Underfloor heating with Evohome

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  • watchforstock
    Automated Home Jr Member
    • Mar 2014
    • 20

    Underfloor heating with Evohome

    Hi all,

    We've had evohome for quite a while now and are very happy with it. It's connected to an S-plan vented system with separate zone valves for DHW and CH. We're about to redo our kitchen and this will entail moving from having a radiator with HR92 to (single zone) wet underfloor heating. As the people doing the work are not familiar with Evohome (and I'm not familiar with wet underfloor heating) I'm quite keen to get a clear view as to how it works.

    My current understanding is that we will connect the HCC80R to the manifold that will be installed. The HCC80R will also power (and control) the pump which will circulate the water around the underfloor loop. We would then need a sensor in the room such as the DTS92 to measure room temperature and report to Evohome. Where I get less clear is around zone valves. The builder is expecting to add a new zone valve to the system for the supply to the heating loop. I can see various references to using a BDR91 to provide a heat demand signal to the boiler so what I wanted to check was that the bits that need to be bought are 1xHCC80R, 1xDTS92 and 1x BDR91 and that all of these will be bound into a single zone when set up on the evohome as the new kitchen zone.

    The other question is whether the T87RF2025 Single Zone Thermostat can be used as a better-looking alternative to the DTS92

    Any comments on whether I'm right or wrong in the above would be welcome! (or also pointers to documents I might have missed explaining this)

    Thanks

    Andrew
    Last edited by watchforstock; 26 June 2015, 09:02 PM.
  • paulockenden
    Automated Home Legend
    • Apr 2015
    • 1719

    #2
    Can't answer your main question, although have you tried the system builder?

    As to the room stat, the T87RF looks nicer, but the DT92E has a few advantages - as well as temp sensing and control (which they both do) the square one has an Eco button (which is completely independent of the Eco setting on the evohome controller) and also a button that allows you to turn the zone off completely. The square one can also be either wall or table mounted, whereas the round one is wall only.

    But the round one does look a lot nicer. I'd probably go for that, unless you need to 'tinker' with the zone.

    P.

    Comment

    • top brake
      Automated Home Legend
      • Feb 2015
      • 837

      #3
      Originally posted by watchforstock View Post
      Hi all,

      We've had evohome for quite a while now and are very happy with it. It's connected to an S-plan vented system with separate zone valves for DHW and CH. We're about to redo our kitchen and this will entail moving from having a radiator with HR92 to (single zone) wet underfloor heating. As the people doing the work are not familiar with Evohome (and I'm not familiar with wet underfloor heating) I'm quite keen to get a clear view as to how it works.

      My current understanding is that we will connect the HCC80R to the manifold that will be installed. The HCC80R will also power (and control) the pump which will circulate the water around the underfloor loop. We would then need a sensor in the room such as the DTS92 to measure room temperature and report to Evohome. Where I get less clear is around zone valves. The builder is expecting to add a new zone valve to the system for the supply to the heating loop. I can see various references to using a BDR91 to provide a heat demand signal to the boiler so what I wanted to check was that the bits that need to be bought are 1xHCC80R, 1xDTS92 and 1x BDR91 and that all of these will be bound into a single zone when set up on the evohome as the new kitchen zone.

      The other question is whether the T87RF2025 Single Zone Thermostat can be used as a better-looking alternative to the DTS92

      Any comments on whether I'm right or wrong in the above would be welcome! (or also pointers to documents I might have missed explaining this)

      Thanks

      Andrew
      most underfloor heating manifolds don't need a zone valve but if it does simply wire it in with the UFH pump

      all covered in the youlearn training, and yes you can use Y87 round wireless thermostat, binding is covered in the evohome Wi-Fi installation guide

      a note of caution; UFH is not for the novice so recommend getting the system designed and installed by specialist.

      binding HCC80R to evohome is pretty straightforward and what is not covered in the evohome instructions is covered in the HCC80R instructions

      any queries please ask
      I work for Resideo, posts are personal and my own views.

