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Hive installation - issue with old room stat wiring

Discussion in 'Plumbing and Central Heating' started by AvgJoe, 14 Apr 2021.

  1. AvgJoe

    AvgJoe

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    Afternoon,

    I recently decided to install Hive active heating (thermostat + receiver + hub) as the old thermostat was making a buzzing noise. I managed to set it up and HW works fine, but the old room stat (which itself is disconnected now) or rather it's existing wiring which is still connected is interfering and essentially we've got no CH.

    I took photos of the wiring centre in hope someone experienced is able to help putting this right.

    The valve is Danfoss HPA2 2 port valve actuator.

    Regards,
    AJ
     

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  3. ianmcd

    ianmcd

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  4. ericmark

    ericmark

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    The brown, blue, orange, grey cable is throwing me, for a three port valve I would have expected a white wire as well and for a two port would expect to see two sets of cables one for DHW and one for CH.

    So it could be a C Plan, but I can't work out from what you have posted.
     
  5. AvgJoe

    AvgJoe

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    Apologies Eric, I think I ommited some important info, not by choice though but rather due to my own ignorance :(

    The boiler is Greenstar 24i and we also have a Megaflo water heater which has got a Honeywell 272848 motorized valve fitted.
     
  6. ianmcd

    ianmcd

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    Forget what eric has said, your boiler is very different from standard set ups, forget you have a 2 port zone valve, it is there as a safety device, do not touch the wiring to it, post a pic of the existing wiring in the existing room stat, do not follow other posts on here for installing a Hive, you need a single channel hive and no links , once you have posted the existing wiring we will tell you how to wire the receiver in
     
  7. ericmark

    ericmark

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    Thank you @ianmcd it did seem odd specially as there seems to be no neutral connected to motorised valve. When I saw "Megaflo water heater" I did think this was a special. Would be interesting to know how it works, is there some link I can't see?
     
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  8. ianmcd

    ianmcd

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    that boiler has internal zone valves that are powered by the boilers electronics, the 2 port valve is wired into the over heat stat from the cylinder to close and stop an over heat situation should the boilers sytem fail (same reason you cant use a MOMO on an unvented, well you can but you must use a spring return also) it is possible to use a hive with this boiler but not straight forward like most systems
     
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  9. AvgJoe

    AvgJoe

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    Sounds like I should've done more research as I got a dual channel Hive thinking it was the one that was needed.
    Do I need to return and get a single channel version or can this still be used?

    The old programmer for both CH&HW was Danfoss FP715Si [pic 3] and room stat was Danfoss RMT 230 [for wiring see pic 4].
     

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  11. Johnmdc

    Johnmdc

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    The Hive dual channel receiver will just replace the existing clock the connections are all the same.
    To do away with the thermostat you need to disconnect the brown wire in number 2 and the grey in number 4 and the black wire that is also in the same cable.
    Then move the blue wire with red sleeving that is in number 2 to number 4 to join the brown wire from the 2 port valve.
     
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  12. ianmcd

    ianmcd

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    Do not touch any wiring to do with the 2 port valve
     
  13. AvgJoe

    AvgJoe

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    I'm pretty sure that I did exactly this (apart from removing the black wire) when I attempted it first time, but this way the CH sort of follows HW schedule rather than being independent - it could be that the black wire interferes here though so I'll attempt at removing it tomorrow.

    Attached is current Hive receiver wiring which, as John have said, is pretty much like for like [when comparing to pic 3].

    Thanks Ian, but can you expand on this please? Is the 2nd step of what John suggested unnecessary?
     

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  14. Johnmdc

    Johnmdc

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    He has 2 x 2 port valves.
    The Danfoss one he shows wired into the wiring centre for the heating, and he says that he has a honeywell one at the cylinder.
    It just sounds like a standard S plan to me.
     
  15. Johnmdc

    Johnmdc

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    There is a neutral connected to the valve, you can see the blue wire connected in the middle of the wiring centre!
     
  16. AvgJoe

    AvgJoe

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    Morning John,
    Big thanks for your solution - as said earlier I initially rewired almost exactly the same but left the black wire from room stat still connected and it was the reason it kept on failing. Now it's working as intended, happy days!
     
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