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Thread: Evohome with multiple BDR91's and underfloor heating

  1. #1
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    Default Evohome with multiple BDR91's and underfloor heating

    Hi,

    I'm new to evohome, and after reading quite a lot on this topic, including this forum, there are a couple of things that i don't fully understand yet, so i'm looking for some advice.

    my current setup is:
    1 heat pump (on/off), controlled by 1 BDR91 and it's associated DT92E. (let's call it "master" BDR91/DT92E)
    The heatpump is connected to underfloorheating with 15 loops.
    Out of these 15 loops, 3 also have a BDR91 and associated DT92E (so 3 BDR91 and 3 DT92E additional) and each BRD91 (from these 3) controls an electric valve (on/off) on the underfloor heating loops.
    These 3 valves/bdr91's are only there to limit the heat in those 3 rooms (and not the other way around. so the heatpump will only turn on when the "master" DT92E is asking for heat, and not those 3 slave DT92E's)

    Since the heatpump need to be able to dissipate the heat when on, it will run water to the 15 loops all the time, except for those 3 rooms (where these valves can be shut off). So the result is that when the heatpump is on, it will run water to at least 12 loops.

    Now, enter evohome :-)
    I would like to have a similar setup, where
    - the "master dt92e" is replaced by the evohome and controls whether the heatpump is on/off
    - the 3 BDR91's and associated DT92E's are connected to the evohome (but again, only there to limit the heat, and not to turn on the master BDR91)
    - use the 1 spare DT92E as a dumb temperature sensor (that cannot call for the heatpump to start or stop)

    Can this be done?

    (i know that there exist an HCE80/HCC80R, but i'm not really prepared to remove the existing system)

    Thanks in advance!

  2. #2
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    Hi, I hope this helps you understand how evohome works. Firstly everything talks to the screen, nothing talks to each other. There are two separate areas in the set up, system devices that control your boiler or heat pump when there is a demand and can control heating and hot water zone valves ( not to be confused with UFH zones valves etc, they are zones). Then there is another area of set up called zones or zone options, these devices and thermostats are used to control the flow of heated water to each separate zone or room. None of these zones turn the boiler on directly.
    Every zone has an actuator and temperate sensor (thermostat DT92) there is no master thermostat !
    When any zone calls for heat the evohome screen sends a signal to one or all the system device relays (BDR91) to trigger the boiler.
    Can you list the zones you want and what type of heating they have (ie. UFH, radiator) and I will list what to bind to what.
    Hope this helps,

  3. #3
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    Hi,

    thank you for the explanation! really appreciate it.

    So attached you can see the current setup:
    20180924_090820.jpg

    where:
    - DT92e-1 (living room) controls the BDR91-1 (to switch the heatpump on/off). If the heatpump is switched "on", it provides warm water to all of the 15 underfloorheating loops of the house.
    - then there are 3 more sets of DT92E's and associated BDR91's with attached electric valves (on/off) to limit the heat in these 3 bedrooms. (but these 3 cannot switch on/off the heatpump)

    In order to make things a bit more energy efficient and easier to control, I bought an evohome to replace the DT92e-1 and use that as the thermostat in the livingroom.
    Basically, i want to have a similar setup as before, but integrated in 1 evohome screen.
    So that the evohome (living room) can switch the heatpump on/off when the temperature in the livingroom drops below the threshold, but that the 3 other bedroom DT92e's just control the BDR91's that are wired to the electric valves of the UFH. (so they are not allowed to turn on/off the heatpump, just the valves).
    And as a bonus, it would be great if i can use that spare DT92E-1 as an extra temperature sensor (that doesn't control anything, just displays on the evohome screen)

    Hope this helps?
    Thanks in advance!

