Evohome in new build house with 2 zone and HW

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  • JamboV6
    Automated Home Jr Member
    • Oct 2017
    • 32

    Evohome in new build house with 2 zone and HW

    Hi, 1st post on here.
    Im looking to install Evohome into our 3yr old newbuild.
    Its a medium size 4 bedroom house with 14 rads in total. The current setup is;
    -Glow worm Flexicom 15hx boiler
    -Range Tribune HE 180litre tank with 2 heating zone valves (upstairs and downstairs) and hotwater zone valve
    -Danfoss TP9000 thermostat for downstairs and hot water (located in the hall)
    -Danfoss TP5000 for upstairs located on the landing.
    There are 7 rads downstairs and 7 upstairs, 2 of which are towel rad in the bathroom and en-suite.

    The evohome kit i have in my shopping basket is as follows;
    1 wifi connected thermostat pack - ATP921R3100
    1 wall mount - ATF600
    1 Hot water kit ATF500DHW
    3 Radiator multizone kits - HR924UK (so 12 HR92's in total)

    I plan on running the small radiator in the utility uncontrolled as well as the one in the hall but use the main panel as the thermostat in the hall, then link the 2 HR92's on the rads in the open plan kitchen diner as 1 zone. This will mean all rooms apart from the utility are zoned one way or another, does this sound ok?

    My other question is, as there is currently 2 heating zones, do i need 2 additional BDR91's to control each zone valve or is forcing them to the manual open position and just relying on the BDR91 on the boiler the norm as there is a HR92 on all but 2 rads? was thinking about hot water needing to be pumped around the house everytime 1 rad starts calling or do the pluses outweigh the minuses.
    I also plan on adding an Echo dot to the system at a later date for Alexa control.

    I've attached floor plans of the house to help

    many thanks
    James
    Attached Files
    Last edited by JamboV6; 22 October 2017, 01:23 AM.
  • mtmcgavock
    Automated Home Legend
    • Mar 2017
    • 507

    #2
    All sounds OK apart from the following -

    - The hall rad, you can't use the EvoTouch as a sensor unless you have an actuator. So you'd have to put a HR92 on the Hall rad if you were wanting to control that zone with the EvoTouch. As other wise there is nothing to control the demand/shut off, and the system won't let you set it up without an actuator.

    - Regarding the Motorised valves - the ideal situation would be to remove both of them as they won't be needed. However you are then in a situation where if you move, change the system in the future these are then gone and would need to be reinstalled. Your best way to do this would be to purchase an additional BDR91 (You don't mention a boiler relay in your purchase list, with what you're describing it would be better with one), and wire the two heating motorised valves together connected to the BDR91. Use another BDR91 as a boiler relay, and then use the third BDR91 on the Hot Water Motorised valve. By doing the following you'll be able to disconnect the S/L from the microswitch (Grey and Orange) on the motorised valves and just use the boiler relay as your demand. Then when a CH demand is created, the boiler relay will come on, and the two motorised valves will open.

    Don't forget when installing the HW kit to leave the current cylinder stat wired in (As it's a dual stat with a safety cut out) and to set it at it's highest point. You can then use the EvoHome to control your required hot water temperature, however should anything fail on the Evohome the existing stat would still cut out the demand from the boiler.

    Comment

    • JamboV6
      Automated Home Jr Member
      • Oct 2017
      • 32

      #3
      Thanks for your detailed reply.
      I didnt mention a boiler relay in my list as one comes with the Evotouch pack (ATP921R3100) so i will have a BDR91 on the boiler

      was unsure about the HR92 requirement for the hall, so thanks for clearing that up.

      So from what you are saying about the 2 CH zone valves, i'll just remove them all together, saves buying another BDR91, i need to drain the system down anyway to swap out 2 TRV bodies.

      cheers for the help.

      im away next week till 2nd week November so wont be installing till then anyway

      Comment

      • Dan_Robinson
        Automated Home Ninja
        • Jun 2012
        • 347

        #4
        Leave the valves in place, electrically isolated and locked open. Makes life easier if you need to revert the system or move house.
        Kind Regards - Dan Robinson (Jennings Heating Ltd)

        Comment

        • mtmcgavock
          Automated Home Legend
          • Mar 2017
          • 507

          #5
          Originally posted by Dan_Robinson View Post
          Leave the valves in place, electrically isolated and locked open. Makes life easier if you need to revert the system or move house.
          OP - If you aren't wanting to purchase an additional BDR91 to control the valves then this is a better way. I've left in my valves in place should I ever want to revert back to the old system, makes life easier.

          Comment

          • paulockenden
            Automated Home Legend
            • Apr 2015
            • 1719

            #6
            Didn’t someone once post that locked open zone valves are only half open?

            Was that actually true?

            P.

            Comment

            • Dan_Robinson
              Automated Home Ninja
              • Jun 2012
              • 347

              #7
              They're not fully open, but in practice, a house suitable for Evohome wireless comms is not going to be big enough for that to be an issue, or, will have multiple circuits.
              Kind Regards - Dan Robinson (Jennings Heating Ltd)

              Comment

              • bruce_miranda
                Automated Home Legend
                • Jul 2014
                • 2307

                #8
                Apparently the zone valves might seize if left in one position for too long. so what I did was wire them with the boiler pump. So they are open as long as the pump is running.

