Evohome - boiler on VERY frequently

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  • Rameses
    Industry Expert
    • Nov 2014
    • 446

    #16
    Originally posted by garmcqui View Post
    Some very interesting information here. Am also reading through thw following post with interest, as it seems to be a similar problem:



    Might seem like a daft idea, but last night I set up a video camera to record the status display of the boiler all night. I will review the footage in more detail this weekend but from a quick glance this morning, it seems the boiler is coming on for approx 1 minute every 10 minutes, all night. All HR92's were set to 5C overnight except our bedroom, which was set to 18C (we have a 4 week old baby so room needs to stay warmish).

    Also, had a quick look in the advanced settings. Am I right in thinking that as I don't have an actual boiler relay (boiler controlled by zone valves) then I can't set variables such as the cycle rate and minimum on time?

    You can change the 'cycle' time in the installer menu>systems parameters > cycle rate. But the default is 6 cycles per hour. You could change down to 3 - but the system will dump more heat, less frequently. You cannot have Zero cycles per hour when there is a requirement for heat. 12 is used for electric heating usually - hence 6 is the recommended default.
    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

    • jonstatt
      Automated Home Guru
      • Feb 2015
      • 111

      #17
      Originally posted by garmcqui View Post
      Some very interesting information here. Am also reading through thw following post with interest, as it seems to be a similar problem:



      Might seem like a daft idea, but last night I set up a video camera to record the status display of the boiler all night. I will review the footage in more detail this weekend but from a quick glance this morning, it seems the boiler is coming on for approx 1 minute every 10 minutes, all night. All HR92's were set to 5C overnight except our bedroom, which was set to 18C (we have a 4 week old baby so room needs to stay warmish).

      Also, had a quick look in the advanced settings. Am I right in thinking that as I don't have an actual boiler relay (boiler controlled by zone valves) then I can't set variables such as the cycle rate and minimum on time?
      You can't set it with S or Y-plan models but Honeywell have not given any explanation as to why those options "couldn't" be enabled for this scenario, only that they haven't "yet" done so. We are also still waiting to hear what the defaults for cycles and run-time are in those modes.

      Comment

      • garmcqui
        Automated Home Guru
        • Jan 2015
        • 119

        #18
        Originally posted by Rameses View Post
        You can change the 'cycle' time in the installer menu>systems parameters > cycle rate. But the default is 6 cycles per hour. You could change down to 3 - but the system will dump more heat, less frequently. You cannot have Zero cycles per hour when there is a requirement for heat. 12 is used for electric heating usually - hence 6 is the recommended default.
        Thanks Rameses,

        This setting is available even with my S-plan setup?

        Comment

        • orange
          Automated Home Guru
          • Dec 2014
          • 149

          #19
          Originally posted by erik View Post
          Rameses: isn't orange saying he often sees the BDR91 light coming on for 1 minute even though minimum on time is set to 5? Regardless of what boiler is connected and regardless of what logic/intelligence is built in the boiler, that bdr91 behavior is just wrong.

          I personally haven't seen this behavior by the way. When I have set minimum on time to 2 or 3, it usually respects that setting.
          Yes - that's exactly what I'm saying. I know the difference between evohome requesting heat and the boiler logic firing up the boiler.

          It makes no sense and seems inefficient to me ? Plus what is that min time setting ?

          Comment

          • Rameses
            Industry Expert
            • Nov 2014
            • 446

            #20
            Originally posted by garmcqui View Post
            Thanks Rameses,

            This setting is available even with my S-plan setup?
            Yes - and the action of opening of the valve will fire the boiler (have the same at home)
            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

            • jonstatt
              Automated Home Guru
              • Feb 2015
              • 111

              #21
              Originally posted by Rameses View Post
              Yes - and the action of opening of the valve will fire the boiler (have the same at home)
              It's not there on an s-plan set-up! It is only there if you have a boiler relay BDP91 which is a heating only configuration, or a figure 4 configuration

              Comment

              • garmcqui
                Automated Home Guru
                • Jan 2015
                • 119

                #22
                afraid I'm the same as Jonstatt - I don't have this option either as I don't have an actual boiler relay.


                So, I did some (rather sad) investigating overnight, and found that my Evohome system is calling for heat every 10 mins but only for about 30-40 seconds. I have used a couple of old IP cams I had laying around to video the boiler status display and, separately, the BDR91 relay box. This is a tiny sample from the video (which is hours long):



                The video shows separate shots of the BDR91 and the boiler at or around 3.05am (time stamps aren't exactly sync'd, one camera was slightly behind - but it does serve to show how long the heat demand was).

