Tracking down random boiler demand with Evohome

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  • orange
    Automated Home Guru
    • Dec 2014
    • 149

    Tracking down random boiler demand with Evohome

    My evohome is controlling a combi - so no hot water via evohome.

    I've gone to bed (it's been a very long day) so currently only one (of 12 zones) active. Rest set to 5deg. No local overrides set.

    Optimised start/stop is active (max 1 hour). No programmed set points until tomorrow so shouldn't be any optimised startups in progress.

    Set point on active zone is 22 degrees c. Current temp on this zone is 23degrees so no demand for heat.......so why can I hear my boiler starting up every 10 minutes or so ??? running for 10 minutes and switching off. (Rinse/repeat) Been happening for the last hour or so.

    Evohome is demanding heat as the bdr91 light comes on (I've been out of bed to check). Controller and rad control both show 'over' the set point.


    Why the boiler demand ?

    Don't feel like I'm saving my 45% on heating bills at the moment
  • Rameses
    Industry Expert
    • Nov 2014
    • 446

    #2
    Temperature is never static - its either rising or falling.

    In the case above - the boiler is being 'throttled' to maintain your 22 degrees. Just because its 1 degree above what you want - doesn't mean that evohome wont predict the heat loss curve of the room. Eg if it waited until 22 degrees, then by the time the boiler had fired and the rads had filled, and then effect had started to take place - then the room could be at 19 degrees, at which point your comfort is compromised and the boiler has to play catchup.

    PS If you absolute control (by this I mean only a call for heat when a specific value is achieved) - then turn optimisation off.
    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

    • orange
      Automated Home Guru
      • Dec 2014
      • 149

      #3
      I partially agree - but in the last hour the boiler has fired on and off about 6 times. The temp has never dropped below 1 degree ABOVE the set point.

      I can understand evohome doing this once.....but every 5 to 10 minutes - 3 more times since that last post. That doesn't seem smart at all ? That seems to assume the heat loss curve was nearly vertically downwards ie it needs to top up every 10 minutes to 1 degree above the set point.

      It's not a new install so it should know the correct curve ?

      I have what I thought was a max boiler cycling option set in the controller too (think its 6 per hour?)

      Comment

      • The EVOHOME Shop
        Site Sponsor
        • Dec 2014
        • 483

        #4
        Originally posted by orange View Post
        Why the boiler demand ?

        Don't feel like I'm saving my 45% on heating bills at the moment
        This could well be the fact you have bound your system incorrectly or double bound an item. I've seen this happen a few times with my customers and all have been because they have bound something incorrectly or rushed the binding process, especially using guided config. Once I have walked them through a complete rebinding process this has been eliminated.

        I would suggest a rebind of the system, be sure to unbind everything completely and rebind everything maliciously.

        I only normally technically help my own customers, but seems you have had some issues so maybe give me a call and I will help - 07884 110955.

        Thanks,

        Richard

        Comment

        • orange
          Automated Home Guru
          • Dec 2014
          • 149

          #5
          thanks Richard - I gave up and switched the heating off in the end

          I'll try rebinding - but it's odd as that's been working fine for the last few months. I'm fairly convinced it's not double bound and temps report back fine to the controller and the controller seems to talk to the valve ok plus local override works ? Easy enough to rebind.

          Thanks also for the offer of support (I did get the system from you originally) It's not really a show stopper but I think it's important that honeywell add some kind of logging to their system - then it would be easy to spot what was going on in this instance.

          Comment

          • G4RHL
            Automated Home Legend
            • Jan 2015
            • 1580

            #6
            My only thoughts are as The Evohome Shop suggests, try re-doing the whole lot. It means a factory reset of all, power off and batteries out for a bit for the Controller. A pain but it could well clear the issue. For other reasons I did an electronic reinstall of everything last weekend. I had issues with the hot water in that it was not coming on when it should nor going off. It seemed to trigger when I did not want it. The answer was something had happened in the binding process that I think left the heating relay bound before the hot water one. Having learned so much from these pages (and yes most ought to be in the manual) I just took my time going through each step carefully ensuring it all was setting up as it showed.