  4. #4
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    Hi, sorry for the late reply, I have been busy installing evohome systems. What you have can easily be controlled by evohome. Can you check again that there is no electrical connection to the heat pump from the 3 circuits that are only controlling actuators please. If this is correct I will make you a list of things to bind and set up to make it all work on the evohome screen. Can you learn how to clear and bind both the DT92 & BDR91's please, you need to be sure you can do this for it work. Cheers.
    Also can you give me a simple sketch plan of the rooms, a plan of the house so I can see where everything is.
    Last edited by Mac4; 26th September 2018 at 10:12 AM. Reason: more info

  5. #5
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    Thanks!
    - only the BDR91 next to the heatpump is wired to the heatpump. the other 3 BDR91's are directly attached to a powersocket and to the thermal actuators
    - I can clear and bind DT92 and BDR91 (if someone on the forum is interested, https://ees-techlit.honeywell.com/em...-uk01r0317.pdf seems to cover it quite well, as well as youtube)
    - I'll attach the floorplan with the zones and calculations for the UFH
    UFH-groundlevel.jpg
    UFH-level1.jpg

  6. #6
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    Hi, first thing to do is a factory reset on the evohome screen and the BDR91 that controls the heat pump. Then in the installer menu, go to system devices and select boiler relay and clear and bind the BDR91, make sure no hot water is selected ( you didn't mention hot water but you can do that later)
    Then clear one of UFH zones BDR91 and DT92, go to add zone and select zone valve ( do not use the evohome screen as the thermostat if prompted ) - repeat this for each of your zones binding them as zone valves. You will have 4 x zones + the original one called living room, this zone will be using the evohome screen as the thermostat. Good luck, let me know how it goes.

    Hi, just to clarify that the living room zone also needs a BDR92 binding which controls it’s group UFH actuators ( this BDR91 must not switch the heat pump on, only actuators) the thermostat for this zone can be the evohome screen or a DT92. It’s probably easiest to delete the living room zone and create it again as you did on the other zones binding it as a zone valve.
    After you have done all the set up, when any individual zone calls for a heat demand it will turn on the heat pump via the boiler relay and its relay will open its actuators giving you 5 separate zones on one screen.
    NB: keep all the BD92’s at least 400mm away from metal pipes, cables and any other wireless device. Never fit two next to each other !
    Last edited by Mac4; 28th September 2018 at 07:31 AM. Reason: more details

  7. #7
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    Hi, (sorry about this) but I’m still having difficulties to fully understand. you mentioned "After you have done all the setup, when any individual zone calls for a heat demand it will turn on the heat pump via the boiler relay and its relay will open its actuators giving you 5 separate zones on one screen. "
    That's the thing, i don't want those zones turning on the heat pump. The only zone that should turn on the heat pump is the living room, where the evohome controller acts as the room thermostat. The other zones should only control the actuators (open/close), and not request for heat on the heat pump).

    Also, you mention "the living room zone also needs a BDR92 binding which controls it’s group UFH actuators" i don't have any electric zone valves for the living room.
    Basically, all the valves for all the water circuits (living room, bedrooms, kitchen,...) are always open by default, it's just on 3 specific water circuits, that there are 3 electric actuators that are connected to 3 separate BDR91's (just to limit warm water flowing through the circuit)

    Apologies for all my questions, I’m slowly getting the hang of it (with the key word being "slowly" ;-) )

  8. #8
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    Quote Originally Posted by bramvds View Post
    That's the thing, i don't want those zones turning on the heat pump. The only zone that should turn on the heat pump is the living room, where the evohome controller acts as the room thermostat. The other zones should only control the actuators (open/close), and not request for heat on the heat pump).
    Set them up as electric zones then. They'll open/close as required but won't call for heat.

  9. #9
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    The problem with trying to help out like this is I do not know how every thing it set up and wired up
    It is easily possible to control your home with evohome but it will take so many messages back and forward to make sure it is correct, then still not be 100%, sorry.

    You can contact me direct on 07970 035482 if it helps.

  10. #10
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    Quote Originally Posted by paulockenden View Post
    Set them up as electric zones then. They'll open/close as required but won't call for heat.
    Hi,

    Can anyone provide further information on how to 'Set them up as electric zones'

    I want to use a BDR91 to switch the pump on the UFH manifold, but don't want it to call for heat from the 'boiler' (or in my case thermal store)

    How do I bind the BDR91 to get this behaviour? The only option I see is Underfloor Heating, not Electric underfloor heating and I couldn't get it to bind to the BDR91 under the UFH option!?

    Any help appreciated.

    Regards,
    Scott.

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