      Comment

      • The EVOHOME Shop
        Site Sponsor
        • Dec 2014
        • 483

        #4
        Originally posted by watchforstock View Post
        Hi all,

        We've had evohome for quite a while now and are very happy with it. It's connected to an S-plan vented system with separate zone valves for DHW and CH. We're about to redo our kitchen and this will entail moving from having a radiator with HR92 to (single zone) wet underfloor heating. As the people doing the work are not familiar with Evohome (and I'm not familiar with wet underfloor heating) I'm quite keen to get a clear view as to how it works.

        My current understanding is that we will connect the HCC80R to the manifold that will be installed. The HCC80R will also power (and control) the pump which will circulate the water around the underfloor loop. We would then need a sensor in the room such as the DTS92 to measure room temperature and report to Evohome. Where I get less clear is around zone valves. The builder is expecting to add a new zone valve to the system for the supply to the heating loop. I can see various references to using a BDR91 to provide a heat demand signal to the boiler so what I wanted to check was that the bits that need to be bought are 1xHCC80R, 1xDTS92 and 1x BDR91 and that all of these will be bound into a single zone when set up on the evohome as the new kitchen zone.

        The other question is whether the T87RF2025 Single Zone Thermostat can be used as a better-looking alternative to the DTS92

        Any comments on whether I'm right or wrong in the above would be welcome! (or also pointers to documents I might have missed explaining this)

        Thanks

        Andrew
        Hi Andrew,

        In the case of a single zone UFH system (i.e. just one room) there is every chance this has been over specified. Firstly most UFH suppliers will use a manifold with combined pump/blending valve/zone valve, so in this instance there is no need for thermal actuators and the manifold ports can remain open circuit. This means there is every chance you will not need the HCC80R and can just use a Y87RF2024 or DT92E (thermostat and relay box combi) to simply switch the zone valve and UFH pump on heating demand and then the new UFH zone valve will provide switching for the boiler and heating pump. There are ways you could do all this wireless, but many mean a system configuration change and depends on the current configuration you have.

        The T87RF thermostat is a much more modern looking but DTS92 does have more features as Paul has said.

        If you would like to talk about this in further detail, you can of course give me a call.

        Many thanks,

        Richard.

        Comment

        • bruce_miranda
          Automated Home Legend
          • Jul 2014
          • 2307

          #5
          I realise I am bringing up an old thread. But I have underfloor heating on a single zone and so didn't bother with getting a HCC80R but instead just went for the normal Y87RF kit, where the T87RF room stat is bound as the sensor and the BDR91 is bound as the actuator. The BDR91 switches the motorised valve and the underfloor pump on. My question is, what should the BDR91 for this underfloor zone be bound as a Zone Valve, Underfloor heating, Radiator Valve or Mixing Valve?

          Currently it's bound as a Zone valve. Can I bind it as a Underfloor Heating? p.s. When would you use Mixing Valve?

          Comment

          • top brake
            Automated Home Legend
            • Feb 2015
            • 837

            #6
            Zone valve.
            I work for Resideo, posts are personal and my own views.

            Comment

            • bruce_miranda
              Automated Home Legend
              • Jul 2014
              • 2307

              #7
              What is a Mixing Valve and when is that used within an Evohome setup? Will a BDR91 pair as an Underfloor Heating Valve?

              Comment

              • top brake
                Automated Home Legend
                • Feb 2015
                • 837

                #8
                Electronic blending valve for mixed lower temperature circuit controlled by a HM80. Common in eu. Don't worry about it.

                No you cannot pair a BDR as UFH.

                The application type is defined by the actuator that you are binding. BDR91 = zone valve. Radiator = HR92. Underfloor = HCC80.

                All explained in the manual and on the evohome help menu.
                I work for Resideo, posts are personal and my own views.

                Comment

                • EnigmaX
                  Automated Home Lurker
                  • Jul 2015
                  • 4

                  #9
                  Originally posted by top brake View Post
                  The application type is defined by the actuator that you are binding. BDR91 = zone valve. Radiator = HR92. Underfloor = HCC80.