            After ensuring all was reset and nothing anywhere was bound the sequence was bind water sensor to controller, bind hot water relay to the controller, bind heating relay to the controller, ensure optimisation, choose number of zones and then one by one slowly ensuring each TRV was bound after first ensuring each was the temperature sensor and not the controller. Fished off with binding the Gateway. All works and as it works for most readers it just could be a binding has not occurred as it should.

            Remember to wait a few minutes after doing the binding and not to rush off to do the next one as this gives the system that moment to build up its memory. The syncing of each TRV only took a few minutes.

            It all does work well. Indeed I came in the back door this morning, looked at the control panel which is next to the boiler and noticed the hall TRV was showing there was an open window. No windows in the hall so assumed a parcel must have been delivered and my wife had open and shut the front door! Almost like big brother!

            My only issue now is using the app on my iPhone when roaming but I think I may have an inkling now of what the problem is - mine, not Honeywell's!

            Always remember that a lot of problems are caused by user error, i.e we create them with playing around! But then if we did not play around with these things we would not come across actual issues nor ideas for the future! Helpful though to have a proper manual.

            Comment

            • The EVOHOME Shop
              Site Sponsor
              • Dec 2014
              • 483

              #7
              Originally posted by orange View Post
              thanks Richard - I gave up and switched the heating off in the end

              I'll try rebinding - but it's odd as that's been working fine for the last few months. I'm fairly convinced it's not double bound and temps report back fine to the controller and the controller seems to talk to the valve ok plus local override works ? Easy enough to rebind.

              Thanks also for the offer of support (I did get the system from you originally) It's not really a show stopper but I think it's important that honeywell add some kind of logging to their system - then it would be easy to spot what was going on in this instance.
              If you bought the system from us, then deffo give me a call. I really do support every sale, so please don't think you cannot call me! One thing I pride myself on is helping my customers who have invested in a system we have supplied.

              Comment

              • orange
                Automated Home Guru
                • Dec 2014
                • 149

                #8
                Originally posted by G4RHL View Post
                My only thoughts are as The Evohome Shop suggests, try re-doing the whole lot. It means a factory reset of all, power off and batteries out for a bit for the Controller. A pain but it could well clear the issue. For other reasons I did an electronic reinstall of everything last weekend. I had issues with the hot water in that it was not coming on when it should nor going off. It seemed to trigger when I did not want it. The answer was something had happened in the binding process that I think left the heating relay bound before the hot water one. Having learned so much from these pages (and yes most ought to be in the manual) I just took my time going through each step carefully ensuring it all was setting up as it showed.
                the only problem I have is that the 'start over again' approach may or may not fix it. What Honeywell need to do when they have problems is to find the cause of them so they can fix it for everyone.

                For example - the issues you've been having were (partially) fixed by a deleting your account and starting again (essentially) - that's not a fix as far as I'm concerned. Obviously as an end user you might not care as you're just happy to have it working. That doesn't mean that the same issue isn't going to bite you again or other users. It seems the support guys have no real access to the developers so all they are left with no alternative than just turn it off and on again

                Comment

                • The EVOHOME Shop
                  Site Sponsor
                  • Dec 2014
                  • 483

                  #9
                  Well what I find is most people rush the binding process and as they do not do multiple systems like I do, don't realise when the binding has gone wrong. By talking over the phone with me, I can reassure you are binding the system correctly and at least then if there are still issues, you have eliminated binding from the equation.

                  Comment

                  • orange
                    Automated Home Guru
                    • Dec 2014
                    • 149

                    #10
                    hi Richard - thanks again for the kind offer - how do you know if the binding has gone wrong ? Any symptoms apart from general weirdness ?

                    only one sensor/valve per zone and all working fine - reporting temps and controlling fine - radio strength ok - local override works as expected - no logged errors - optimum start working fine on all zones etc. Happy to rebind (and will) but not sure what we should be looking out for as a fault to guide us ?

