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Thread: New evohome FW - update WiFi 02.00.17.00 and Application 02.00.17.03

  1. #151
    Automated Home Jr Member
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    I am puzzled as to how there can be a percentage showing for (BDR91 ) wireless relay box, would it not be the case that this is either on or off (100% or 0%).
    It is currently off (no green LED)but showing 56%

  2. #152
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    Quote Originally Posted by radar2016 View Post
    I am puzzled as to how there can be a percentage showing for (BDR91 ) wireless relay box, would it not be the case that this is either on or off (100% or 0%).
    It is currently off (no green LED)but showing 56%
    No. The controller sends the heat demand (together with the boiler cycling parameters) to the BDR91 and it is responsible for doing the TPI modulation itself.

  3. #153
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    Quote Originally Posted by mylesm View Post
    Thanks Rameses

    Heres my App Screen Attachment 1153

    And my Evo Screen Attachment 1154

    As you can see its on App but not on Evo any hints

    Thanks
    Mylesm
    Any update Why outside weather is showing on app but not on Evohome Screen

    Happy New Year
    Mylesm

  4. #154
    Automated Home Ninja Dan_Robinson's Avatar
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    Quote Originally Posted by radar2016 View Post
    I am puzzled as to how there can be a percentage showing for (BDR91 ) wireless relay box, would it not be the case that this is either on or off (100% or 0%).
    It is currently off (no green LED)but showing 56%
    BDR's are surprisingly clever.
    Kind Regards - Dan Robinson (Jennings Heating Ltd)

  5. #155
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    Has the app API been updated with the Heat Demand %?

  6. #156
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    Two weeks on, the updated firmware seems to be working well. The difference between the OATs on the App and the controller is slightly irritating, and I am not sure what value added there is in having this information on the controller (or the App for that matter). As hard as I try, I cannot see any correlation between the total percentage on the boiler and the sum of the individual zones. On the odd occasion, the zone percentages equal the boiler percentage; more often than not, they do not. As I post, I have also got one zone where the set and target temperatures are the same; the radiators have been stone cold for over an hour, and the zone is showing an 8% heating demand. This is often the case, and it is not just one single zone. Perhaps Honeywell could provide some clarity on what the percentages actually mean in layman's terms.

  7. #157
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    Quote Originally Posted by HenGus View Post
    Two weeks on, the updated firmware seems to be working well. The difference between the OATs on the App and the controller is slightly irritating, and I am not sure what value added there is in having this information on the controller (or the App for that matter).
    I like having the outside temperature reading but it does annoy me that it disagrees with the temperature reading in the app - I see the post from Andy earlier in the thread confirming that they use two different weather services, which whilst explaining the discrepancy doesn't really excuse it. After comparing over time the reading on the control panel, the iPhone app, weather pro (metogroup) and my own outdoor temperature sensor it seems that the service used by the controller is less accurate than the one used by the Honeywell iPhone app - sometimes by a few degrees.
    As hard as I try, I cannot see any correlation between the total percentage on the boiler and the sum of the individual zones. On the odd occasion, the zone percentages equal the boiler percentage; more often than not, they do not.
    I discussed this over in the following post:

    http://www.automatedhome.co.uk/vbull...ll=1#post35444

    The correlation seems pretty simple to me - the the total percentage heat demand is simply the maximum heat demand of any individual zones including hot water. Simple as that. Don't forget to check page 2 (and 3 if you have one) as not all the zones fit on the first page.

    As I post, I have also got one zone where the set and target temperatures are the same; the radiators have been stone cold for over an hour, and the zone is showing an 8% heating demand. This is often the case, and it is not just one single zone. Perhaps Honeywell could provide some clarity on what the percentages actually mean in layman's terms.
    Again, discussed in the above linked post.

    The heat demand is derived from the HR92 valve pin position percentage as shown in the graph in the linked post. The valve position has to be about 30% or more before any heat demand is generated.

    That heat demand of the zone with the highest heat demand then controls the duty cycle % of the BDR91, or the flow temperature for Opentherm. (Nobody has measured the relationship between heat demand and OpenTherm flow temperature yet - now that heat demand is visible are there any takers ?)

    Funnily enough I have the same problem as you in several zones, but even more severe, with zones showing heat demands as high as 25% while the radiator is stone cold, and although I was sort of aware that this was going on in a couple of zones the heat demand display has really brought to my attention just how bad it is and how many zones are doing it.

    I know exactly what is causing it in my case as well - sticky valve bodies which have been getting progressively worse over time as (presumably) the rubber seals in the valve go hard/sticky or the pin corrodes.

