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Thread: Evohome install - have I got the right idea?

  1. #1
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    Default Evohome install - have I got the right idea? Update - Wiring check

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

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

    Iím 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 Iíve read a lot of information and have been trying to summarise it for my install. Iíve 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? Iím 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.

    Itís a learning curve for sure but Iím confident and fairly competent at installing stuff. Just want to make sure itís done correctly and right first time.

    Best Regards,

    Harvey
    Last edited by Harvmate111; 18th January 2018 at 02:06 PM.

  2. #2
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    Quote 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).

  3. #3
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    Quote 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 itís taken me so long to respond, I completely forgot about this thread!

    Right so weíre in the house now and Iíve had a closer look at the installation and what is required. Currently I have:
    - Evohome controller and BDR91
    - 12 x HR92 TRVís
    - 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 doesnít look to bad. Iíve 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 Ė electrically isolated and placed to manual open.
    - Finally wire in the BDR91ís 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?


    AlsoÖfinal 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 havenít gone too wrong!

    Best Regards,

    Harvey

  4. #4
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    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?

  5. #5
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    Quote 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.

  6. #6
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    Quote 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 Iíve 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?

  7. #7
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    New diagram attached.

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

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

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

    Quote 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; 19th January 2018 at 09:45 AM.

  9. #9
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    Quote 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

  10. #10
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    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.

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