                    My suspicion is that it's calculated the heat loss curve for the room either incorrectly or strangely. Basically it's scared to let it drop down to the set point as it's not sure it can bring the temperature up quickly enough (essentially what Ramases is saying) - In this instance it would seem to me that the system should arrange a larger hysteresis loop for the temperate rather than quickly cycling the boiler every few minutes.....

                    what I'm I think I'm saying is I think this is a 'feature' not a fault.

                    decent logging would of course let us know

                    Comment

                    • ally153
                      Automated Home Jr Member
                      • Nov 2014
                      • 30

                      #11
                      Originally posted by orange View Post
                      hi Richard - thanks again for the kind offer - how do you know if the binding has gone wrong ? Any symptoms apart from general weirdness ?

                      only one sensor/valve per zone and all working fine - reporting temps and controlling fine - radio strength ok - local override works as expected - no logged errors - optimum start working fine on all zones etc. Happy to rebind (and will) but not sure what we should be looking out for as a fault to guide us ?

                      My suspicion is that it's calculated the heat loss curve for the room either incorrectly or strangely. Basically it's scared to let it drop down to the set point as it's not sure it can bring the temperature up quickly enough (essentially what Ramases is saying) - In this instance it would seem to me that the system should arrange a larger hysteresis loop for the temperate rather than quickly cycling the boiler every few minutes.....

                      what I'm I think I'm saying is I think this is a 'feature' not a fault.

                      decent logging would of course let us know
                      In a radiator based system, chances are there isn't a double-bind of a device to the boiler relay - usually this happens when someone re-uses a hot water relay as a boiler relay (or vice versa) without clearing the binding. I'm assuming your system was recently installed? When Evo is first installed, all zones have a pretty standard heat curve, which is optimised over time as the device learns how each room of your house reacts.

                      The standard parameters off a boiler would be 6 cycles per hour with a minimum on time of 1 minute (this is to prevent potential damage from trying to actuate a valve too often). Judging from your description, I'm guessing the boiler comes on for a minute every 10 minutes. Like Ramses mentioned, due to the heat loss curve, Evo has decided there is some, very small requirement for heat, so turns on the boiler for the minimum permissible on time of 1 minute.

                      I'd say you're best giving the system time to learn how best to control your home. You'll most likely be saving money over-all by having a fully zoned heating system over a more basic heating system either way.

                      Comment

                      • orange
                        Automated Home Guru
                        • Dec 2014
                        • 149

                        #12
                        Originally posted by ally153 View Post
                        In a radiator based system, chances are there isn't a double-bind of a device to the boiler relay - usually this happens when someone re-uses a hot water relay as a boiler relay (or vice versa) without clearing the binding. I'm assuming your system was recently installed? When Evo is first installed, all zones have a pretty standard heat curve, which is optimised over time as the device learns how each room of your house reacts.

                        The standard parameters off a boiler would be 6 cycles per hour with a minimum on time of 1 minute (this is to prevent potential damage from trying to actuate a valve too often). Judging from your description, I'm guessing the boiler comes on for a minute every 10 minutes. Like Ramses mentioned, due to the heat loss curve, Evo has decided there is some, very small requirement for heat, so turns on the boiler for the minimum permissible on time of 1 minute.

                        I'd say you're best giving the system time to learn how best to control your home. You'll most likely be saving money over-all by having a fully zoned heating system over a more basic heating system either way.
                        the system has been in for a few months - it should have learned the heat gain/loss curves by now. My minimum on time is set to 5 minutes but apart from that your correct. My point is that quick cycling the boiler like that for short durations cannot (?) be efficient - therefore the controller logic needs some refinement ?

                        FWIW the room temp and radiator temp didn't change more than .5 degree during the short cycling and never dropped as low as the set point.

