Page 5 of 27 FirstFirst 1234567891015 ... LastLast
Results 41 to 50 of 262

Thread: Help with Evohome / Opentherm / Intergas

  1. #41
    Automated Home Legend paulockenden's Avatar
    Join Date
    Apr 2015
    Location
    South Coast
    Posts
    1,602

    Default

    I don't understand this single/multiple zone thing with Intergas. The boiler doesn't KNOW how many zones there are. It's simply getting an aggregated heat demand from the controller.

    Some have speculated that with multiple zones there might be more data coming in for the boiler to deal with, but again, I don't get that. Evohome is sending an aggregated value with is for the whole house. You could easily get MORE variation from a single zone control if it's sited next to a doorway, for example.

    And even if there IS more data even the most badly designed logic board should be able to cope. Easily.

    There's something really strange about this excuse that it can't cope with multiple zones.

  2. #42
    Automated Home Legend
    Join Date
    May 2014
    Posts
    988

    Default

    Quote Originally Posted by blowlamp View Post
    How many boilers are properly compatible with Evohome when used in its OpenTherm configuration?
    From what I've seen here, none are truly working correctly and that includes Atag as well as Ideal, Vaillant, Intergas & Veissmann.

    .
    I would disagree with the assertion that the Atag IS/IC range isn’t compatible with Evohome/Opentherm. I have seen the boiler flow temperature as low as 50c with CH on. It just takes time to get there and I believe that the ‘fault’ was more to do with my zone timings/temps. Given that the boiler was only installed in April, the weather conditions have never needed full time boiler operation. I know that others have experience of Opentherm operation with other boilers over a longer period and may be able to comment further.

    This is what was said when I was last in contact with an Intergas installer:

    Quote: The problem is that the boiler or Evohome (no one really knows which at the moment) doesn't cope with modulating the setpoint with multiple zones.

    My theory is that there is too much data and the boiler PCB can't interact quickly enough with the OpenTherm bridge so it drops its knickers and runs at whatever the maximum setting is. Unquote


    Read more: https://www.diynot.com/diy/threads/i...#ixzz4lh9XvW9v
    Last edited by HenGus; 2nd July 2017 at 07:08 PM.

  3. #43
    Automated Home Sr Member
    Join Date
    Apr 2017
    Posts
    84

    Default

    I agree with paulockenden about the boiler being oblivious to the number of zones - in fact I agree with his whole post. His thoughts were my thoughts when I mused about how Intergas/Evohome/OpenTherm would function with a single zone setup. My thinking being that if modulation were to happen under a single zone, then that might point to Evohome being the culprit.

    I'm just trying to bring a perspective outside of Evohome when a boiler is hooked-up to an Opentherm controller. My experience is that Intergas/OpenTherm, along with a controller from a competitor boiler manufacturer is working and has been working for nearly two years and in a 'textbook' fashion.

    With regard to boiler/Evohome/OpenTherm compatability, my point is that Evohome seems to be 'missing the mark' in some way, with just about all the boilers the average person can lay his hands on

    Unless your radiators are quite moderately specified then 50c flow temperatures (at what set/outside temperature?) in springtime should, in my experience, probably be lower under OpenTherm control and it shouldn't take long for your boiler to reach the condensing phase of its operation and remain there. I think the Intergas can control flow temperatures down into the mid twenties under OpenTherm.



    Martin.

  4. #44
    Automated Home Legend
    Join Date
    Jul 2014
    Posts
    1,003

    Default

    I too have thought that people have confused Evohome multiple zones and the Intergas boiler max limit issue as being linked. The only link I can see is that in a multi zone system you may have many zones outside of the proportional band at different times. We know that even a single zone outside will make the Evohome OT bridge run the boiler at max. Now layer on that the fact that Intergas max means boiler physical max and then suddenly you have a boiler that is running too hot for too long. That doesn't happen when using a single zone OT controller.

