Managing UFH Manifold and Mixing Valve

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  • Paul_B
    Automated Home Legend
    • Jul 2006
    • 608

    Managing UFH Manifold and Mixing Valve

    For over a year now I've been (very) slowly converting a room to be much more energy efficient by increasing insulation and airtightness. The plasterboard has been replaced with Variotherm Radiant Panels (18mm Fermacell boards with UFH pipes modelled into the board).

    Now I need to connect the new manifold to supply the panels (~30-40deg C) to the existing heating system (60-80degrees C). I have the manifold but need to add a mixing valve and pump. In addition I'd like to control the setup via Cortex. Has anyone blogged, documented or had experience of setting up such a system with Idratek and Cortex?

    Paul
  • Paul_B
    Automated Home Legend
    • Jul 2006
    • 608

    #3
    Cheers Chris I'll check these out tonight when I can give the docs the attention they deserve. Out of interest why have you chosen to go manifold less?

    Paul

    Comment

    • chris_j_hunter
      Automated Home Legend
      • Dec 2007
      • 1713

      #4
      manifold-less because they are expensive & a fiddle to balance & inefficient in terms of flow pressure-drops & turbulence ... plus Idratek / Cortex allows a smarter approach than has been possible before ...

      the Wilo pump self-regulates based on pressure drop, and the Sauter valves + controls respond to 0-10V, allowing good switching & regulation, zone by zone ...

      and no room thermostats (large time-lags & difficult to position representatively), but using temperature sensors* on feed & return legs to get more immediate feedback on heating demand (cooler return / larger temperature difference = more heat taken out = more heating needed) ...

      * eg:

      Last edited by chris_j_hunter; 25 August 2009, 11:55 AM. Reason: typos
      Our self-build - going further with HA...

      Comment

      • Paul_B
        Automated Home Legend
        • Jul 2006
        • 608

        #5
        Chris,

        Do you have a reference diagram for how this works? I'm struggling to try and picture it in my mind. Would you have a single circuit or multiple circuits? If the latter how do you control the distibution of heated water, is it centrally or on a ring?

        Paul

        Comment

        • chris_j_hunter
          Automated Home Legend
          • Dec 2007
          • 1713

          #6
          ideally multiple off-takes from thermal store ... else splitter just off the store ... with one pump & one valve per zone & two temperature sensors per zone ...

          BTW, AIUI, sensing return temperature, rather than having room thermostats, is not uncommon on the Continent ...

          DPS website has useful info' - would give you a link, but their web-site doesn't work that way, so you'll have to dig !
          Our self-build - going further with HA...

          Comment

          • Paul_B
            Automated Home Legend
            • Jul 2006
            • 608

            #7
            Chris,

            Thanks for the info, managed to find a specific URL relating to UFH options:


            My problem is that I am renovating over time so I have both radiators and now radiant panels. From my brief reading the 'best' option looks like an injection based system?

            I'm still a bit unsure as to whether I need to install multiple valves at a central location which then feed the individual rooms (is this very different from a manifold?) or a supply loop that has valves along the loop for feeding rooms?

            Paul

            Comment

            • chris_j_hunter
              Automated Home Legend
              • Dec 2007
              • 1713

              #8
              looks like DPS have (just) updated their website - better than it was & must have happened in the last week or two !

              injection system, yes ... 'though we've taken it as encouragement & then thought it out anew ...

              whatever, if you have the manifold, you might as well use it, I guess ! Not cheap, and will take time to set up, for best efficiency - to do it well, with a reasonable compromise, anyway - ie: v.long time-lags & difficulties in measuring what's going on ... good luck !

              OTOH, our approach is yet to be proven ....
              Last edited by chris_j_hunter; 26 August 2009, 02:01 PM.
              Our self-build - going further with HA...

