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Thread: Evohome new user

  1. #11
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    Came back from work to find the house toasty

    Yes, what you said about the hot water makes sense. Having had it for the day, I think the only issue I’m currently left with is that when the hot water goes on, it switches on the central heating valve as well. I assume this is due to binding both bdr91s in the Hot water configuration - hot water valve and heating valve. I’ll go back through the water configuration and try not to bind the heating valve but I’m not sure it’ll let me do just the one by backing out when it asks for the heating valve.

    Good tip on the hr92 temperature setting. Turning them down to 5 immediately cuts the boiler (if hot water is off!!) and turning them up to 25 puts it back on, so all working well.

    Actually, slight change of plan - I see on the System Summary screen I now have
    Boiler Control: Wireless Relay Box
    Stored Hot Water: 2 two or three port valves
    Living Room: Radiator Valve

    So I assume that means I have (again!) ended up with the boiler relay set up (oops) and I should go into System Devices and remove the Boiler Control binding?
    Last edited by Jemster; 11th December 2018 at 07:25 PM.

  2. #12
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    Quote Originally Posted by Jemster View Post
    Actually, slight change of plan - I see on the System Summary screen I now have
    Boiler Control: Wireless Relay Box
    Stored Hot Water: 2 two or three port valves
    Living Room: Radiator Valve

    So I assume that means I have (again!) ended up with the boiler relay set up (oops) and I should go into System Devices and remove the Boiler Control binding?
    Yes, you've somehow bound a boiler control relay when you shouldn't. This is why hot water is switching on the central heating zone valve as well. With your system you don't want a boiler control relay configured, it should say none for boiler control.

    I would do the following:

    Clear the bindings on both BDR91 (long press for >15 seconds) then go into System Devices and change both boiler control and stored hot water to none. This removes the binding at the controller end. Then go back into stored hot water and follow the binding process again, choosing "two 2 port or three port valves".

    You should be asked to bind the hot water sensor, hot water zone valve relay, and heating zone valve relay. You should not be prompted to bind a boiler relay.

    When you're finished stored hot water should be configured but boiler control should still say none.

    You'll need to re-enter your hot water schedule and hot water set point/differential as these will be erased when you set stored hot water to none.

  3. #13
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    I hate to say anything at this stage... but I think I've got it right now!

    And of course, it's simple. Well, probably. If what I've got is right!

    I'm trying to work out why so many hours have been spent getting it working and come down to a few things that held me and my plumber up (and these are just my new-user opinions obviously):

    Inconsistent naming is a headache for the inexperienced - boiler relay, boiler control, boiler actuator... all the same thing and we don't want none of that

    Seems illogical to be setting up the central heating valve controller under the hot water settings and left me thinking had I left something out but I think I ended up re-binding the heating valve as the boiler control when I went through the Zone Configuration on the Setup Wizard.

    Not knowing how to test if I had got it right and just having to wait for the Controller to get around to switching things - the non-transparent nature of the switching made me think I'd got something wrong. What's on the screen does not reflect directly with what's happening on the BDR91's, e.g. Hot Water being red and saying it's heating, yet it's not because it's within 10 degrees of the set point. Same applies on that summary screen - it shows demand but this doesn't necessarily equate to what relays are currently on or off. Surely this could be more "user friendly", after all, the controller MUST know what state the relays are currently in, how could it not. Just add a simple dot icon changing colour to match the current state (and maybe the pending state on the next refresh cycle) for each bound BDR91 would at least allow the user to confirm the bindings and communication are correct.

    Oh yeah! And that crazy RF test that gives options to test the hot water relay and heating relay and yet no matter which one you pick, both relays flash... This does not help when trying to work out if there is a binding problem.

    DBMandrake, thank you so much for the help. In particular the tip that adjusting an HR92 had an immediate effect on demand as opposed to overriding on the Controller has allowed me to check out that I had the heating valve set up correctly. And the 10 degree thing (with the Controller constantly resetting to 50 degree set point for hot water every time I re-bound!) caused some confusion.

    Tonight will be spent setting up the additional 8 zones with 12 more HR92s to go on. Fingers crossed this time it will go smoothly.

  4. #14
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    Quote Originally Posted by Jemster View Post
    I'm trying to work out why so many hours have been spent getting it working and come down to a few things that held me and my plumber up (and these are just my new-user opinions obviously):

    Inconsistent naming is a headache for the inexperienced - boiler relay, boiler control, boiler actuator... all the same thing and we don't want none of that

    Seems illogical to be setting up the central heating valve controller under the hot water settings and left me thinking had I left something out but I think I ended up re-binding the heating valve as the boiler control when I went through the Zone Configuration on the Setup Wizard.
    Yes the documentation is lacking. Although Honeywell sell the kit to end users the documentation is really written with installers in mind, although there is free online "training" available that covers a bit more about planning an installation. Why that's not just in the documentation I'm not sure.
    Not knowing how to test if I had got it right and just having to wait for the Controller to get around to switching things - the non-transparent nature of the switching made me think I'd got something wrong. What's on the screen does not reflect directly with what's happening on the BDR91's, e.g. Hot Water being red and saying it's heating, yet it's not because it's within 10 degrees of the set point.
    I guess you're expecting the hot water symbol to work like the light on an oven that goes out when up to temperature ? It just doesn't work that way though, it only represents whether it is scheduled to be on or off. Makes sense when you're aware of that fact. Red means the hot water is either up to temperature or is currently trying to heat up to temperature. And given that there is a temperature reading as well I don't have too much problem with this presentation. We have a switch for our immerser element that has a red light inside it, it glows read the whole time the cylinder is turned on even if the thermostat is currently cut out due to it being up to temperature, so much the same.
    Same applies on that summary screen - it shows demand but this doesn't necessarily equate to what relays are currently on or off. Surely this could be more "user friendly", after all, the controller MUST know what state the relays are currently in, how could it not.
    Aha - it's not quite as simple as that behind the scenes though. The controller doesn't actually turn the heating BDR91 on and off explicitly every time you see it go on and off. It semi-periodically (every 20 minutes, or when there is a change in demand) sends it a heat demand percentage from 0 to 100%. The BDR91 then performs TPI (time proportional integral) switching all by itself based on that heat demand and based on the TPI cycle time configured.

