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Thread: Evohome and Zone Valves

  1. #11
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    Quote Originally Posted by Little Tinker View Post
    Your valves probably have 22mm pipework, and those are 15mm which will constrict flow quite a bit.
    Thanks i considered that but 2 of my Zone valves at present only have 15mm as they are only feeding a big Living room and a Kitchen Extension the third one is bedrooms its 22mm

    But replacing the present valves with Inline HR92s seems like a possible and would mean those zones would be completely integrated into EVO

  2. #12
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    Depending how inventive you want to be you could replace just the two on the 15mm legs, and wire the remaining zone valve in parallel with boiler. It then opens whenever any of the system wants heat, but the various HR91 will ensure heat only reaches where it is needed. Or with pump if that is accessible and you have pump overun.

    EDIT: Just realised you probably aren't putting heads on the bedroom rads which undermines the design. I'll leave it there anyway.
    Last edited by Little Tinker; 26th November 2016 at 03:13 PM.

  3. #13
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    Quote Originally Posted by Little Tinker View Post
    Depending how inventive you want to be you could replace just the two on the 15mm legs, and wire the remaining zone valve in parallel with boiler. It then opens whenever any of the system wants heat, but the various HR91 will ensure heat only reaches where it is needed. Or with pump if that is accessible and you have pump overun.

    EDIT: Just realised you probably aren't putting heads on the bedroom rads which undermines the design. I'll leave it there anyway.
    Yes I was thinking maybe two inline TRVs with HR92 Heads to replace the 2 15mm Zone valves existing and use two Honeywell Y87RF stats as sensors for each Zone that should take care of them

    The other Zone I could leave the existing Zone Valve and set it up as a Zone Valve zone in Evo and use a Honeywell Y87RF again as the Sensor for that Zone but not use end limits to trigger Boiler instead use a BDR91 as a Boiler Demand Relay to switch boiler which would give better Boiler control

    thanks again

  4. #14
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    Quote Originally Posted by DBMandrake View Post
    It's possible you might need a 4th BDR91 to control the boiler directly instead of using the orange wires from the zone valves as I'm not certain whether you can bind zone valve relays to the individual zones and yet have no overall boiler relay configured. Even if it does let you I'm also not sure whether this would allow good TPI control of the boiler when it will be doing TPI on each individual zone valve and all of them will be able to call for heat from the boiler. This might result in the boiler running more frequently than is necessary but its hard to be sure.

    You'd need to try it and see, and allow for the possibility that you might need a 4th BDR91 if it doesn't work out with three. If you did need the separate boiler control BDR91 you would just disconnect the orange wires from your zone valves that currently power the boiler and power the boiler directly from the extra BDR91 and add it as "boiler control" in the configuration.
    That's exactly the suggestion I have been given by a Evohome Connected Specialist. 4th BDR91 required as the boiler relay, with the orange wires disconnected for the 2 motorised valves (in my case, central heating + underfloor heating).

    I have 3 motorised valves, one for HW, one for central heating (CH) and one for underfloor heating (UFH) - my original installer installed three BDR91s to power those three valves independently, all of them in turn would fire the boiler up.

    When my UFH Zone asked for heat, it would open up the UFH valve + fire up boiler, but then it would also signal the CH BDR91 to open up the CH valve too.

    I had the same issue too when I first installed the Evohome HW kit - it would open the HW valve + fire up boiler, but the CH BDR91 would also be called and open up the CH valve - till I eventually sussed out that I needed to unbind the BDR91 relay that came with the Evohome connected pack, then rebind the HW kit as a "2 Two Port or Three Port Valves", which then allowed me to bind the 2 BDR91s correctly.

    However, I could not figure out how I could do that for my UFH zone valve till I contacted specialist.

  5. #15
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    Quote Originally Posted by ojock View Post
    That's exactly the suggestion I have been given by a Evohome Connected Specialist. 4th BDR91 required as the boiler relay, with the orange wires disconnected for the 2 motorised valves (in my case, central heating + underfloor heating).

    I have 3 motorised valves, one for HW, one for central heating (CH) and one for underfloor heating (UFH) - my original installer installed three BDR91s to power those three valves independently, all of them in turn would fire the boiler up.

    When my UFH Zone asked for heat, it would open up the UFH valve + fire up boiler, but then it would also signal the CH BDR91 to open up the CH valve too.

