Drayton Wiser kit 3, dual zone CH issue

Discussion in 'Plumbing and Central Heating' started by sahar, 9 Nov 2021.

  1. sahar

    sahar

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    hi
    Purchased Drayton Wiser kit3 to replace Siemens RWB29 in the house with HW cylinder, and two CH zones controlled by wired therms atm.
    The house was build in 2015 so guessing the wiring should be done up to the latest standards (?)

    I have replaced the control unit with Wiser hub, and HW is fine, also able to switch CH on, however no way to control upstairs downstairs.
    there was only 1 wire for CH connected to the existing backplate, and I see that the both thermostat wires go to wiring box near the HW cylinder upstairs (no description what is what in the wiring box whatsoever, it is Myson MWB16)
    I have turned both to 30degress to ensure CH does go on, however what do I need to do to be able to have dual zone control from Wiser?

    Should there be another wire connected to the back plate for the second CH channel of the HUB going back to the wiring box ?
    If so then I am screwed, as no way I can add another wire...

    Hope it all makes sense, and would appreciate any pointers.

    thanks
     
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  3. CBW

    CBW

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    Photos would help to better understand your setup. Take one of the wiring center and one of the hub.
     
  4. sahar

    sahar

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    of course

    1 - CH (was originally in 4 for Siemens)
    2 - HW (was orinally in 3)

    in the box, 3rd wire from the left bottom (marked 6) is the CH one coming from the backplate

    Think 1st left bottom and top right are the ones coming from the thermostats and then back to the valves for separate zones ...this as far as I got


    IMG_20211109_121019.jpg IMG_20211109_121120.jpg IMG_20211109_121814.jpg IMG_20211109_121834.jpg
     
  5. CBW

    CBW

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    Hmm, I’m not entirely sure as my electrical wiring on heating isn’t the best, but you may be able to link the CH on terminals, but then be controlled by the thermostats and zone valves. If nobody else can confirm (which I’m sure they can) then it might be worth a call to Drayton.
     
  6. ericmark

    ericmark

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    There are four Drayton Wiser bases upload_2021-11-9_12-35-34.png plus upload_2021-11-9_12-36-7.png as far as I understand the OpenTherm will only work with the single channel design. So no real point using OpenTherm module with three channel.

    The Siemens upload_2021-11-9_12-40-40.png instructions I have found are two channel, there are not many three channel systems, EPL it seems does one where thermostats are set as master/slave and can do up to 10 channels with OpenTherm, but I can't answer your question as can't understand how the Siemens did three channels to start with?

    May be there is a diagram on the back of thermostat, and there is one I am unaware of.

    In the main the controller be it timer, or programmable thermostat works the motorised valves, and the valves in turn work the boiler, except with EPL or Drayton single channel where the boiler is controlled with OpenTherm and the motorised valves by the controller.

    The wire colours in the main mean nothing, except for the motorised valve, so upload_2021-11-9_12-50-59.png
    Numbered from top
    2) Likely neutral
    3) Likely switches boiler on
    4) 5) 6) Likely the three channels
    But would need to test to confirm, if it were me the Drayton unit would go next to that junction box, and seems likely 1) is line in, but would need to get the meter out to confirm.

    Likely there are wiring diagrams on the lid or back of Siemens unit, same with Drayton.
     
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  8. sahar

    sahar

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    I was thinking about looping 1 and 3 on the back plate so that I am able to turn CH on from the app for either channel, but this is just testing the app and the hub, and all heating will be on then anyway (assuming both wired stats set to max)

    The separe zone temp control will still not be available via dryton wifi thermostat but the current wired ones.
     
  9. CBW

    CBW

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    @ericmark the Siemens would have been just heating on/off and the switching to zone valves done via the thermostats which would be live and switched.
     
  10. ericmark

    ericmark

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    I see two motorised valves, if only two then either central heating not zoned, or the domestic hot water is direct from boiler. To be frank can't see point in zone valves with most homes, in my main house we have 4 rooms up/stairs which we use two as bedrooms, one as craft room and one as office, and down stairs three rooms, living room, dinning room, and kitchen. I can see point of only heating bedrooms at night, but want office and craft room during the day, so the Drayton TRV heads would be ideal, no point in zone valves, I do use a zone valve for flat under main house as rarely used.

    So would seem to make sense if house is zoned to combine the zones. The TRV heads do the zoning now. But I can only guess what is there, have no way to be sure.
     
  11. sahar

    sahar

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    there is a 3rd motorized valve by the hot water cylinder too

    So just to confirm, there is no way I can get the second channel working using the current backplate wiring? Siemens was two channel only, zone valves controlled by thermostats in this set up.

    Is the ericmack's suggestion viable though ie, move control hub near the wiring box, wire it up from there, removing wired stats and get the two channels CH controled from the hub then? Would need backplate to be redone too .
    Not something I will be able to do myself, but at least gives me option to keep this 3 channel Wiser controller. would be the same issue with Hive anyway (first choice but decided against due to two controllers need so may stick to drayton if can actualyl use its functions
     

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