    Example:

    The default cycle time is 6 cycles per hour, in other words a 10 minute long cycle. If the heat demand was 40% then the controller says to the BDR91 "40% heat demand please and 6 cycles per hour". The BDR91 will then cycle on for 4 minutes and off for 6 minutes, then on for 4 minutes, then off for 6 minutes and so on, until the heat demand changes.

    This whole time the heat demand reported will be 40% but at any given moment the BDR91 might be on or it might be off depending on where in the cycle it is. But the percentage reported on the controller is the percentage of time in each cycle that the BDR91 will be on.

    Hot water works slightly differently - the controller just calls for either 100% or 0% heat demand with nothing in between, so hot water only has two directly controlled states of on or off.
    Just add a simple dot icon changing colour to match the current state (and maybe the pending state on the next refresh cycle) for each bound BDR91 would at least allow the user to confirm the bindings and communication are correct.
    I don't think the RF protocol supports querying the current state of the relay. One reason for this is that it's actually possible to bind more than one device to a BDR91. For example if you had two Evohome controllers in a really large house I think they can both be bound to the same BDR91 - which will then operate based on whichever system is calling for the highest heat demand.
    Oh yeah! And that crazy RF test that gives options to test the hot water relay and heating relay and yet no matter which one you pick, both relays flash... This does not help when trying to work out if there is a binding problem.
    Yes I agree about this - I'm also puzzled why doing a signal test for only hot water or only heating relays causes the light to flash on both. Not sure if it's a bug or whether it's just improperly documented! Mine has always worked this way.
    Tonight will be spent setting up the additional 8 zones with 12 more HR92s to go on. Fingers crossed this time it will go smoothly.
    I think you'll be fine now. Best of luck.
    Last edited by DBMandrake; 13th December 2018 at 02:49 PM.

  5. #15
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    Quote Originally Posted by DBMandrake View Post
    Yes the documentation is lacking. Although Honeywell sell the kit to end users the documentation is really written with installers in mind, although there is free online "training" available that covers a bit more about planning an installation. Why that's not just in the documentation I'm not sure.
    I'd been through all the training videos, and although they were helpful, they didn't really highlight things like the boiler relay (the only places I'd found references to that are from Richard on the evohomestore website and from what you've said).

    Nor did they say "don't panic when things aren't working the way you think they should be"

    Quote Originally Posted by DBMandrake View Post
    Aha - it's not quite as simple as that behind the scenes though. The controller doesn't actually turn the heating BDR91 on and off explicitly every time you see it go on and off. It semi-periodically (every 20 minutes, or when there is a change in demand) sends it a heat demand percentage from 0 to 100%. The BDR91 then performs TPI (time proportional integral) switching all by itself based on that heat demand and based on the TPI cycle time configured.

    Example:

    The default cycle time is 6 cycles per hour, in other words a 10 minute long cycle. If the heat demand was 40% then the controller says to the BDR91 "40% heat demand please and 6 cycles per hour". The BDR91 will then cycle on for 4 minutes and off for 6 minutes, then on for 4 minutes, then off for 6 minutes and so on, until the heat demand changes.

    This whole time the heat demand reported will be 40% but at any given moment the BDR91 might be on or it might be off depending on where in the cycle it is. But the percentage reported on the controller is the percentage of time in each cycle that the BDR91 will be on.

    Hot water works slightly differently - the controller just calls for either 100% or 0% heat demand with nothing in between, so hot water only has two directly controlled states of on or off.

    I don't think the RF protocol supports querying the current state of the relay. One reason for this is that it's actually possible to bind more than one device to a BDR91. For example if you had two Evohome controllers in a really large house I think they can both be bound to the same BDR91 - which will then operate based on whichever system is calling for the highest heat demand.
    Ahhh gotcha! That's pretty darned clever. So the yellow light on the BDR91 goes on and off independently of the Controller. Now I understand. I thought the Controller was responsible for each relay on/off operation.

    Quote Originally Posted by DBMandrake View Post
    Yes I agree about this - I'm also puzzled why doing a signal test for only hot water or only heating relays causes the light to flash on both. Not sure if it's a bug or whether it's just improperly documented! Mine has always worked this way.

    I think you'll be fine now. Best of luck.
    I was fine I now have 9 zones set up and mostly everything going on and off accordingly. There's some weird stuff going on in multi-radiator rooms when setting up the zones. Sometimes I added a zone, it had me bind the first radiator valve, then explicitly asked me if there were more to bind. Then when I'd got on to the 3rd or 4th zone, it stopped doing this and had me bind the first radiator valve followed by a screen to bind additional actuators with the green bind button - it seems to have done the same thing, but really strange as I was going through the same process over and over again. Must be a little bug as I think everything is now working!

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