                        Comment

                        • HenGus
                          Automated Home Legend
                          • May 2014
                          • 1001

                          #13
                          I have had issues with Comms actuator faults - often in the quiet hours when there is no demand for heat for HW or CH. Occasionally, my sleep has been disturbed by the pump coming on followed by the boiler for about a minute. Looking at the Evohome log, the boiler cycles appear to occur when the BDRs are in a fault condition. I am not sure how this relates to your issues but all I can say is that when BDRs are operating as they should, my boiler doesn't short cycle. Wifi interference, perhaps, which is not bad enough to trigger a Comms fault in the log?

                          My BDRs have just been moved well away from anything metallic or electrical.

                          Comment

                          • The EVOHOME Shop
                            Site Sponsor
                            • Dec 2014
                            • 483

                            #14
                            Originally posted by orange View Post
                            hi Richard - thanks again for the kind offer - how do you know if the binding has gone wrong ? Any symptoms apart from general weirdness ?

                            only one sensor/valve per zone and all working fine - reporting temps and controlling fine - radio strength ok - local override works as expected - no logged errors - optimum start working fine on all zones etc. Happy to rebind (and will) but not sure what we should be looking out for as a fault to guide us ?

                            My suspicion is that it's calculated the heat loss curve for the room either incorrectly or strangely. Basically it's scared to let it drop down to the set point as it's not sure it can bring the temperature up quickly enough (essentially what Ramases is saying) - In this instance it would seem to me that the system should arrange a larger hysteresis loop for the temperate rather than quickly cycling the boiler every few minutes.....

                            what I'm I think I'm saying is I think this is a 'feature' not a fault.

                            decent logging would of course let us know
                            From my experience one of the main 'things' I come across is when you are binding HR92's to the evohome controller.

                            Sometimes the binding menu will 'jump' when the first HR92 is bound and instead of asking you if you would like to bind another HR92 to the same zone, it will say straight away on screen 'bind actuator to zone' and most people will then rebind the same HR92 they have already bound. I am not sure on the consequence of this happening, but I believe this can cause issues. This seems to happen when you click the 'bind signal received properly' green tick box too quickly after you bind the first HR92 (i.e. not giving enough time for the evohome controller and HR92 to sync properly).

                            I personally know 100% how the binding procedure should unfold correctly and I know how to clear the binding on all evohome items 100% correctly before rebinding. Most people 'think' they know how to bind/unbind evohome, but they don't because they have never bound more than one evohome system and they are assuming things are bound correctly, when potentially they have made the mistake and then blame the equipment for their lack of understanding.

                            Installation errors are also too common a fault... How many times have I heard from a customer, 'Yes, of course everything is installed correctly' and as soon as I ask for photos, the excuses start or I get the photos off the customer and blatantly the HR92 is behind a curtain or the BDR91 Wireless Relay Box is in a metal clad room!

                            End of the day, all of the installations I have performed personally have been error free installations and all the people I have talked through a bind procedure will normally turn around and say 'well it didn't do that last time I bound it'.

                            I don't have to help technically (no other supplier of evohome does) but I genuinely love the product and I am here to help my evohome customers gain full benefit from the system should they choose to do the installation themselves. Last thing I want is a great system to be written off over forums unjustly.

                            If you don't want my help no problem at all, but I am at the end of the phone should you change your mind.
                            Last edited by The EVOHOME Shop; 10 February 2015, 03:45 PM. Reason: bad spelling

                            Comment

                            • HenGus
                              Automated Home Legend
                              • May 2014
                              • 1001

                              #15
                              Originally posted by The EVOHOME Shop View Post

                              Installation errors are also too common a fault...

                              I don't have to help technically (no other supplier of evohome does) but I genuinely love the product and I am here to help my evohome customers gain full benefit from the system should they choose to do the installation themselves. Last thing I want is a great system to be written off over forums unjustly.
                              Richard - you are of course correct but not all installers have your knowledge or passion. Unless a component is faulty, self-installers have only themselves to blame if the installed system has issues. Those who choose to have a professional installation carried out under the Honeywell Installer scheme should not have to delve into installation instructions to find out what might be wrong. In my case, the team at Honeywell have offered excellent advice and given it freely; however, if Honeywell want this product to be a success then it needs its installer network to share your enthusiasm.

                              Comment

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