Evohome install - have I got the right idea?

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  • Harvmate111
    Automated Home Jr Member
    • Dec 2017
    • 10

    Evohome install - have I got the right idea?

    Hello everyone. Hope you all had a good Christmas and New Year.

    Right I’ve been reading a lot of posts on here about Evohome and have subsequently bought a pack with Evohome controller and 12 TRVs.

    I’m moving into a new build on Friday where the system will be installed. The boiler is a Worcester Bosch Greenstar Ri (not entirely sure on model number) and has a Range Tribune XE unvented hot water cylinder in the upstairs airing cupboard. It appears that the system is S Plan Plus - 2 CH zones (1 upstairs, 1 downstairs) and a HW zone. These are controlled by Danfoss controllers, again 1 upstairs and 1 downstairs. There is a temperature thermostat in the hallway. All rads have TRVs apart from the hallway rad.

    As I say I’ve read a lot of information and have been trying to summarise it for my install. I’ve made the following points:

    1. Remove/disconnect the Danfoss control panels upstairs and downstairs. Disconnect thermostat in hallway.
    2. Fit BD91 in place of the existing control panel as it is next to boiler.
    3. Electrically isolate and manually open both CH zone valves.
    4. Install HR92 TRVs to all radiators in house (apart from hallway as does not have a TRV and can use it as the bypass).
    5. Setup Evohome zones and other general installation stuff.

    Does this sound about right? I’m a little confused as to how to operate the HW or will I need to purchase the Evohome HW kit straight away. I was hoping I could just run it without the HW kit for a couple of months.

    It’s a learning curve for sure but I’m confident and fairly competent at installing stuff. Just want to make sure it’s done correctly and right first time.

    Best Regards,

    Harvey
    Last edited by Harvmate111; 18 January 2018, 03:06 PM.
  • mtmcgavock
    Automated Home Legend
    • Mar 2017
    • 507

    #2
    Originally posted by Harvmate111 View Post
    Hello everyone. Hope you all had a good Christmas and New Year.

    Right I’ve been reading a lot of posts on here about Evohome and have subsequently bought a pack with Evohome controller and 12 TRVs.

    I’m moving into a new build on Friday where the system will be installed. The boiler is a Worcester Bosch Greenstar Ri (not entirely sure on model number) and has a Range Tribune XE unvented hot water cylinder in the upstairs airing cupboard. It appears that the system is S Plan Plus - 2 CH zones (1 upstairs, 1 downstairs) and a HW zone. These are controlled by Danfoss controllers, again 1 upstairs and 1 downstairs. There is a temperature thermostat in the hallway. All rads have TRVs apart from the hallway rad.

    As I say I’ve read a lot of information and have been trying to summarise it for my install. I’ve made the following points:

    1. Remove/disconnect the Danfoss control panels upstairs and downstairs. Disconnect thermostat in hallway.
    2. Fit BD91 in place of the existing control panel as it is next to boiler.
    3. Electrically isolate and manually open both CH zone valves.
    4. Install HR92 TRVs to all radiators in house (apart from hallway as does not have a TRV and can use it as the bypass).
    5. Setup Evohome zones and other general installation stuff.

    Does this sound about right? I’m a little confused as to how to operate the HW or will I need to purchase the Evohome HW kit straight away. I was hoping I could just run it without the HW kit for a couple of months.

    It’s a learning curve for sure but I’m confident and fairly competent at installing stuff. Just want to make sure it’s done correctly and right first time.

    Best Regards,

    Harvey
    Sounds about right, but unless you are going to leave the existing time-clock in place to control the hot water you will need the Hot Water kit for Evohome (Remembering to leave the existing High Limit stat on the cylinder wired in).

    Locking the valves open on the Danfoss valves should be fine too as these are fully open when manually opened (unlike other brands).

    Comment

    • Harvmate111
      Automated Home Jr Member
      • Dec 2017
      • 10

      #3
      Originally posted by mtmcgavock View Post
      Sounds about right, but unless you are going to leave the existing time-clock in place to control the hot water you will need the Hot Water kit for Evohome (Remembering to leave the existing High Limit stat on the cylinder wired in).

      Locking the valves open on the Danfoss valves should be fine too as these are fully open when manually opened (unlike other brands).
      Sorry it’s taken me so long to respond, I completely forgot about this thread!

      Right so we’re in the house now and I’ve had a closer look at the installation and what is required. Currently I have:
      - Evohome controller and BDR91
      - 12 x HR92 TRV’s
      - Evohome hot water kit with BDR91

      Looking at the cylinder and valves, it appears that there is no spare access port on the Range Tribune XE unvented cylinder. There also looks to be 4 temperature probes in the probe mounting boss meaning all holes in that are used. What is the best way of getting around this? Would it be easiest to remove the immersion heater probe, isolate the immersion heater and install the evohome probe in its place? Or, could I mount the probe onto the brass mounting boss using thermal paste/compound?