              Comment

              • MrFluffy
                Automated Home Sr Member
                • Aug 2005
                • 79

                #9
                Done it, but not with idratek...
                Last house had a manifold wirsbo system, and I switched the power lines from the transformer to the manifold solenoids with a pc relay switchbox as the relays are wax capsule ones, and work on some odd ac voltage to melt the wax to open.
                I then ran a serial network right round the house, and fitted ds1820 ibuttons (about £2 apiece) behind standard socket blanking patresses and connected the serial network back to the same computer (a dead pentium 100 laptop with a broken screen).
                I then installed linux onto the laptop, and wrote some rough software to watch the serial inputs and compare them to a database of temperatures for each room and switch the inputs corresponding to the manifold valve in that zone when it needed to go one way or the other.
                I used a vellerman k74 relay box on the parport to do the switching which came with sourcecode, and used the FUSE module to patch the ds1820's connected via a link45 controller, so they presented as text based files in the linux filesystem that my scripts could read easily.

                I wrote a quick web based gui to allow people to see what temperature each room was, what the trend for the day/month/week/year was, how well the desired temp followed the actual temp (so we could identify stuck valves quickly and other issues) and also a way to burrow down into each room, and set the desired temperature on a daily basis at a 15 minute resolution.

                Its ran happily for the past 5 years, without faltering and cost well under £150 to implement the sensor and switching part of the solution. Its now running the house for a tennant who's not really pc literate but loves it and my wife has asked me to do the same system for our new house, and throw the expensive wirsbo control system in the spares bin that came with the ufh kit...
                I never pressure balanced the system for flow or anything, probably should have but it just seemed to work...

                Id like to do it with idratek and linux instead of the serial network but only because a wiring fault on the ds1820's can bring the whole serial bus down.


                When something has such WAF that she insists you fit it again, you know it was right...

                Comment

                • MrFluffy
                  Automated Home Sr Member
                  • Aug 2005
                  • 79

                  #10
                  The mixer thing is a seperate issue, to elaborate. It just blends water between the outflow and the intake to gain the desired temperate to run the ufh system.
                  It should be mechanical and just consist of a thermostatic blending valve on a flowback loop between input and outflow from the two manifolds. Our first house didnt even have one, although this time around I am going to do so to stop tank variance in temperature skewing things (we ran a solar system for heatsource, and some days the temp of the water from the tank could get into the 90's).
                  Fit this loop with a bypass system too, so when your computer controlled ufh system closes all the zones, the flow still has a route to take so it doesnt strain the pump. Or put the pump power under control of the pc and disable it when no demand is present (thought about this, but never did it, might this time round for more power savings)

                  Another aspect to think about, you have a radiator system and corresponding heating, fit the cooler return from the radiator system into the ufh manifolds as flow, it will not have cooled down past the point of being correct for the ufh input.

                  Comment

                  • RichardC
                    Automated Home Jr Member
                    • Mar 2009
                    • 29

                    #11
                    Originally posted by MrFluffy View Post

                    When something has such WAF that she insists you fit it again, you know it was right...
                    My wife now simply asks then I start going on about how some bit of tech will be so much better, "What will the WAF be then?"

                    I am just sorting out quotes at the moment for a 15 zone UFH system, two manifolds. With a couple of loops going in first as it's a renovation, somewhat over the top sensor arrangement to see what method of controlling the room works before rolling it out throughout the house. Using Idratek to control it. Lots of learning to do.

                    Comment

                    • __CA__
                      Automated Home Jr Member
                      • Aug 2009
                      • 13

                      #12
                      I've read this thread with interest as I'm currently putting in a completely new central heating system with 3 zones:

                      1st and 2nd floor radiators (bedrooms and bathrooms)
                      Ground floor radiators (living rooms and hall)
                      Ground floor UFH (kitchen)

                      It will also have an unvented hot water cylinder with a secondary return pump so that you don't have to run the hot taps for ages before they deliver hot water (controlled via a timeclock if not automated).

                      I only decided to bite the bullet and go with Idratek for lighting in the last couple of weeks, and since then I've been thinking 'why not do the heating as well from the start?'.

