UFH - EvoHome and reluctant plumber

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts
  • eightiescalling
    Automated Home Lurker
    • Jan 2019
    • 5

    UFH - EvoHome and reluctant plumber

    Hi All,

    We're having an extension put in with wet under floor heating for the kitchen - the plumber is suggesting this is done with 3 piping runs to improve the effectiveness of it.

    I've been using the EvoHome setup across the rest of the house for a couple of years and very happy with it - the flexibility between rooms, zones, API that can be used separately to the apps etc.

    The plumber however has never dealt with EvoHome and pushing me towards HeatMiser claiming cost but then also saying it will be the same number of controllers on the manifold either way. I'd rather stick with one controlling system overall.

    I'm not familiar with the piping/manifold setup for UFH and I must admit still struggling a bit on the EvoHome vs HeatMiser parts. I was wondering whether those here that know way more than me (pretty much everybody!) could help me on the difference between the two cost wise and whether that difference gets much worse based on the 3 pipe runs.

    Thank you!

    P.S. Irrespective of any answers on this one, thanks to everyone that does help and answer threads on this forum - it's been a mine of information!
  • rvb99
    Automated Home Sr Member
    • Oct 2017
    • 74

    #2
    Since you have a single zone ( just the kitchen) the simplest and cheapest is to wire the ufh 3 manifold valves in parallel to a bdr91 also with the ufh circulation pump ( use a connection box) . You will also need a room stat such as YRf87 . This way when the kitchen zone calls for heat the bdr will open the manifold valves and kick off the circulation pump.
    We use a HCC 80 ufh controller which works flawlessly for multiple zones but you only need this if you have 2 or more ufh zones to control.

    Comment

    • BuxtonJim
      Automated Home Jr Member
      • Aug 2018
      • 45

      #3
      Completely agree with rvb99. This is precisely the route we went with a single zone UFH - works flawlessly. Didn't even need an additional sensor as the Evotouch display was already sited there.

      Comment

      • eightiescalling
        Automated Home Lurker
        • Jan 2019
        • 5

        #4
        Thanks for the feedback guys - that's exactly what I needed.

        I'm going to be needing some more HR92s anyway and while I have a DTE92 going spare that would do the same job, I do prefer the YRF87 - and it's passed the WAF test already in the lounge where there are a few rads tied to a single zone.

        rvb99 - Are there any downsides to hooking the 3 valves up in parallel? Presumably it assumes all 3 runs are equally spread etc. Assume there are no issues with the power draw from 3 valves for the relay rather than 1?

        Comment

        • rvb99
          Automated Home Sr Member
          • Oct 2017
          • 74

          #5
          Power draw from the manifold actuators and pump is negligable. In any ufh you should ensure the pipe circuit lengths are more or less the same within a few metres.

          Comment

          • bruce_miranda
            Automated Home Legend
            • Jul 2014
            • 2307

            #6
            You don't even need to invest in electronic actuators. Just leave the manifold manual ones on. As long as each circuit run is about the same length and they are all serving the same zone, then you just control the zone valve with your BDR91, which in turn controls the UFH pump. Done.

            Comment

            • eightiescalling
              Automated Home Lurker
              • Jan 2019
              • 5

              #7
              Thanks again for the feedback.

              Just to make sure I'm not over simplifying it, on the assumption that the manifold (whatever brand) is supplied with electronic actuators is it as straight forward as buying a single BDR91 and that relay wired to the actuators and pump all in parallel? Or is it one for the pump and one for the actuators?

              Then once they're wired in and the YRF87 bound against it making up the zone Evohome works its magic.

              Almost feels too easy which makes me think I'm missing something.

              Comment

              • bruce_miranda
                Automated Home Legend
                • Jul 2014
                • 2307

                #8
                Most manifolds won't come with electric actuators. So it gets simpler. You just wire the BDR91 to open the zone valve feeding the manifold, that in turn switches on the UFH pump. The T87RF becomes the remote temperature sensor.

                Comment

                • rvb99
                  Automated Home Sr Member
                  • Oct 2017
                  • 74

                  #9
                  Originally posted by eightiescalling View Post
                  Thanks again for the feedback.

                  Just to make sure I'm not over simplifying it, on the assumption that the manifold (whatever brand) is supplied with electronic actuators is it as straight forward as buying a single BDR91 and that relay wired to the actuators and pump all in parallel? Or is it one for the pump and one for the actuators?

                  Then once they're wired in and the YRF87 bound against it making up the zone Evohome works its magic.

                  Almost feels too easy which makes me think I'm missing something.

                  There are 2 techniques you can use - both only need a single BDR91. In my proposal you wire the ufh circulating pump in parallel with the actuators. When the zone requests heat via the YRF87 temp sensor the BDR will switch open up all 3 connected manifolds actuators and start the ufh pump.

