHP going nuts and salus auto balancing valves are brill. Link to comment Share on other sites More sharing options...
Russell griffiths Posted July 16, 2020 Author Share Posted July 16, 2020 I have managed to return my manifold and pump and I have a new low temperature mixer from IVAR coming with an IVAR manifold. Supposed to be the rolls Royce version. @Nickfromwales it’s all your fault. ?? 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted July 16, 2020 Share Posted July 16, 2020 3 hours ago, Russell griffiths said: I have managed to return my manifold and pump and I have a new low temperature mixer from IVAR coming with an IVAR manifold. Supposed to be the rolls Royce version. @Nickfromwales it’s all your fault. ?? I'll be up for another BBQ shortly Link to comment Share on other sites More sharing options...
JFDIY Posted July 16, 2020 Share Posted July 16, 2020 @Nickfromwales How does the emmeti TM3-R pump set compare to the IVAR? It's a bit late as it's just gone in to my place, but interested on your thoughts, the TMV with capillary is graduated from 20-60c so I'm hoping that's a positive. Link to comment Share on other sites More sharing options...
Nickfromwales Posted July 17, 2020 Share Posted July 17, 2020 (edited) 14 hours ago, JFDIY said: @Nickfromwales How does the emmeti TM3-R pump set compare to the IVAR? It's a bit late as it's just gone in to my place, but interested on your thoughts, the TMV with capillary is graduated from 20-60c so I'm hoping that's a positive. 6 and two 3's by the look of it, just the IVAR has an in built bypass whereas the Emmeti doesn't appear to have one. Components include: Grundfos Secondary Underfloor pump Remote sensor holder Upper body Lower body Manifold 1″ connection fittings Thermometer Primary by-pass valve Secondary by-pass valve Thermostatic head SKU: PUT-IV-UNIMIX.IV Categories: Home Page, UFH Pump Control Pack - Underfloor Heating Pump Mixer Kit Related products Edited July 17, 2020 by Nickfromwales 1 Link to comment Share on other sites More sharing options...
JFDIY Posted July 17, 2020 Share Posted July 17, 2020 Thanks Nick, I've just checked, it does have a bypass, so I guess that's good. Item 2 and seems to be adjustable. Not sure the difference the setting would make, there are 5 settings 1 Link to comment Share on other sites More sharing options...
ProDave Posted July 18, 2020 Share Posted July 18, 2020 On 13/07/2020 at 15:46, pocster said: The mixers are mechanical so there is no control, they are set manually. The minimum temperature they can be set to (35C) is higher than the maximum design temperature of your system so they are practically redundant as under the design conditions the heat pump will not produce heat higher than this. Even IF they were "practically redundant" they are an essential safety feature to protect the floor from overheating IF the ASHP malfunctioned and was delivering water too hot. Do these installers also tell you the over pressure and over temperature blow off valves on an UVC are "practically redundant" so can be omitted? 1 Link to comment Share on other sites More sharing options...
Pete Posted July 18, 2020 Share Posted July 18, 2020 I have a Wunda manifold that has been waiting to be installed for 18 months and I now find I need a blending valve as I do not think there is one there at the moment so will have to contact Wunda this week!! Link to comment Share on other sites More sharing options...
Nickfromwales Posted July 18, 2020 Share Posted July 18, 2020 11 minutes ago, Pete said: I have a Wunda manifold that has been waiting to be installed for 18 months and I now find I need a blending valve as I do not think there is one there at the moment so will have to contact Wunda this week!! If it's a low-temp install then pointless as they stopped selling their low-temp blending set for whatever reason. I did try petitioning their sales director, but never got a reply. Link to comment Share on other sites More sharing options...
Pete Posted July 18, 2020 Share Posted July 18, 2020 3 minutes ago, Nickfromwales said: If it's a low-temp install then pointless as they stopped selling their low-temp blending set for whatever reason. I did try petitioning their sales director, but never got a reply. Yes it is a low temp install so are you saying it is pointless installing the existing manifold ? Link to comment Share on other sites More sharing options...
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