    I had the same issue too when I first installed the Evohome HW kit - it would open the HW valve + fire up boiler, but the CH BDR91 would also be called and open up the CH valve - till I eventually sussed out that I needed to unbind the BDR91 relay that came with the Evohome connected pack, then rebind the HW kit as a "2 Two Port or Three Port Valves", which then allowed me to bind the 2 BDR91s correctly.

    However, I could not figure out how I could do that for my UFH zone valve till I contacted specialist.
    If you've configured your UFH as just an additional zone using a BDR91 adding a boiler relay won't solve your problem of the CH BDR91 coming on when your UFH calls for heat. You need to change your UFH zone to an Electric UFH zone (On the new firmware update) and this will prevent the BDR91 on the CH from coming on and if you had a boiler relay prevent this from firing. At this point you'd just use the orange wire from the zone valve to fire the boiler for the UFH.

  6. #16
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    Quote Originally Posted by mtmcgavock View Post
    If you've configured your UFH as just an additional zone using a BDR91 adding a boiler relay won't solve your problem of the CH BDR91 coming on when your UFH calls for heat. You need to change your UFH zone to an Electric UFH zone (On the new firmware update) and this will prevent the BDR91 on the CH from coming on and if you had a boiler relay prevent this from firing. At this point you'd just use the orange wire from the zone valve to fire the boiler for the UFH.
    Amazing - just tried the ELECTRIC HEAT and it worked! Thank you so much.

    I bought a Evohome Connected Pack which included a BDR91 that was pre-bound as a boiler relay. However, when I then introduced the HW Kit, I had to unbind that relay, setup the Stored HW config as "2 Two Port or Three Port Valves", bind a new HW BDR91 relay (that came with the HW kit), then re-bind the relay (the one that came with the Connected pack) as a heating relay. This was done because I found that when I originally setup the HW as a "HW ONLY VALVE", when HW was calling for heat, it would also call the boiler relay which would then opened up the CH valve, changing to "2 Two Port or Three Port Valves" fixed the issue.

    So basically, I don't have a boiler relay as such since I added the HW kit.

    Now that I have it working as I think it should, it's great, but I'm wondering if "tricking" Evohome into thinking the UFH is Electric, when in fact it opens a motorised valve and fires up the boiler is somehow sub-optimal? Am I doing this because my design/setup is not how Evohome supposed to work?

    I thought I had simple requirements;
    1) Hot Water
    2) Underfloor heating (UFH) as a separate zone
    3) Central heating (CH) to all others controlled by HR92s

    I got the HW kit working correctly with the CH, I just couldn't figure out how to isolate the UFH so that it comes on without also turning on the CH. (my HW was causing the same issue, until I selected "2 Two Port or Three Port Valves", but I couldn't find an option like that for my UFH).

  7. #17
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    Quote Originally Posted by ojock View Post
    Amazing - just tried the ELECTRIC HEAT and it worked! Thank you so much.

    I bought a Evohome Connected Pack which included a BDR91 that was pre-bound as a boiler relay. However, when I then introduced the HW Kit, I had to unbind that relay, setup the Stored HW config as "2 Two Port or Three Port Valves", bind a new HW BDR91 relay (that came with the HW kit), then re-bind the relay (the one that came with the Connected pack) as a heating relay. This was done because I found that when I originally setup the HW as a "HW ONLY VALVE", when HW was calling for heat, it would also call the boiler relay which would then opened up the CH valve, changing to "2 Two Port or Three Port Valves" fixed the issue.

    So basically, I don't have a boiler relay as such since I added the HW kit.

    Now that I have it working as I think it should, it's great, but I'm wondering if "tricking" Evohome into thinking the UFH is Electric, when in fact it opens a motorised valve and fires up the boiler is somehow sub-optimal? Am I doing this because my design/setup is not how Evohome supposed to work?

    I thought I had simple requirements;
    1) Hot Water
    2) Underfloor heating (UFH) as a separate zone
    3) Central heating (CH) to all others controlled by HR92s

    I got the HW kit working correctly with the CH, I just couldn't figure out how to isolate the UFH so that it comes on without also turning on the CH. (my HW was causing the same issue, until I selected "2 Two Port or Three Port Valves", but I couldn't find an option like that for my UFH).
    No on Electric UFH heating it does TPI exactly the same as a normal zone valve but just doesn't close the boiler/CH relay. You aren't losing any performance.

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