  5. #45
    Automated Home Legend
    Join Date
    May 2014
    Posts
    988

    Default

    Quote Originally Posted by bruce_miranda View Post
    I too have thought that people have confused Evohome multiple zones and the Intergas boiler max limit issue as being linked. The only link I can see is that in a multi zone system you may have many zones outside of the proportional band at different times. We know that even a single zone outside will make the Evohome OT bridge run the boiler at max. Now layer on that the fact that Intergas max means boiler physical max and then suddenly you have a boiler that is running too hot for too long. That doesn't happen when using a single zone OT controller.
    This is why my installer suggested that maximum efficiency can be achieved by restricting the number of changes to set temps in zones; ie, get them all up to temperature and leaving them there and by avoiding cold spots in adjacent rooms.

    It is interesting that Honeywell has been totally silent on this issue to date.

  6. #46
    Automated Home Legend
    Join Date
    Sep 2014
    Location
    Scotland
    Posts
    1,844

    Default

    Quote Originally Posted by paulockenden View Post
    I don't understand this single/multiple zone thing with Intergas. The boiler doesn't KNOW how many zones there are. It's simply getting an aggregated heat demand from the controller.
    To put it politely, the "not compatible with multiple zones" is bull dust...

    There is nothing in the OpenTherm spec to even make the boiler aware that a system might be zoned. What does zoned mean anyway ? Does a system with manual TRV's count as a "zoned" system ? Of course. Every zone can independently control the flow of water through it's radiator(s).

    How many heat demands are sent to an OpenTherm boiler if you have a traditional single-zone thermostat ? One.

    How many heat demands are sent to an OpenTherm boiler if you have a multi-zone system like Evohome, where individual zones can call for heat, and the demand is aggregated ? Still One.

    The spec doesn't allow for communication of multiple zone heat demands, and even if it did, what would the boiler do with that information ? A boiler can only output one flow temperature on the heating circuit at a time.

    In short, it's a nonsense excuse from Intergas for a problem that can't exist. Clearly there is some sort of issue with their OpenTherm support but it's nothing to do with not being able to handle a multi-zone system like Evohome.

    bruce_miranda's suggestion may be closest to the truth - if Intergas is one of the boilers that can't limit the maximum flow temperature in OpenTherm mode and you have a complex schedule where there are frequently rooms increasing their set points it could well lead to a situation where the flow temperature is very high a lot of the time, where it wouldn't be on a single zone system, making it semi-useless.

    However if this is the real issue, Intergas are certainly not alone, and it's getting to the point where Honeywell need to act and provide a maximum OpenTherm flow temperature setting in the Evotouch software. (Where you would expose it in the user interface I'm not sure though, as it would need to be a bit more prominent than being hidden in the installer menu, as mere mortals would need to be able to adjust it as the seasons changed...)

    Has anyone here actually used Intergas OpenTherm with Evohome and if so what are the symptoms you notice (if any) ?
    Last edited by DBMandrake; 3rd July 2017 at 12:09 AM.

  7. #47
    Automated Home Sr Member
    Join Date
    Apr 2017
    Posts
    84

    Default

    When an OpenTherm controller is connected to a (in this case Intergas) boiler, the onboard controller surrenders that control and becomes its slave in all but the most fundamental ways.

    As the relationship is now one of master & slave, then amongst other things it becomes the task of the offboard controller to set and maintain flow temperature (including max), so expecting the onboard controller to limit the excesses or inadequacies of the offboard controller isn't how OpenTherm is designed to work.

    As far as I am aware, Intergas have never implied this fault lies with their boiler, let alone issue an excuse for it.
    Also, Intergas are based in the Netherlands where OpenTherm is mandatory, so it'd be fair to assume they have a decent understanding of what's required for it to work.

    Please take a look at the manual at this link to see the functions of a dedicated OpenTherm control.

    https://www.remeha.co.uk/-/media/The...ice-manual.pdf




    Martin.
    Last edited by blowlamp; 3rd July 2017 at 02:17 AM.

  8. #48
    Automated Home Legend
    Join Date
    May 2014
    Posts
    988

    Default

    Quote Originally Posted by DBMandrake View Post
    To put it politely, the "not compatible with multiple zones" is bull dust...

    There is nothing in the OpenTherm spec to even make the boiler aware that a system might be zoned. What does zoned mean anyway ? Does a system with manual TRV's count as a "zoned" system ? Of course. Every zone can independently control the flow of water through it's radiator(s).

    How many heat demands are sent to an OpenTherm boiler if you have a traditional single-zone thermostat ? One.