    A good example is the bathroom - I have kept an eye on the heat demand screen quite a bit since the update (I've actually just left it on that screen a lot of the time) and I noticed the bathroom was showing a 25% heat demand even though the radiator was stone cold. I checked the valve position (option 10) on the HR92 and sure enough it said about 65% (which correlates with a 25% heat demand if you refer to my graph) and yet no water was flowing through the radiator, and I know the boiler was running at the time for other zones.

    This is definitely a fault or incompatibility with the valve body as it should start flowing at about 30% indicated pin position not over 65%! I know its not an incompatibility per-se in this instance because these valve bodies (Peggler bulldog) all worked perfectly with the HR92's when new two years ago but over time one by one they have started to get sticky and have forced me to enable stroke 1 mode on some of them otherwise they won't open fully.

    If the valve won't start flowing until the pin position is a long way past 30% then you will indeed see heat demand with no water flowing through the valve... As a workaround until I can get rid of these valves and install some Valencia's I have found enabling stroke 1 re-calibrates the valve in such a way that this problem doesn't seem to happen. Unfortunately this does tend to cause more overshoots and supposedly reduces battery life, but without this setting on some of my radiators they will generate heat demand without allowing any water through the radiator...and also fail to heat up fully during high demand.

    Another thing that sticky valve bodies can cause is constant overshoots/oscillation in temperature and inability to keep a steady temperature. Over time the oscillations have got worse in many of my rooms, and again I put it down to sticky valve bodies. This is because ideally the valve body should start flowing at about 30% as it is opened and also stop flowing at about 30% as it is closed with little if any hysteresis.

    When they are sticky what you'll find is that it won't start flowing until the pin position reaches a much higher percentage - over 65% in the bathroom, but then won't close again until the percentage is way lower - I'm seeing some valves that won't stop flowing until under an indicated 20%. In those cases the room is over temperature by nearly a degree, the valve position is down to 20% or less (and 0% heat demand indicated) but the valve is still flowing water - which means if other zones are calling for heat the room will keep heating and go well past the set point before it finally shuts it right down.

    The stickiness adds loads of hysteresis to the control of the water flow through the radiator, and overshoots and oscillations are inevitable in that situation as the system simply can't control the flow of water through the radiator properly.

    In your case if you have a persistent problem with a zone calling for heat when it is not flowing you might want to try setting stroke to 1 - just change the setting to 1, remove the HR92, wind out the black wheel then refit it to force a full re-calibration and see if it helps.

    If not, you might be seeing problems with the valve bodies becoming sticky, although an 8% heat demand is nowhere near as bad as what I'm seeing.
    Last edited by DBMandrake; 2nd January 2018 at 02:07 PM.

  8. #158
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    All my TRV bodies were replaced with new Valencia bodies 9 months ago. This is what my readings are at the moment:


    Boiler Control Opentherm 42%

    Hall/Landing 42% (the 3 radiators are slightly undersized so this zone is always showing a heat requirement when it is close to the set temp)

    Study 14% (the rad is barely warm)

    Dining Room 2% (cold radiator)

    Bed 4 4% (cold radiator)

    Bed 5 12% (over an integral garage - warm radiator)

    Toilet 1% (cold radiator)

    I do not see how any of the above equates to a boiler control/opentherm demand of 42%: that said, I accept that your finding does confirm what I am seeing on the controller. What it doesn't explain is what is happening with the boiler which, in truth, is very little. The boiler pump is running for long periods with a calculated flow temperature of 20C. It will then burn for a few minutes until the flow temperature reaches a calculated flow temperature of 50C. During this time, the boiler demand % stays at 42%. It's been like that now for over 30 minutes. All zones are at (or above by 0.5C) their set temperatures.

    Edit: popped out for 20 mins:

    Boiler Control 42%

    Kitchen 14%

    Hall/Study 42%

    Dining Room 12%

    Bed 4 4%

    Bed 5 2%
    Last edited by HenGus; 2nd January 2018 at 03:06 PM.

  9. #159
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    In the above scenario surely the boiler demand is just the demand of the zone requiring the biggest demand. Iím not sure why there is a need or why we would expect to sum each zone demand. For me what is more interesting is the algorithm used by the bdr91 to fire the boiler based on the different demand inputs.

  10. #160
    Automated Home Legend paulockenden's Avatar
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    I agree with Simon that it's the max of the zones. But I also think there might be a very small amount of moving average smoothing involved too.

    There's one person here who could probably give us chapter and verse, rather than all this deduction and guesswork.

    P.

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