                  All explained in the manual and on the evohome help menu.
                  Sorry for ressurecting an old thread, but I'm faced with the same issue here. Why would I want to pay £275 for the HCC80R if I could just bind a BDR91 to a pump and use as a zone valve? What's the benefit of the HCC80 for UFH with only a single zone (i.e. a single room)?

                  Comment

                  • top brake
                    Automated Home Legend
                    • Feb 2015
                    • 837

                    #10
                    Originally posted by EnigmaX View Post
                    Sorry for ressurecting an old thread, but I'm faced with the same issue here. Why would I want to pay £275 for the HCC80R if I could just bind a BDR91 to a pump and use as a zone valve? What's the benefit of the HCC80 for UFH with only a single zone (i.e. a single room)?
                    No benefit if just a Single Zone without thermal actuators
                    I work for Resideo, posts are personal and my own views.

                    Comment

                    • bruce_miranda
                      Automated Home Legend
                      • Jul 2014
                      • 2307

                      #11
                      The HCC80R is required only if you have a single manifold serving multiple rooms and you want zone control. If you have a pump/manifold per room or zone you just buy a T87RF and use the wall stat as your sensor and the BDR91 the Zone Valve actuator.

                      Comment

                      • The EVOHOME Shop
                        Site Sponsor
                        • Dec 2014
                        • 483

                        #12
                        Originally posted by bruce_miranda View Post
                        If you have a pump/manifold per room or zone you just buy a T87RF and use the wall stat as your sensor and the BDR91 the Zone Valve actuator.
                        Don't confuse the poor man... One of these will do for a single zone of UFH - https://theevohomeshop.co.uk/honeywe...y87rf2024.html

                        Comment

                        • bruce_miranda
                          Automated Home Legend
                          • Jul 2014
                          • 2307

                          #13
                          Or if you are using an OT bridge as your boiler control then install the Evohome controller in the UFH zone itself and use it as your sensor, with the BDR91 included in the box as the actuator - just remember to clear any previous bindings. That way you don't have to buy any more kit.

                          I should have done this myself! I've now landed up with two spare BDR91s and my Evohome sensor is unused too.

                          Comment

                          • The EVOHOME Shop
                            Site Sponsor
                            • Dec 2014
                            • 483

                            #14
                            Originally posted by bruce_miranda View Post
                            Or if you are using an OT bridge as your boiler control then install the Evohome controller in the UFH zone itself and use it as your sensor, with the BDR91 included in the box as the actuator - just remember to clear any previous bindings. That way you don't have to buy any more kit.
                            Yep fine to do this too, just as long as the main controller can still communicate with all the other evohome devices on the system effectively...

                            Comment

                            • 1animal1
                              Automated Home Jr Member
                              • Jan 2018
                              • 39

                              #15
                              Another ancient thread resurrection 😁

                              I thought I'd get this in before 2019 rears its head.

                              I am running an unvented cylinder with OT Evohome and full rad valve set up on a IS32 Atag. When my heating engineer was putting everything together, I had him put an extra 22mm zone branch in, ready for a future UFH addition. I am not planning this installation and wanted to ask a further question in addition to what's been discussed above.

                              Initially I will be fitting a single zone for a kitchen, approx 12 sqft which I think should be ok on a single zone - understand I can use my spare BDR91 and my controller as a stat. This would all go through a fully integrated manifold.

                              My question is around future proofing. I want to set this up today with a view to adding at least another zone or two in the next few years. Understand I can fit it out easily as per in this thread... Presume it'll be easy enough to add the UFH Evo controller later, for which I gather I'll need an actuator per zone too?

                              Secondly, how does this interact with the current set up. I ask as recently had my hot water on a small 1:30 time slot every 48 hrs which coincided with the morning rad warm up, therefore the water didn't generally get much or any heat, solved by increasing the HW time slot - would the UFH work in conjunction with the Rads when requesting heat?

                              Thanks

                              Comment

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