      Installation / wiring wise it doesn’t look to bad. I’ve drafted up a quick schematic to note where I believe the wiring needs to go.
      - The first steps are to remove all wiring in the wiring centre that are associated with the Danfoss TP9000 and TP5000 (of which there are quite a lot).
      - Then remove the wiring to do with the Yellow and Red plugs as these are the heating zone valves which will be made redundant – electrically isolated and placed to manual open.
      - Finally wire in the BDR91’s for the Boiler and Hot Water.

      The current installation / wiring diagram and pics:

      IMG_9052.jpgIMG_9053.jpgIMG_9054.jpgIMG_9055.jpg

      The proposed wiring schematic:

      Wiring Diagram.jpg

      Does this look right and the thermostat wired in series so that the Evohome HW kit controls the water and the existing thermostat set high as a fail safe?


      Also…final question. The current installation uses a common from the TP9000 controller that is linked to the thermostat. Where can I now bring this common in from if I remove the TP9000?

      Hope I haven’t gone too wrong!

      Best Regards,

      Harvey

      Comment

      • Harvmate111
        Automated Home Jr Member
        • Dec 2017
        • 10

        #4
        Bump - Any Help as I’m looking at doing it on Sat.

        The thing I can’t quite get my head around is on the wiring schematic I’ve done - how does the boiler start up for the hot water as the orange and grey wires are redundant. Do I need to use the orange wire to boiler switched live?

        Comment

        • mtmcgavock
          Automated Home Legend
          • Mar 2017
          • 507

          #5
          Originally posted by Harvmate111 View Post
          Bump - Any Help as I’m looking at doing it on Sat.

          The thing I can’t quite get my head around is on the wiring schematic I’ve done - how does the boiler start up for the hot water as the orange and grey wires are redundant. Do I need to use the orange wire to boiler switched live?
          Your cylinder stat is wrong, B from the HW relay should go to common, then either 1 or 2 (Whichever breaks on reaching temp, usually 1) from the cylinder stat should go to the motorised valve. Without the Grey and orange wires to fire the boiler, the other relay you have needs to be configured as a boiler relay and that will fire the boiler on a HW demand along with firing the boiler on a CH demand.

          Comment

          • Harvmate111
            Automated Home Jr Member
            • Dec 2017
            • 10

            #6
            Originally posted by mtmcgavock View Post
            Your cylinder stat is wrong, B from the HW relay should go to common, then either 1 or 2 (Whichever breaks on reaching temp, usually 1) from the cylinder stat should go to the motorised valve. Without the Grey and orange wires to fire the boiler, the other relay you have needs to be configured as a boiler relay and that will fire the boiler on a HW demand along with firing the boiler on a CH demand.
            Thank you for your help I really appreciate it. So to make sure I’ve understood correctly:

            - B from HW BDR91 goes to a terminal with Common from cylinder thermostat.
            - 1 from thermostat (white wire) goes to a terminal with Br (Brown wire) from DHW Zone valve.
            - BDR91 wired to switched live for boiler setup as boiler relay.
            - HW BDR91 setup as a valve relay.

            Does 2 from the thermostat need to be wired to anything?

            Comment

            • Harvmate111
              Automated Home Jr Member
              • Dec 2017
              • 10

              #7
              New diagram attached.

              C4B20D91-076C-4A8C-BD37-5A2002F72BA8.jpg

              Does this look right now? Makes sense in my head anyway!

              Comment

              • Edinburgh2000
                Automated Home Guru
                • Dec 2016
                • 134

                #8
                Originally posted by Harvmate111 View Post
                Does this look right now?
                Yes.

                Originally posted by Harvmate111 View Post
                how does the boiler start up for the hot water as the orange and grey wires are redundant. Do I need to use the orange wire to boiler switched live?
                No. Your proposed setup uses the Boiler BDR91 to switch the boiler and pump. You do not need to connect the orange wire from the DHW valve to anything, so your diagram is correct. (But if your valve is a motored version, rather than a spring return, then you will need to connect the grey wire to a permanent live (terminals 1B or 2B)).
                Last edited by Edinburgh2000; 19 January 2018, 10:45 AM.

                Comment

                • Harvmate111
                  Automated Home Jr Member
                  • Dec 2017
                  • 10

                  #9
                  Originally posted by Edinburgh2000 View Post
                  Yes.



