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Thread: Evo Home Multi-Room Zones and BDR Demand

  1. #1
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    Default Evo Home Multi-Room Zones and BDR Demand

    We have a fairly large open-plan section of the house (6 radiators - 4 HR91, 2 HR92), and have also effectively run out of zones.

    Consequently, this section is configured as a single zone. It's been configured as a multi-room zone, to give the radiators a measure of autonomy, and also allows the radiators controlled by the HR92 to be locally tweaked.

    By & large this seems to work fine.

    However the demand sent to the BDR91 seems 'flawed'.

    If the zone, overall, is up to temperature, the valves are shut, and there's no demand to the BDR. Fine.

    However, if one HR92 is then tweaked up, that valve opens (you can hear it); but no demand is sent to the BDR. So that radiator doesn't get the hot water it requires. [Unless some other zone has set a demand.]

    This isn't what I'd expect, and seems like incorrect behaviour.

    I would have expected that any radiator valve can set the demand (or at least influence it).

    It would appear that only the representative sensor for the zone can set the demand. [?] If so, this doesn't work well for a multi-room zone.

    Or I'm missing something...

  2. #2
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    When you open up the HR valve, have you checked the System Summary page to see if that zone's Heat Demand has actually changed or not?

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    Quote Originally Posted by bruce_miranda View Post
    When you open up the HR valve, have you checked the System Summary page to see if that zone's Heat Demand has actually changed or not?
    Yes. That page is how I can tell there's no demand via the BDR91. [The indicator on the BDR91 shows the state of the relay, which is subtly different.]

    The Heat Demand shown in the summary page is another interesting point with respect to Multi-Room Zones. It's not clear what it's actually showing, when the demand can be different from the various HRs.

    [It's also not clear what the % number shown for the zone is. Valve position ? Heat Demand ?]

  4. #4
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    The System Summary page shows you the aggregated (or typically highest) Heat demand for a zone. And then the top line is against aggregating all Zone into a single boiler relay Heat Demand.
    Valve position can only be read on an HR92. I'm guessing you don't have a way to capture the actual RF traffic to see if the HRxx is actually requesting a Heat Demand, because it sounds like not.
    What is your Load Scaling set to?

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    Quote Originally Posted by bruce_miranda View Post
    The System Summary page shows you the aggregated (or typically highest) Heat demand for a zone. And then the top line is against aggregating all Zone into a single boiler relay Heat Demand.
    Valve position can only be read on an HR92.
    So the summary page is showing the valve's heat demand, rather than position; and the only way of seeing the valve position is via the menu on the HR92 ?


    I'm guessing you don't have a way to capture the actual RF traffic to see if the HRxx is actually requesting a Heat Demand, because it sounds like not.
    No RF tools. Are these affordable and/or worthwhile ?


    What is your Load Scaling set to?
    "Disabled" as I recall.

    That maybe leads to another issue, in that our configuration is currently changing a bit; and I do wonder if the 'fuzzy' 'learning' features can learn things that no longer apply, and whether that learning can be reset.

  6. #6
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    The summary page is showing the Zone's Heat Demand and the System's Heat Demand. Only the HR92 is capable of showing the valve position. And Simon produced an interesting analysis of how those two correlate and they are not linear at all. Our very own Peter produces an affordable RF device that is supported by almost all the known software out there. I.e. you have come to the right place :-) We are often telling Resideo what is wrong with their systems and how to fix them.
    Check your Load Scaling again because it was turned on by default in the last firmware update and that too causes issues with single zone heat demand.

  7. #7
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    Quote Originally Posted by bruce_miranda View Post
    The summary page is showing the Zone's Heat Demand and the System's Heat Demand. Only the HR92 is capable of showing the valve position.

    And Simon produced an interesting analysis of how those two correlate and they are not linear at all.
    Cool.

    Our very own Peter produces an affordable RF device that is supported by almost all the known software out there. I.e. you have come to the right place :-)
    Ok, that might be interesting...

    We are often telling Resideo what is wrong with their systems and how to fix them.
    ..but *do* they fix them..? The updates seem to be infrequent.

    Check your Load Scaling again because it was turned on by default in the last firmware update and that too causes issues with single zone heat demand.
    I'll keep an eye on that.

    We're currently in the slightly strange situation where the BDR91 isn't bound or controlling the boiler demand. [There's a horrible kludge doing the boiler demand.] I'd bound it to check it behaved, before getting the boiler tech to connect it to the boiler; which is how come I observed the behaviour. It will be rebound when that's done.

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    Yes Resideo do fix bugs, but in their time, not yours

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    If an HR92 is not generating any heat demand, reboot it by removing and reinstalling the batteries.

    It's an occasional glitch in the firmware of the HR92, I've seen it maybe half a dozen times in 5 years - the symptoms are that it seems to work fine in all other regards (opens/closes the valve, reports temperature readings and responds to set point changes) but refuses to send a heat demand.

    This glitch is often hard to notice as heat demand from other zones will fire the boiler in most cases disgusing the problem however if the radiator with the misbehaving HR92 is the only one trying to call for heat you'll notice it. (Or if you look closely in the heat demand page)

  10. #10
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    Come to think of it, I have seen this bug in an HR80 too.

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