                As you can see in the first part, there is an extremely short call for heat from the relay box lasting only about 30-40 seconds. The second part of the video (blurry I know) shows the boiler's response, initiating firing and then actually firing - but by the time it has fired, Evohome has switched it off again, so the boiler is in action for maybe 10 seconds - which is as good as useless.

                This repeats every 10 mins. Why would Evohome be calling for heat every 10 mins, for less than 30 seconds each time? This can't be good for the boiler itself, especially as the pump and fan run on for 5mins after each of these pathetic 10 second runs!

                Something's not right, and I doubt it's the binding.

                ANY advice appreciated.
                Last edited by garmcqui; 14 March 2015, 06:57 PM.

                Comment

                • top brake
                  Automated Home Legend
                  • Feb 2015
                  • 837

                  #23
                  Originally posted by garmcqui View Post
                  afraid I'm the same as Jonstatt - I don't have this option either as I don't have an actual boiler relay.


                  So, I did some (rather sad) investigating overnight, and found that my Evohome system is calling for heat every 10 mins but only for about 30-40 seconds. I have used a couple of old IP cams I had laying around to video the boiler status display and, separately, the BDR91 relay box. This is a tiny sample from the video (which is hours long):



                  The video shows separate shots of the BDR91 and the boiler at or around 3.05am (time stamps aren't exactly sync'd, one camera was slightly behind - but it does serve to show how long the heat demand was).

                  As you can see in the first part, there is an extremely short call for heat from the relay box lasting only about 30-40 seconds. The second part of the video (blurry I know) shows the boiler's response, initiating firing and then actually firing - but by the time it has fired, Evohome has switched it off again, so the boiler is in action for maybe 10 seconds - which is as good as useless.

                  This repeats every 10 mins. Why would Evohome be calling for heat every 10 mins, for less than 30 seconds each time? This can't be good for the boiler itself, especially as the pump and fan run on for 5mins after each of these pathetic 10 second runs!

                  Something's not right, and I doubt it's the binding.

                  ANY advice appreciated.
                  The 3am is significant, it is the start of a new day.

                  I heard of this before and if I remember correctly it was incorrect binding to do with the Heating relay being double bound as boiler relay.
                  You need to do a clear binding on both heating and hot water relays (hold down grey button for 15 seconds, yes 15 seconds until the red light blinks 0.1 sec on 0.5 seconds off

                  Then go into installer mode, system devices and make sure under 'heat demand' it says NONE
                  Then in installer mode do guided config for the HOT WATER path, bind the hot water sensor then bind the BDR91 relays as 2 x 2 ports, heating and hot water respectively

                  You don't need to redo the guided config for the zones if you don't want, existing settings will not have been erased

                  Let me know if this resolves this behaviour, thanks!
                  I work for Resideo, posts are personal and my own views.

                  Comment

                  • garmcqui
                    Automated Home Guru
                    • Jan 2015
                    • 119

                    #24
                    Hi Top Brake,

                    It wasn't just 3am though, I just happened to choose this time as an example. The same thing happened at from 10am last night (when I started recording), then 10.10, 10.20, 10.30 and every 10 minutes (approx) all the way through until 5am when the boiler came on for longer due to hot water demand.

                    Regarding the double binding - since installing it, I have always had the "Boiler Demand" set to NONE - but Rameses above seemed to suggest that myself and Jonstatt should be able to see settings such as cycle rate, minimum on time etc, which we couldn't.

                    Tonight I have done a factory reset on the Evohome controller, removed the batteries for 30+ mins, done a hard reset on each HR92 and cleared the binding on both BDR91 relays.

                    I am now in the process of slowly rebinding them, being sure to leave plenty of time between each one so as not to confuse it.

                    Thanks, and apologies if the above is confusing!

                    Gareth
                    Last edited by garmcqui; 14 March 2015, 08:03 PM.

                    Comment

                    • erik
                      Automated Home Guru
                      • Feb 2015
                      • 244

                      #25
                      Was there a zone that was anywhere close to the setpoint? In other words: was there any reason for the boiler to be fired at all?

                      I've personally never seen Evohome firing my boiler when there was no zone to request heat (all set to OFF for example). If you would see it, I would suspect misconfiguration and that the reset/rebind would fix that.

                      Let's wait and see

                      If there WAS a zone rightfuly requesting heat, then the question would be how to raise the minimum ON time. 30-40 seconds is useless indeed and I thought the minimum always was 1 minute?
                      Last edited by erik; 14 March 2015, 10:28 PM.

                      Comment

                      • Rameses
                        Industry Expert
                        • Nov 2014
                        • 446

                        #26
                        Gareth (garmcui) let us know how it goes.