                  No. Your proposed setup uses the Boiler BDR91 to switch the boiler and pump. You do not need to connect the orange wire from the DHW valve to anything, so your diagram is correct. (But if your valve is a motored version, rather than a spring return, then you will need to connect the grey wire to a permanent live (terminals 1B or 2B)).
                  Understood thank you very much. I believe it’s a spring version but will double check.

                  Looking forward to getting it installed and working!

                  Harvey

                  Comment

                  • G4RHL
                    Automated Home Legend
                    • Jan 2015
                    • 1580

                    #10
                    I left my immersion element in my cylinder in case I ever need to heat water that way but have it switched off. I used the sensor that came with the hot water kit - one where it is fastened to the outside about one third up from the bottom. Works fine.

                    Comment

                    • Harvmate111
                      Automated Home Jr Member
                      • Dec 2017
                      • 10

                      #11
                      Originally posted by G4RHL View Post
                      I left my immersion element in my cylinder in case I ever need to heat water that way but have it switched off. I used the sensor that came with the hot water kit - one where it is fastened to the outside about one third up from the bottom. Works fine.
                      I’ve got an unvented tribune xe pre-plumber cylinder though. So it’s encased in a plastic cover. It doesn’t seem to have any spare ports neither to tap into. I’ve got 4 probes going into the ‘thermostat manifold’ near the bottom of the tank. 2 is for the cylinder stat and 2 for the immersion. Still unsure with how I’m going to do it yet! Any ideas?

                      Comment

                      • mtmcgavock
                        Automated Home Legend
                        • Mar 2017
                        • 507

                        #12
                        Originally posted by Harvmate111 View Post
                        I’ve got an unvented tribune xe pre-plumber cylinder though. So it’s encased in a plastic cover. It doesn’t seem to have any spare ports neither to tap into. I’ve got 4 probes going into the ‘thermostat manifold’ near the bottom of the tank. 2 is for the cylinder stat and 2 for the immersion. Still unsure with how I’m going to do it yet! Any ideas?
                        Isn't their room to push it in? Or even where you take the covers off to see the wiring can't you see any part of the insulation of the cylinder? Your picture isn't that great.

                        Comment

                        • Harvmate111
                          Automated Home Jr Member
                          • Dec 2017
                          • 10

                          #13
                          Originally posted by mtmcgavock View Post
                          Isn't their room to push it in? Or even where you take the covers off to see the wiring can't you see any part of the insulation of the cylinder? Your picture isn't that great.
                          Nope no room to push it in as all 4 pockets are taken. I’ve just looked and 1 goes to the cylinder stat and 3 of them do to the immersion heater. Taking off the cover you only see the stainless outer core. I mean I could drill a small hole into the outer core, and push the Evohome thermostat up between the cylinder and insulation but I’d rather not go down that route if I can help it.

                          Might be easier to isolate the immersion heater and use one of the pockets from that for the Evohome? Can’t see a need for the immersion heater unless in an emergency and our boiler breaks down. In that case I can reinstall the immersion thermostat and re-energise?

                          Comment

                          • mtmcgavock
                            Automated Home Legend
                            • Mar 2017
                            • 507

                            #14
                            Originally posted by Harvmate111 View Post
                            Nope no room to push it in as all 4 pockets are taken. I’ve just looked and 1 goes to the cylinder stat and 3 of them do to the immersion heater. Taking off the cover you only see the stainless outer core. I mean I could drill a small hole into the outer core, and push the Evohome thermostat up between the cylinder and insulation but I’d rather not go down that route if I can help it.

                            Might be easier to isolate the immersion heater and use one of the pockets from that for the Evohome? Can’t see a need for the immersion heater unless in an emergency and our boiler breaks down. In that case I can reinstall the immersion thermostat and re-energise?
                            Are you sure one of them isn't for the high limit stat, they usually have a probe each one, so cylinder stat and then high limit stat. In which case you need to leave in. Personally without seeing it I cannot offer my opinion however i'd be leaving my immersion wired in and intact.

                            Comment

                            • HenGus
                              Automated Home Legend
                              • May 2014
                              • 1001

                              #15
                              Originally posted by mtmcgavock View Post
                              Are you sure one of them isn't for the high limit stat, they usually have a probe each one, so cylinder stat and then high limit stat. In which case you need to leave in. Personally without seeing it I cannot offer my opinion however i'd be leaving my immersion wired in and intact.
                              Similar problem with my Oso cylinder. The installer removed the electrical cover and pushed the sensor up at an angle between the insulation and the cylinder with some flux. Taped the wire and it has worked fine for 4 years. The two existing unvented stats have been wired in series with Evohome.

                              Comment

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