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Thread: Evohome Wiring Centre guidance

  1. #1
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    Default Evohome Wiring Centre guidance

    Hi there,

    My existing system:

    S-Plan
    Honeywell ST9400C 7 Day 2 Channel Programmer
    Honeywell CM907 7 Day Programmable Room Thermostat
    Honeywell Sundial Plans Wiring Centre (Part number 42005748-001)

    Does anybody have a link to wiring the Evohome modules (2 x BDR91 and 1 x CS92A) to the Honeywell Wiring Centre?

    Thanks!

  2. #2
    Automated Home Sr Member electronicsuk's Avatar
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    It all depends how you're going to run the system. If you check pages 42 and 43 of the installation guide, you'll find some sample systems. Will you be fitting a HR92 to every radiator, or having the entire home controlled as a single heating zone plus a hot water zone?

    It would also be useful to know how you are using your current system. You have a 2 channel programmer and also a 7 day programmable thermostat. You presumably aren't using the timeclock on both of these - do you leave the heating channel on the programmer set to always on, and then use the thermostat as the heating timeclock? Again, this would be useful to know to allow us to work out how your existing wiring centre is being used.

    Finally, a picture of inside the wiring centre would also be helpful. There's a definite way the 42005748-001 should be wired, but that doesn't necessarily mean that your original installed did the job correctly :P

  3. #3
    Automated Home Legend top brake's Avatar
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    you cannot use the Honeywell Wiring Centre

    Please use a 10 way junction box as depicted in the installation guide
    I work for Resideo, posts are personal and my own views.

  4. #4
    Automated Home Sr Member electronicsuk's Avatar
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    Quote Originally Posted by top brake View Post
    you cannot use the Honeywell Wiring Centre

    Please use a 10 way junction box as depicted in the installation guide
    I don't see why not. If sticking with S plan, all that would be required would be change the wiring on the room start and programmer terminals. Some of the wiring may become redundant, but that's surely no reason to change out the entire wiring centre?

  5. #5
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    Thanks for the replies, I love this forum!

    @electronicsuk, you are correct, I have the controller set to always on for the heating side, and use the programmable thermostat to control the heating. I intend to fit HR92 to every radiator (except the bathroom ones, which don't have TRVs).

    @top-brake, I think that makes sense anyway. It will help me ensure all the wiring has been done correctly. It looks very tidy as it is, and everything works perfectly, so I wanted to minimise the disruption. But if you think the Wiring Centre can't be used, then so be it.

    Thanks again guys!

  6. #6
    Automated Home Sr Member electronicsuk's Avatar
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    Rotor, can you post a picture of the inside of the wiring centre?

    EDIT: I did post some directions a few moment ago, but realised I made a bit of a ****up. Will re-post again later when I get chance to look it over.
    Last edited by electronicsuk; 10th November 2015 at 12:52 PM.

  7. #7
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    I'll take some pictures tonight.

  8. #8
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    Is it this one?

    http://s299.photobucket.com/user/ele...re420.png.html

    I think it'll give you a headache and suggest you do as top brake suggests and use a 10-way junction box. I'd also recommend that you print out the wiring diagram from the manual and stick it to the lid of the junction box should you need to go back in there in a couple of years and have forgotten what does what...

  9. #9
    Automated Home Sr Member electronicsuk's Avatar
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    I'm not sure why everyone is suggesting that re-using the existing wiring centre will be such a hardship. Seems like it should just be a case of the following:

    - Remove all wiring to existing programmer, programmable room stat and cylinder stat
    - Link out CYL STAT terminals 1 and C
    - Remove grey and orange wires from HW VALVE and HTG VALVE connections
    - Wire DWH BDR91 demand to programmer HW ON terminal, take supply from programmer L/N/E (connect as per basic boiler schematic, evo guide page 44 fig 5)
    - Wire CH BDR91 across HW VALVE or HTG VALVE orange and grey connections (connect as boiler with permanent live, evo guide page 44 fig 6). Take supply from programmer L/N/E (will need to share power terminals between the two BDR91s).
    - Set CH 2-port zone valve to permanently open (there's usually a mechanical lever on the valve that will allow you to do this)
    - Install rest of system as per Honeywell guide
    - Sit back and grab a beer
    Last edited by electronicsuk; 11th November 2015 at 02:13 PM.

  10. #10
    Automated Home Legend top brake's Avatar
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    Quote Originally Posted by electronicsuk View Post
    I'm not sure why everyone is suggesting that re-using the existing wiring centre will be such a hardship. Seems like it should just be a case of the following:

    - Remove all wiring to existing programmer, programmable room stat and cylinder stat
    - Link out CYL STAT terminals 1 and C
    - Remove grey and orange wires from HW VALVE and HTG VALVE connections
    - Wire DWH BDR91 demand to programmer HW ON terminal, take supply from programmer L/N/E (connect as per basic boiler schematic, evo guide page 44 fig 5)
    - Wire CH BDR91 across HW VALVE or HTG VALVE orange and grey connections (connect as boiler with permanent live, evo guide page 44 fig 6). Take supply from programmer L/N/E (will need to share power terminals between the two BDR91s).
    - Set CH 2-port zone valve to permanently open (there's usually a mechanical lever on the valve that will allow you to do this)
    - Install rest of system as per Honeywell guide
    - Sit back and grab a beer
    the wiring centre is designed for easy installation of wired controls

    for supported wiring diagrams please refer to the appendix of the evohome installation guide
    evohome is mostly wireless, in most cases just a few wireless relays that need to be wired to hot water motorised valve and boiler
    I work for Resideo, posts are personal and my own views.

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