                Comment

                • JamboV6
                  Automated Home Jr Member
                  • Oct 2017
                  • 32

                  #9
                  Originally posted by mtmcgavock View Post

                  Your best way to do this would be to purchase an additional BDR91 (You don't mention a boiler relay in your purchase list, with what you're describing it would be better with one), and wire the two heating motorised valves together connected to the BDR91. Use another BDR91 as a boiler relay, and then use the third BDR91 on the Hot Water Motorised valve. By doing the following you'll be able to disconnect the S/L from the microswitch (Grey and Orange) on the motorised valves and just use the boiler relay as your demand. Then when a CH demand is created, the boiler relay will come on, and the two motorised valves will open.

                  Don't forget when installing the HW kit to leave the current cylinder stat wired in (As it's a dual stat with a safety cut out) and to set it at it's highest point. You can then use the EvoHome to control your required hot water temperature, however should anything fail on the Evohome the existing stat would still cut out the demand from the boiler.
                  Back from holiday now so would like to get this sorted in the next week.
                  Could i not wire the two heating valves to the boiler BDR91 or would that pull too much current?

                  with regards to the HW t/stat are you saying to use the danfoss one instead of the probe supplied with the honeywell kit or use it in parallel additionally?

                  thanks

                  Comment

                  • Dan_Robinson
                    Automated Home Ninja
                    • Jun 2012
                    • 347

                    #10
                    And what happens when they conk out
                    Kind Regards - Dan Robinson (Jennings Heating Ltd)

                    Comment

                    • mylesm
                      Automated Home Guru
                      • Nov 2015
                      • 153

                      #11
                      Originally posted by JamboV6 View Post
                      Back from holiday now so would like to get this sorted in the next week.
                      Could i not wire the two heating valves to the boiler BDR91 or would that pull too much current?

                      with regards to the HW t/stat are you saying to use the danfoss one instead of the probe supplied with the honeywell kit or use it in parallel additionally?

                      thanks
                      You Could do this but you make no mention of an ABV so when boiler demand ceases Zone Valves close but pump still runs on overrun so would be deadheaded without ABV

                      If the Zone Valves were Locked open then uncontrolled Rad acts as Bypass during Pump overrun

                      The simplest thing to do is just open Zone valves manually and disconnect electrically as Dan said not being fully open should not cause a problem but if you like do as i done take the heads off Zone valves and then open them fully as if the motor had opened them and leave in this position much easier than physically removing them

                      If you want to leave an uncontrolled Rad I would be more inclined to leave a Towel Rail rather than the Hall you can set temp for hall and it will be maintained by HR92 but a toasty ensuite or Bathroom is nice

                      As I understand the Existing HW Stat gets wired in series with new Stat so if New Stat Fails then Original Stat will still operate and cut Boiler Demand
                      Last edited by mylesm; 16 November 2017, 07:25 AM.

                      Comment

                      • JamboV6
                        Automated Home Jr Member
                        • Oct 2017
                        • 32

                        #12
                        Originally posted by mylesm View Post
                        You Could do this but you make no mention of an ABV so when boiler demand ceases Zone Valves close but pump still runs on overrun so would be deadheaded without ABV

                        If the Zone Valves were Locked open then uncontrolled Rad acts as Bypass during Pump overrun

                        The simplest thing to do is just open Zone valves manually and disconnect electrically as Dan said not being fully open should not cause a problem but if you like do as i done take the heads off Zone valves and then open them fully as if the motor had opened them and leave in this position much easier than physically removing them

                        If you want to leave an uncontrolled Rad I would be more inclined to leave a Towel Rail rather than the Hall you can set temp for hall and it will be maintained by HR92 but a toasty ensuite or Bathroom is nice

                        As I understand the Existing HW Stat gets wired in series with new Stat so if New Stat Fails then Original Stat will still operate and cut Boiler Demand
                        Thanks for your reply,
                        The system does have an ABV
                        The reason for keeping the utility uncontrolled is because of the size and shape of it and the radiator it doesn't matter if it heats a bit more often but also I want to be able to set the towel rail as and when independently to other rads.

                        Surely the T/Stat probes need to be in parallel, if. They are in series and one goes open circuit it will leave the probe circuit open. If In. Parallel and one fails the other will still work

                        Comment

                        • mtmcgavock
                          Automated Home Legend
                          • Mar 2017
                          • 507

                          #13
                          Originally posted by JamboV6 View Post
                          Thanks for your reply,
                          The system does have an ABV
                          The reason for keeping the utility uncontrolled is because of the size and shape of it and the radiator it doesn't matter if it heats a bit more often but also I want to be able to set the towel rail as and when independently to other rads.

                          Surely the T/Stat probes need to be in parallel, if. They are in series and one goes open circuit it will leave the probe circuit open. If In. Parallel and one fails the other will still work
                          They need to be in series, therefore if one fails (so leave the circuit closed) once the cylinder heats up the next stat in the series will open and cut off the heat source. The way you are describing would prevent this from happening.

                          Comment

                          • JamboV6
                            Automated Home Jr Member
                            • Oct 2017
                            • 32

                            #14
                            Ofcourse, wasn't thinking about it being a normally closed circuit. Nightshifts and jetlag don't make for logical thinking

                            Comment

                            • JamboV6
                              Automated Home Jr Member
                              • Oct 2017
                              • 32

                              #15
                              So I ordered all the parts last night, just need to work out the wiring, please see attached image for my current setup.

                              final parts list was;
                              -main wifi control inc BDR91
                              -13 x HR92 rad valves
                              -hotwater kit inc BDR91
                              -wall mount kit
                              -extra trv valve body
                              Attached Files

                              Comment

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