                  In bruce_miranda's version you keep the manual actuators that come with the ufh manifold (3 to the underfloor pipe circuits are left open, the rest are closed) and you control the feed pipe to the ufh system using a zone control valve such as a HONEYWELL V4043H1080 2 PORT ZONE VALVE 1" BSP 6 WIRE and connect this to the BDR91. Here you have 2 further options. Either connect the ufh circulating pump to the zone valve such that the pump starts when then valve is open and stops when the valve closes OR you can wire the zone valve and circulating pump in parallel. Use of a single zone valve should be cheaper(pick up on ebay) than 3 electric actuators(one for each pipe circuit). Other things you will need of course to consider are wiring distance and piping layout and access.
                  Last edited by rvb99; 19 February 2019, 12:47 PM.

                  Comment

                  • eightiescalling
                    Automated Home Lurker
                    • Jan 2019
                    • 5

                    #10
                    Thank you both for the time taken to clarify and help me.

                    So apparently the manifold that they tend to use as standard where more than pipe run is done has electronic actuators and as it's already factored in to the price for the building works I'm not going to worry too much between the two unless there is a practical reason to.

                    That leaves your approach rvb99 as the favorite - although I like the simplicity of bruce_miranda's zone valve to pump approach.

                    As this is a new install to a room basically being assembled from ground up with all plumbing and electrics new, wiring and access are simpler - I saw one where the manifold was tucked away in a corner cupboard and a nighmare to get to. Much to my other halfs amusement I tend to insist on being able to get to these things when they're in - planned access never used is always far less painful and destructive! Similarly the pump, manifold and zone valve/BDR will all be in close proximity as a result. Uprated boiler to cater for this and other additional rads has also been done.

                    Comment

                    • BuxtonJim
                      Automated Home Jr Member
                      • Aug 2018
                      • 45

                      #11
                      Yes it was rvb99's first approach that best fitted my situation as the manifold came with electric actuators. I totally agree about the sense in keeping manifolds, pumps and wiring centres accessible and I had the luxury of siting it in a full size cellar beneath the space in question. Only problem was that the boiler is three floors above necessitating a long heat shielded connection via the CH pipework. Evohome was fitted some time after the UFH was installed. The floor is flagged so it took a bit of juggling with the schedule but now the spaces concerned are consistently dead right.

                      Comment

                      • bruce_miranda
                        Automated Home Legend
                        • Jul 2014
                        • 2307

                        #12
                        if the entire manifold is serving one heating zone, then electric actuators are completely unnecessary. They are only needed if individual runs are serving different rooms, which can be shut off from others..

                        Comment

                        • kevinsmart
                          Automated Home Ninja
                          • Sep 2018
                          • 257

                          #13
                          I have a single zone twin loop UFH setup controlled via Y87RF and BDR91 in my new well insulated extension. BDR91 activates the pump and manifold valves are left open.

                          As it’s in combination with 26 rads, there is a thermostatic mixing valve to reduce the flow temperature. Boiler is Intergas HRE40 SB with OpenTherm module, and an outdoor sensor (unfortunately weather compensation doesn’t work with Evohome OpenTherm support though).

                          I’m not happy with the UFH setup for a few reasons:

                          1. The mixing valve intermittently emits a high pitched whine, appears to be when the flow temperature matches its set point.
                          2. Wife complains about 1!
                          3. Poor temperature control. Evohome indicates a 40-60% demand for the zone even when the set point is reached, as a result there is an overshoot. Optimum start typically pre-heats for 1.5 hours, temperature increases to more than 1 degree above the set point after a few more hours, still with <20% demand, then optimum stop kicks in 1 hour before set back. I’ve tried reducing the mixing valve set point temperature but Evohome seems unable to adapt.

                          Primarily because of 2, I’m going to replace with an HM80 controlled rotary actuator and flow temperature sensor. I hope this will work better with OpenTherm and provide more accurate temperature control.

                          Comment

                          • rvb99
                            Automated Home Sr Member
                            • Oct 2017
                            • 74

                            #14
                            Im not sure fitting flow sensors and HM80 actuators will make much difference. The ufh pipes are run at fixed mixed temp or they are off. The heat regulation is a function of evohome turinîg the ufh unit and actuators on or off at set times. The manifold temp should be set such that the floor surface never gets above around 26-28 deg and the difference between in and out manifold temps are around 5-10deg . One of the issues with ufh is that it takes a long time to lean the heating requirement, because of the slow heat latency ( eg so no point tryîg to
                            set a very low night temperatures) . The other ( although this is my speculation ) is that there is a little more intelligence in the bespoke HCC80 ufh controller rather than the simpler BDR91 , the pricer former set to better control some of the above deficiencies. We get a few overshoots with the HCC80 but this is on one zone with a lot of south facimg glass. Hence if the room is at temp and we then get 3-4 hours of sun it takes a while to get back to target temp.
                            Last edited by rvb99; 26 February 2019, 08:07 PM.

                            Comment

                            • bruce_miranda
                              Automated Home Legend
                              • Jul 2014
                              • 2307

                              #15
                              I would only get the HCC80 if ever there was a need to split a single manifold into multiple zones.

                              Comment

                              Working...
                              X