                      Apart from the obvious need for Idratek temperature sensors within each of the 3 zones, I think what I need for the conventional part of the CH and HW system is:
                      • 2 relays for the CH (radiator) zone valves
                      • 1 relay for the hot water valve
                      • 1 relay for the boiler
                      • Digital input to know whether the hot water cylinder is above/below desired temperature
                      • 1 relay for the secondary return pump (can be controlled via presence in each of the rooms with a hot water tap)


                      But when it comes to the UFH I'm not so sure. The spec from Polypipe says there will be a pump, 5 actuators, a 'single zone control pack' and a '4 zone slave pack'. Presumably this means the 5 actuators will all be switched together, so I only need one relay for the pump and another for the actuators?

                      All advice gratefully received

                      Thanks

                      Comment

                      • Viv
                        Automated Home Ninja
                        • Dec 2004
                        • 284

                        #13
                        [QUOTE=

                        But when it comes to the UFH I'm not so sure. The spec from Polypipe says there will be a pump, 5 actuators, a 'single zone control pack' and a '4 zone slave pack'. Presumably this means the 5 actuators will all be switched together, so I only need one relay for the pump and another for the actuators?

                        You say its just your kitchen that has under floor heating. This means you would only be using one valve on the UFH manifold and the pump. So for these two relays are required.

                        Viv

                        Comment

                        • JonS
                          Automated Home Guru
                          • Dec 2007
                          • 202

                          #14
                          Originally posted by __CA__ View Post
                          I've read this thread with interest as I'm currently putting in a completely new central heating system with 3 zones:
                          This sounds very familar, the difference in my set-up is no HW recirculation & full UFH on the ground floor. I currently have a conventional set of controls, and intend to add automation to run in parallel so I can switch between the 2 should I need to. The drivers for this are WAF, not freaking out plumbers who are very conservative and will blame new stuff for anything & to aid saleability in (many) years time.
                          I am planning relays for
                          each zone valve (2CH 1HW)
                          each UFH zone
                          UFH pump
                          boiler (system boiler so includes pump)
                          I think the zone valves will be OK with DRB/QRI relays, not sure if the boiler and pump need something with a higher rating.
                          For the HW cylinder I intend to re-use the standard thermostat, as this wll switch the Zone Valve safely and I am sure I can sense when this has occured -else use the thermostat as a volt-free switch and feed to DI.

                          On the orginal topic of manifold for mixing - I've got a standard manifold with mixer valve, its all mechanical and works, plumbers understand it, and it means the UFH pipes don't get over heated & perish quickly.

                          HTH
                          JonS
                          JonS

                          Comment

                          • MrFluffy
                            Automated Home Sr Member
                            • Aug 2005
                            • 79

                            #15
                            Originally posted by JonS View Post
                            On the orginal topic of manifold for mixing - I've got a standard manifold with mixer valve, its all mechanical and works, plumbers understand it, and it means the UFH pipes don't get over heated & perish quickly.
                            Just a tiny point, and something Ive only just realized recently.
                            You have to have the pump under control of the system or eventually the water returning from the floor will raise up the "cold" water that the blender mixes in, thus causing the temperature to creep up past what its set to. So when the floor stops demanding heat and turns off the solenoids, the blender doesnt have cold water to blend in and starts to run away thermally.

                            The light went on when we were looking into a issue with our current install while commisioning it, which unlike the weak solar/electric water heating system at the old house uses a multifuel (wood/oil at the moment) furnace (50Kw hs tarm) which is so overspec'd it can heat the house, the workshops and some outbuildings and still not be at full capacity. Now we've got 90-100deg water circulating in the main loop blended down to 40 for the floor, and the control pack was switching off the actuators for the three zones and it would go into manifold bypass, and a thermostat on the loop bypass circuit would go to 80+ degrees when the blender ran out of cold to blend in. At which point all the circulators were turned off on the ufh circuit...

                            If you have one of the valves which blocks flow above a certain temperature, then you have a second safety system which stops the above already...

                            Comment

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