Evohome woes

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  • G4RHL
    Automated Home Legend
    • Jan 2015
    • 1580

    #16
    Originally posted by killa47 View Post

    Am I mad or are other users doing likewise.

    Ian K.
    Far from mad but sane! I have left optimisation running but not convinced. Certainly not Optimisation On for if you want your house to be a certain temperature at 07:00 then you set the time for that to occur. In my case it would be about 20 minutes before the set time, optimisation starts nearly 60 minutes before. Optimisation Off though makes some sense but I have found rooms get cold quickly and you end up putting the heat back on. I don't mind the, cooling down 20 or 15 minutes before off time but 60 minutes before is too much.

    Yes we all play and look at the numbers at first but then realise that it is best left alone, we find the temperature that is comfortable and make minor adjustments only when needed. The at TRV temperature we soon learn is often not realistic but we fine tune to overcome that.

    We are told 2014 was a warmer year than 2015 with the latter being overall an average year. On this basis my gas comsumption in 2015 should have been more than in 2014 but it was a chunk less and indeed in 2014 I was way for 6 weeks in the late Autumn. What have I done that may have contributed to that? Installed Evohome in December 2014!

    Comment

    • killa47
      Automated Home Guru
      • Jan 2016
      • 123

      #17
      Great feedback Paul and G4RHL.

      When I set the initial time and temp settings in October, the autumn weather supported my projected setpoints.

      But we then had 3 weeks away in December and upon returning the wintry weather cycle had begun and I had to change my settings mainly for temperature.

      My wife thinks I am nuts because she sees me constantly changing settings but I am still correcting the settings for the new lower external temps in Jan/Feb.

      So I believe the system will eventually work on a summer and winter schedule - hence I created a MS excel spreadsheet to keep the memo of settings (posted for users benefit elsewhere).

      As some users have suggested, the ability for the controller to hold an alternative schedule of settings would be nice.

      So I have not quite gone insane !!

      Comment

      • MrB
        Automated Home Sr Member
        • Oct 2015
        • 80

        #18
        API can give state as Heat or Off - it always gives Off.

        You can indeed work on the assumption from other data that the current HR92 temp is N, the scheduled temp is T (if, of course, the current time is within the scheduled time period) so it's basic comparison to ASSUME the valve is open or closed. So Smartthing is reporting an assumption not a fact.

        That is not the same as the valve reporting what it is doing, and for fault finding etc that is absolutely what you need.

        Comment

        • paulockenden
          Automated Home Legend
          • Apr 2015
          • 1719

          #19
          There MUST be something in the API that gives zone state, because SmartThings (which is a cloud to cloud integration) shows it.

          P.

          Comment

          • peterf
            Automated Home Guru
            • Jan 2015
            • 116

            #20
            Just a response to killa47's initial query. I've run the system with optimisation on and off both enabled since installation and it's worked fine for me with the radiators coming on up to 70 or 80 minutes early in winter and with virtually no early start in summer.

            The only occasions when it goes awry are when there's a big change in outside temperature which seems to initially catch it out. Note however that if, when using optimisation for off, the system will call for heat again if it drops below 0.5C from what's set.



            Regarding the rogue firing problem that's sometimes reported, I initially had this and I believe that it was down to a two radiator zone where I'd swapped which HR92 was the master. Although the zone appeared to work OK, a suggestion in another post made me wonder if that was the cause of the problem and after deleting the zone and re-creating, the rogue firing went away.

            Comment

            • HenGus
              Automated Home Legend
              • May 2014
              • 1001

              #21
              I confess that I don't really care what the TRVs are doing. Eighteen months or so on from installation, optimisation with the original controller does work as it usually wakes me up every morning. Earlier this week, with an OAT of M5C, the HR92s in my bedroom whirred at 0655am. Today, with the OAT about 10C higher, the HR92s whirred at about 0715am. All that said, it would be nice to have an icon on each zone display to show when a particular zone is asking for heat.

              Comment

              • Krejt
                Automated Home Jr Member
                • Jan 2016
                • 21

                #22
                Originally posted by paulockenden View Post
                There MUST be something in the API that gives zone state, because SmartThings (which is a cloud to cloud integration) shows it.
                Nope Paul, SmartThings simply sees the requested temperature is lower then the actual temperature and concludes the unit/zone is requesting for heat from that info. I've looked into the data the API provides over and over and the 'heat' status always shows OFF. There is no way SmartThings can show something that simply isn't there. Just like MrB said, SmartThings is assuming the valve is open and/of the unit is requesting for heat and shows just that. That is not the same as the unit reporting what it is doing, and the API passing on that info.
                Last edited by Krejt; 21 February 2016, 08:46 AM. Reason: forgot quote
                Evohomeclient temperatures on ThingSpeak: https://thingspeak.com/channels/79213

                Comment

                • rotor
                  Automated Home Guru
                  • Aug 2015
                  • 124

                  #23
                  Originally posted by Krejt View Post
                  Nope Paul, SmartThings simply sees the requested temperature is lower then the actual temperature and concludes the unit/zone is requesting for heat from that info. I've looked into the data the API provides over and over and the 'heat' status always shows OFF. There is no way SmartThings can show something that simply isn't there. Just like MrB said, SmartThings is assuming the valve is open and/of the unit is requesting for heat and shows just that. That is not the same as the unit reporting what it is doing, and the API passing on that info.
                  Hi Krejt, I assume you're talking about the API that we all use for graphing? That is what I would call the "unofficial" API, as it was reverse-engineered from what is used by the phone app. But there is also an "official" API that you have to sign up for (I tried, and never heard back), so I wonder if the official API does provide that information?

                  Comment

                  • top brake
                    Automated Home Legend
                    • Feb 2015
                    • 837

                    #24
                    sounds like a double bind issue, did you factory reset and delete the existing BDR91 binding before creating the new system?

                    Originally posted by graham.gibson View Post
                    I recently fitted Evohome to an S plan system – Worcester Bosch 30CDi conventional boiler, Grundfos Alpha2L pump, Honeywell 2 port zone valves and Honeywell ABV – all about 2 years old. HR92s on all rads. BRD91 as heating valve controller and second BDR91 as hot water valve controller. 12 out of 15 rads have Danfoss RA/VL TRVs with the HR92 adapters. Boiler temp is set to 60 degrees.

                    On the one hand, things are mostly ok – hot water and internet control are perfect and the setpoints are largely maintained in each zone. Sometimes the temp in a zone falls well below setpoint and I have to reset the corresponding HR92 – I suspect this is a symptom of my Danfoss RA/VL valve bodies being old. I have managed to resolve quite a few niggles along the way (and many thanks to Richard from Evohome Shop who has been extremely helpful), but I have a further niggle and I thought I would reach out to the experts on this forum for advice.

                    If I reduce the temp in all zones, the TRVs turn off, but the heating BDR91 remains on for some time before turning off. The BDR91 then comes on from time to time, presumably to keep the temp ‘topped up’ in the zones (or perhaps for some other reason). However, I've noticed in some cases that my heating return pipe remains cool and instead the hot water just circulates round the bypass loop. I don’t know if this is because the HR92s think that they are opening but the underlying RA/VL(s) are not actually opening, or if the HR92s are opening partially such that the flow in the heating circuit is very low and the bypass kicks in to maintain minimum flow rate, or if the BDR91 is firing incorrectly when there is no demand (or some combination of these). When the system is in this state, the boiler gets into a constant cycle of firing up, heating to 60 degrees, going off, water then rises to around 67 degrees as heat is only being dissipated via the bypass loop, cools down below 60 then the boiler fires up again then repeat.

                    What’s troubling me is that when the system gets into this state, all that appears to be happening is that the bypass loop is being heated all night, which seems to be a waste of energy to me and also unnecessary repeated firing of the boiler.

                    I’d welcome any advice on how to definitively troubleshoot this issue. I’m concerned that I’ll have to replace all of my RA/VLs (which is a complete pain as I’ll have to extend the pipework at each rad) or continually waste energy or return to a single zone configuration using a room stat and no TRVs in that room (which would be a waste of Evohome’s capabilities).

                    Thanks,
                    Graham
                    I work for Resideo, posts are personal and my own views.

                    Comment

                    • graham.gibson
                      Automated Home Jr Member
                      • Feb 2016
                      • 11

                      #25
                      Hi,

                      Thanks for all the comments - it's great to see such an active Evohome community.

                      Yes, I did factory reset the BRD91s first.

                      I did a bit of reconfiguration at the weekend and my system *seems* to be behaving itself a bit better now - time will tell if it's fully sorted. The key thing is that the temperature in all zones is tracking at or very close to set point at all times now, and a 24 hour time-lapse that I did of my boiler, pump and BRD91s did not show any alarming increases of boiler temperature that I was getting before. What I did included (which will hopefully be useful to others):
                      • Replaced all of the gland seals in my Danfoss RA/VLs (new pins effectively) - an easy job that can be done without draining down
                      • Re-seated all of the HR92s to be lightly tight just after hitting the pins
                      • A full reset of all components and re-creation of all zones and binding, allowing time when binding for the HR92s to sync
                      • Changed valve stroke to full on a couple of rads that were not heating up as much as they did without HR92s on them
                      • Adjusted my pump and ABV settings to be properly in tandem
                      • Uninsulated 3m of bypass loop as suggested by Richard of Evohome Shop


                      A time lapse that I did last night showed that the heating BRD91 went off at 11pm when the temp in all zones dropped to 16 degrees (I've kept the default controller schedule for now until the system learns the rooms) and it stayed off for a couple of hours. It then came on from time to time, presumably to keep the zones topped up. So far, the temp in all zones has been pretty consistent - under or overshooting only by about half a degree.

                      I'll need to keep an eye on things over the next few days, but my confidence has improved a bit. I suspect the issue I've seen (and maybe that others have seen) is that an HR92 is calling for 'top up' heat (i.e. low demand) but the underlying valve is not opening enough (or at all) so the BDR91 stays on and the water ends up being heated and cooled through the bypass loop in a constant cycle.

                      Regards,
                      Graham
                      Last edited by graham.gibson; 22 February 2016, 11:20 PM.

                      Comment

                      • paulockenden
                        Automated Home Legend
                        • Apr 2015
                        • 1719

                        #26
                        Who on earth put insulation on your bypass loop? That shows a lack of understanding about what the loop is actually for.

                        Comment

                        • graham.gibson
                          Automated Home Jr Member
                          • Feb 2016
                          • 11

                          #27
                          A Worcester Bosch accredited installer.

                          The random BDR91 firing is back. Setpoint of all zones is 16 degrees. Actual temp of all zones is >=20 degrees. BDR91 is still cycling on and off. Seems crazy to be calling for heat when all zones 4 degrees above setpoint. All this is doing is heating the bypass loop - a waste of energy and unnecessary cycling of the boiler.

                          Comment

                          • paulockenden
                            Automated Home Legend
                            • Apr 2015
                            • 1719

                            #28
                            Something is wrong. Your zones are well above the TPI band.

                            Comment

                            • paulockenden
                              Automated Home Legend
                              • Apr 2015
                              • 1719

                              #29
                              It's going to sound bonkers, but I'd suggest manually going round the house and removing the HR92s (or just flicking the in lip switch) on them, until you identify the culprit.

                              Rather than doing them sequentially, a binary chop might be quicker. Do half, then half of those, etc.

                              Just remember that the effect won't be instant - you might need to wait 20-30 mins to see whether the random firing stops.

                              Hopefully you'll narrow it down to one HR92 calling for heat when it shouldn't.

                              Comment

                              • Rameses
                                Industry Expert
                                • Nov 2014
                                • 446

                                #30
                                Did this get sorted?

                                (Been away so replying late) but what you originally stated pointed to a double bind.
                                getconnected.honeywell.com | I work for Honeywell. Any posts I make are purely to help if I can. Any personal views expressed are my own

                                Comment

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