Evohome - large temperature overshoots

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  • Mavis
    Automated Home Ninja
    • Oct 2014
    • 322

    #16
    Now spring is here, our sitting room (south facing) gets a lot hotter but the heating still comes on. I think, as someone else has mentioned there should be the facility to have different season schedules. In winter, I have found that room temperatures are much more straight forward in the winter as the external temp and sun heat on windows are very low. Now it is spring the sun radiation has a bigger influence in the room

    I have optimisation still switched on and the OPT Off at this time of year kicks in at least three quarters of an hour before the setpoint so the heating 'switches off' around 9.40pm (with a night setpoint of 10C at 10.30pm) There is no noticeable difference in the temp.

    I now have my IFTTT geofencing recipe switched on all the time (to turn on Economy Mode when I leave the house and on when I return - I work Mon to Fri) and the rest of the family have not complained that the house is too cold. I guess I should really change the schedule so that there is only a burst of heat in the morning and then around 6ish in the evening.

    Comment

    • f1arp72
      Automated Home Jr Member
      • Apr 2015
      • 48

      #17
      Originally posted by erik View Post
      @f1arp72: I hope leaving it running/learning for some time will fix it for you. I have personally tried Evohome 18 months (2 winters) and it has always continued to overshoot big time for me (only to cool down and then overshoot again). I have given up on it myself and am using a very simple cheap thermostat now, that keeps everything nicely around the desired temperature. However, there's other folks here who don't have these problems, so it might start working fine for you as well!
      @eirk: So have you abandoned the Evohome system completely then and replaced with an old fashioned thermostat?

      @Mavis: I agree outside temperatures are now possibly having an effect but we've not reached 23 outside yet, and last night it definitely wasn't that warm outside when I got home? I guess under "old" conditions I'd have heating switched off now and wouldn't be "worrying" about what my heating system is doing


      I just can't get my head around this system. Woke up this morning and was told by Evohome that both rooms downstairs were 19. However, standard thermostats I have sitting in each room were showing 22 and 21 meaning the rooms did not require heating. However, Evohome came on and started heating them. Surely there can't be a 3 degrees difference between the height of a table top thermostat and the floor where the rad valves are ??

      If I was to guess given on how the room "felt", I would believe the 22 of the thermostat as opposed to the 19 of the Evohome rad !!

      Comment

      • paulockenden
        Automated Home Legend
        • Apr 2015
        • 1719

        #18
        Originally posted by f1arp72 View Post
        Surely there can't be a 3 degrees difference between the height of a table top thermostat and the floor where the rad valves are ??
        Why not put your old fashioned thermostat near (or even standing on top of) the rad valve?

        P.

        Comment

        • Bazinga
          Automated Home Jr Member
          • Feb 2015
          • 22

          #19
          @f1arp72: Have you perhaps inadvertently adjusted the Temperature Offset on the HR92 TRVs? It's parameter 8 in the Parameters menu. If you have Parameter 8 set to -3, then this would explain your symptoms. I would then try returning back to 0 and then monitor it for a couple of days.
          In my experience the HR92s do a good job of estimating the temperature, but can struggle when a room takes a while heating up. In those cases it will over-read. I solved this in one of our rooms by adding a DT92E room thermostat. I haven't seen them under-read however, unless the Parameter 8 is set to a negative number.

          Comment

          • f1arp72
            Automated Home Jr Member
            • Apr 2015
            • 48

            #20
            Originally posted by paulockenden View Post
            Why not put your old fashioned thermostat near (or even standing on top of) the rad valve?

            P.
            Yeah, I thought of that and will give it a go tonight. Thanks

            Originally posted by Bazinga View Post
            @f1arp72: Have you perhaps inadvertently adjusted the Temperature Offset on the HR92 TRVs? It's parameter 8 in the Parameters menu. If you have Parameter 8 set to -3, then this would explain your symptoms. I would then try returning back to 0 and then monitor it for a couple of days.
            In my experience the HR92s do a good job of estimating the temperature, but can struggle when a room takes a while heating up. In those cases it will over-read. I solved this in one of our rooms by adding a DT92E room thermostat. I haven't seen them under-read however, unless the Parameter 8 is set to a negative number.
            Thanks for the suggestion but no, parameter 8 is untouched and set to zero. I think this may be to do with the fact the rad valve isn't in the greatest position (in lounge under window) so I'm probably getting the colder air coming through window and falling on to rad valve? I do like the idea of maybe switching to a DT92E if I can't find another solution. Would I have to delete the zone then recreate with DT92E. I presume I have to somehow bind the DT92E to the HR92 ?

            Comment

            • Bazinga
              Automated Home Jr Member
              • Feb 2015
              • 22

              #21
              Originally posted by f1arp72 View Post
              Thanks for the suggestion but no, parameter 8 is untouched and set to zero. I think this may be to do with the fact the rad valve isn't in the greatest position (in lounge under window) so I'm probably getting the colder air coming through window and falling on to rad valve? I do like the idea of maybe switching to a DT92E if I can't find another solution. Would I have to delete the zone then recreate with DT92E. I presume I have to somehow bind the DT92E to the HR92 ?
              That's how I did it. Not sure if there is a shortcut, but I thought it was safer to start with a new zone. The DT92E was bound to the Evohome controller first then the HR92.

              Comment

              • f1arp72
                Automated Home Jr Member
                • Apr 2015
                • 48

                #22
                Originally posted by Bazinga View Post
                That's how I did it. Not sure if there is a shortcut, but I thought it was safer to start with a new zone. The DT92E was bound to the Evohome controller first then the HR92.
                Thanks. I'll keep this as an option if I can't get the room "balanced" as I want it. I'm reluctant to delete a zone and rebind anything as it seems this system can easily get "confused" and I've reset and set up from scratch enough times in the last week !!

                Comment

                • Mavis
                  Automated Home Ninja
                  • Oct 2014
                  • 322

                  #23
                  Here is a link to a thread I was participating in as I was having problems setting up my DT92E. There is a Dutch youtube video in this link also which was very good. You will also be able to read some of my concerns and problems setting it up. (you may have to scroll up or down to find where I started)

                  Comment

                  • paulockenden
                    Automated Home Legend
                    • Apr 2015
                    • 1719

                    #24
                    You don't have to delete the zone to use a DT92. Just edit the zone, select the temp source and you'll get an option to bind a sensor.

                    Comment

                    • erik
                      Automated Home Guru
                      • Feb 2015
                      • 244

                      #25
                      Originally posted by f1arp72 View Post
                      @eirk: So have you abandoned the Evohome system completely then and replaced with an old fashioned thermostat?
                      Yes, can't get Evohome to behave at my place for some reason. But let's just focus on your problem and try to fix it and not give up beforehand

                      Anyway, instead of DT92 you can also use a Round Wireless as a temperature sensor for the room. Might be cheaper/prettier. There's stores that sell them seperately. (without BDR91 boiler relay and without RFG100 gateway)

                      Mavis: are you in NL? Or just happened to run in to a dutch youtube?
                      Last edited by erik; 6 May 2015, 01:25 PM.

                      Comment

                      • f1arp72
                        Automated Home Jr Member
                        • Apr 2015
                        • 48

                        #26
                        Thanks everyone. I hope I start to trust this system more and we start to get on better. We've not had the best start to our relationship !!!

                        Comment

                        • f1arp72
                          Automated Home Jr Member
                          • Apr 2015
                          • 48

                          #27
                          Ok, my trust issues continue. This morning, with all rooms set to 21, after an hour and a half when system went off at 8am, my rooms were ...

                          Room: From > To
                          Lounge: 19 > 23
                          Breakfast Room: 18.5 > 22
                          Conservatory: 17 > 21
                          Hallway: 19.5 > 20.5 (never reached target)
                          Bedroom: 20.5 > 21.5
                          Bathroom: 20 > 20.5 (never reached target)

                          Other two bedrooms were 22 and didn't heat up

                          So, two rooms never reached target, three rooms overshot by 2 degrees and 1 degree and half a degree (although the latter I would expect and be happy with), but two rooms never reached target, both of which I know are capable of heating up way faster than the hour and a half this system was active).

                          I just don't get it.

                          This thing is taking over my life. I'm waking up in the middle of the night to see if, for some unknown reason the boiler has fired up for one of it's odd 10 minute off / 1 minute on cycles. I'm waking up early in the morning to stare at temperatures to wait and see whet the system does. I was sat with a pencil and paper next to my boiler last night timing the thing having now found out that it fires up every 10 minutes for 1 minute even when all rooms are at Setpoint.

                          I want my life back I NEED to stop watching this thing and let it get on with things. At the end of the day, it's how the house / rooms "feel" that matters and it's the wrong time of year as outside temperatures and playing their part. I'm going to turn heating down for the summer and see how things go when it turns again in the Autumn.

                          Just wanted to say thanks to everyone on these forums for their help and feedback.

                          Comment

                          • paulockenden
                            Automated Home Legend
                            • Apr 2015
                            • 1719

                            #28
                            If you search around you'll find a Python script that reports the temps (as reported by your HR92s or whatever else you have as a sensor in the zone) every five minutes. That'll drive you even madder!

                            Suggestion (Not a solution, but might allow you to sleep better): Those two zones that didn't reach temp - set them to come on 20mins earlier than the others.

                            Oh, and check that the rads are hot to the top (i.e. don't need bleeding).

                            Comment

                            • Mavis
                              Automated Home Ninja
                              • Oct 2014
                              • 322

                              #29
                              Originally posted by f1arp72 View Post
                              Ok, my trust issues continue. This morning, with all rooms set to 21, after an hour and a half when system went off at 8am, my rooms were ...

                              Room: From > To
                              Lounge: 19 > 23
                              Breakfast Room: 18.5 > 22
                              Conservatory: 17 > 21
                              Hallway: 19.5 > 20.5 (never reached target)
                              Bedroom: 20.5 > 21.5
                              Bathroom: 20 > 20.5 (never reached target)

                              Other two bedrooms were 22 and didn't heat up

                              So, two rooms never reached target, three rooms overshot by 2 degrees and 1 degree and half a degree (although the latter I would expect and be happy with), but two rooms never reached target, both of which I know are capable of heating up way faster than the hour and a half this system was active).

                              I just don't get it.

                              This thing is taking over my life. I'm waking up in the middle of the night to see if, for some unknown reason the boiler has fired up for one of it's odd 10 minute off / 1 minute on cycles. I'm waking up early in the morning to stare at temperatures to wait and see whet the system does. I was sat with a pencil and paper next to my boiler last night timing the thing having now found out that it fires up every 10 minutes for 1 minute even when all rooms are at Setpoint.

                              I want my life back I NEED to stop watching this thing and let it get on with things. At the end of the day, it's how the house / rooms "feel" that matters and it's the wrong time of year as outside temperatures and playing their part. I'm going to turn heating down for the summer and see how things go when it turns again in the Autumn.

                              Just wanted to say thanks to everyone on these forums for their help and feedback.
                              Welcome to our world

                              I think we have all been there and done that - I know that I have had the controller beside my bed and spent all night checking it.

                              Comment

                              • roydonaldson
                                Automated Home Guru
                                • Jan 2013
                                • 205

                                #30
                                Quick question on your rooms that didn't reach temperature. Are the radiators of the right size such that they can heat the rooms up to that temperature ?

                                When I first moved in to my house the hallway was never warm. Having then checked the size of the 2 radiators in the hallway, they did not put out enough BTU's to be able to heat the hallway above about 18. Changed both radiators using a BTU calculator for the size of the room to double their size and it's fine now.

                                Roy.

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