                        Agree with topbrake - this behaviour is consistent to double binding. Interesting fact - the BDR91 has 4 'address slots' internally for binding (Top brake will correct me here I am sure).

                        The minimum on time setting (under system parameters) is "This setting is used to prevent damage to the boiler by allowing it to keep running until it has stabilised before shutting down" / Check the boiler manufacturer handbook for the required minimum on time for your boiler"
                        <copied this from the ? hint in the device menu >

                        When you do get around to setting this - the default is 1min - but check your boiler specs (some larger older ones might be longer etc)
                        Last edited by Rameses; 14 March 2015, 11:18 PM.
                        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

                        • garmcqui
                          Automated Home Guru
                          • Jan 2015
                          • 119

                          #27
                          thank you both for your replies.

                          There was a room which was being kept at 18C all night (due to new baby), all other zones were set at 5C overnight so were all well above the setpoint.

                          However, with regards to amending the minimum on time and cycle rate, like Jonstatt, I can't amend this as I don't have a boiler relay.

                          The boiler has a manufacturing date of 2014 (house is a new build) , so not old.

                          Comment

                          • top brake
                            Automated Home Legend
                            • Feb 2015
                            • 837

                            #28
                            Originally posted by Rameses View Post
                            Gareth (garmcui) let us know how it goes.

                            Agree with topbrake - this behaviour is consistent to double binding. Interesting fact - the BDR91 has 4 'address slots' internally for binding (Top brake will correct me here I am sure).

                            The minimum on time setting (under system parameters) is "This setting is used to prevent damage to the boiler by allowing it to keep running until it has stabilised before shutting down" / Check the boiler manufacturer handbook for the required minimum on time for your boiler"
                            <copied this from the ? hint in the device menu >

                            When you do get around to setting this - the default is 1min - but check your boiler specs (some larger older ones might be longer etc)
                            Indeed 4 binding slots in a BDR91, very rare that you would need to use them all. Most I have seen being 3 x evo bound into one BDR91 boiler relay (mansion with 3 floors...)

                            As previously advised you need to match the evohome to your application and if your boiler would benefit from specific cycle rate and minimum run time you need to install the system with a boiler relay.
                            This is possible in both combination and heat only boilers.
                            The only reason evohome is supported for S Plan and Y Plan is to make retrofit easy. If you have a new stored hot water installation go for Figure 4 (single hot water valve and boiler relay).

                            A fully optimised installation will also include a system bypass valve, and on modern high efficiency condensing boilers you may need to set up flow and return temperatures and anti cycling parameters.
                            In this case your heating engineer should be consulted.
                            I work for Resideo, posts are personal and my own views.

                            Comment

                            • garmcqui
                              Automated Home Guru
                              • Jan 2015
                              • 119

                              #29
                              Hi top brake.

                              A system bypass and valve is already in place.

                              The figure 4 setup would require replacing the existing 2 port valves for a three port valve - yes?

                              I see what you say about consulting a heating engineer, but regarding flow and return temperatures, or the boiler's cycling parameters, I can see how these would be important if it were the boiler itself which was determining the time to come on and turn off, but in my case the Evohome system is turning the boiler on for a useless amount of time, as evidemced by the relay in the video.

                              I will monitor the boiler and relay overnight again to see if the full reset has done any good.

                              I hope so. Will report back tomorrow.

                              Thanks

                              Comment

                              • top brake
                                Automated Home Legend
                                • Feb 2015
                                • 837

                                #30
                                Originally posted by garmcqui View Post
                                Hi top brake.

                                A system bypass and valve is already in place.

                                The figure 4 setup would require replacing the existing 2 port valves for a three port valve - yes?

                                I see what you say about consulting a heating engineer, but regarding flow and return temperatures, or the boiler's cycling parameters, I can see how these would be important if it were the boiler itself which was determining the time to come on and turn off, but in my case the Evohome system is turning the boiler on for a useless amount of time, as evidemced by the relay in the video.

                                I will monitor the boiler and relay overnight again to see if the full reset has done any good.

                                I hope so. Will report back tomorrow.

                                Thanks
                                No need to replace any valve, you can simply latch open the existing 2 port heating valve or remove it. Then re-use the existing heating relay as a boiler relay. When installing like this you need HR92 on the radiators. There is a small typo in the evohome manual at figure 4, should say V4043.

                                I am not saying you need to make adjustments to the boiler, your boiler installer may need to change the settings for you now an evohome system is installed if previously no TRV were fitted. A modern high efficiency condensing boiler is a very sophisticated appliance with a modulating gas valve and clever control electronics (incidentally often made by Honeywell). The Honeywell product design and development team understands these capabilities and evohome was developed to work in harmony.
                                I work for Resideo, posts are personal and my own views.

                                Comment

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