    How many heat demands are sent to an OpenTherm boiler if you have a multi-zone system like Evohome, where individual zones can call for heat, and the demand is aggregated ? Still One.

    The spec doesn't allow for communication of multiple zone heat demands, and even if it did, what would the boiler do with that information ? A boiler can only output one flow temperature on the heating circuit at a time.

    In short, it's a nonsense excuse from Intergas for a problem that can't exist. Clearly there is some sort of issue with their OpenTherm support but it's nothing to do with not being able to handle a multi-zone system like Evohome.

    bruce_miranda's suggestion may be closest to the truth - if Intergas is one of the boilers that can't limit the maximum flow temperature in OpenTherm mode and you have a complex schedule where there are frequently rooms increasing their set points it could well lead to a situation where the flow temperature is very high a lot of the time, where it wouldn't be on a single zone system, making it semi-useless.

    However if this is the real issue, Intergas are certainly not alone, and it's getting to the point where Honeywell need to act and provide a maximum OpenTherm flow temperature setting in the Evotouch software. (Where you would expose it in the user interface I'm not sure though, as it would need to be a bit more prominent than being hidden in the installer menu, as mere mortals would need to be able to adjust it as the seasons changed...)

    Has anyone here actually used Intergas OpenTherm with Evohome and if so what are the symptoms you notice (if any) ?
    This guy has and issues are also reported on Richard's forum:

    https://www.diynot.com/diy/threads/i...#ixzz4lh9XvW9v

  9. #49
    Automated Home Legend
    Join Date
    Sep 2014
    Location
    Scotland
    Posts
    1,844

    Default

    Quote Originally Posted by HenGus View Post
    This guy has and issues are also reported on Richard's forum:

    https://www.diynot.com/diy/threads/i...#ixzz4lh9XvW9v
    Yep,

    We've all seen that thread from October last year before in previous discussions - but it doesn't go much beyond speculation. The poster (whoever they are) is just relaying Intergas's claim that the problem is due to not modulating with multiple zones, but offers no technical details to back up this claim.

    They then go on to speculate that there is "too much data" coming from the OpenTherm bridge, but that is pure unsubstantiated speculation and to be honest, as someone who works in computers and has done a little bit of embedded development, I don't buy this argument for a second.

    In short, we really don't know what the issue is, but I cannot see how it can be related to having multiple zones. It just seems like another case of a poor OpenTherm implementation.

  10. #50
    Automated Home Legend
    Join Date
    Sep 2014
    Location
    Scotland
    Posts
    1,844

    Default

    Quote Originally Posted by blowlamp View Post
    When an OpenTherm controller is connected to a (in this case Intergas) boiler, the onboard controller surrenders that control and becomes its slave in all but the most fundamental ways.
    And being able to limit the maximum flow temperature is a pretty fundamental thing, is it not ?
    As the relationship is now one of master & slave, then amongst other things it becomes the task of the offboard controller to set and maintain flow temperature (including max), so expecting the onboard controller to limit the excesses or inadequacies of the offboard controller isn't how OpenTherm is designed to work.
    So you think it's OK for a boiler to completely surrender control of the flow temperature to an OpenTherm master with no checks or balances or even a maximum limit ? So if the controller asks for 100 degrees the boiler should just do it even if it overheats ?

    Clearly different boilers are going to have different maximum flow temperatures that they can support, so they should place a sensible limit on the maximum that they will accept, even if only for their own protection. How is the controller supposed to know what is best for a given boiler ? Just because the OpenTherm master is nominally in charge doesn't mean it should have free reign.

    Perhaps by disabling local limits when under OpenTherm control the boiler is still following the letter of the protocol spec, but that doesn't mean it is following the spirit of the spec. Sometimes sanity has to intervene. The fact that some boilers do let you limit the maximum flow temperature under user control even when being controller by an OpenTherm master shows that it can be done.

    I suspect this is just a case of yet another not quite sufficiently defined protocol that leaves too much up to the implementers interpretation, and therefore interoperability issues arise. The frustrating thing is that neither party seems to want to take a step to improve the functionality of their device to be more compatible with the other, and instead seem to want to take up a "not our problem - we're following the spec" stance.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •