Evohome Single Zone Not Working

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  • DBMandrake
    Automated Home Legend
    • Sep 2014
    • 2361

    #16
    Originally posted by f1arp72 View Post
    What, leaving it in the unlocked position ? If it's unlocked on a desk, it's doesn't do the cycled and set the valve closed. I'll give it a try, but pretty sure when I had mine unlocked off the Rad, it didn't do anything but maybe I'm wrong.
    It won't call for heat if the latch is open, but you can close the latch without putting it on the radiator, then it should work.

    If it still doesn't work it might be because it can't calibrate the valve position when the valve wheel is not attached - it will try to wind the valve closed (CYCLE mode) but there is nothing to limit the rotation when it's not attached to the valve wheel - so the calibrate process will fail. I'm not sure if that will cause it to be unable to call for heat but if you want to be really certain, unscrew the white and black base off your radiator as well and fit it to the HR92 then close the latch and wait for CYCLE to finish.

    Now it will most definitely be able to calibrate and will be able to call for heat. Now you can walk with it further into your house and adjust the manual override wheel on the top to see if it calls for heat!

    The best most conclusive way to do this is set all of your other zones to a 5 degree override and hot water off (if applicable) and give that a few minutes to take effect so that there is no other demand and the boiler relay is off, then alternatively turn the HR92 you are carrying right down to 5 and right up to 30. Remember it takes up to 30 seconds for the motor to turn the valve head from one extreme to the other, and it waits until after it finishes turning before it sends a new wireless heat demand.

    So turn the temperature to one extreme and wait for the motor to stop turning before deciding whether it worked or not. You should be able to bring the boiler relay on by turning it right up and off by turning it right down. If that works when you are in the house but not when you are in the conservatory it must be a signal issue! If it still doesn't work when you're near the Evotouch then there is some sort of binding issue or possibly even a hardware fault.

    In that case I would try a reboot of the HR92 first and then the controller if still not working. I have occasionally had to reboot an HR92 by removing the batteries due to odd behaviour.
    Last edited by DBMandrake; 3 November 2016, 01:50 PM.

    Comment

    • Nicodemus
      Automated Home Lurker
      • Nov 2016
      • 7

      #17
      Hi, I have only recently installed Evohome, so not an expert. But I have spent about 25 years diagnosing bugs in computer systems. In that time I have learnt (1) not to take anything for granted (2) narrow down a problem systematically by only changing one thing at a time.

      So I apologise if I have got this wrong, but I have noticed that several times you say "the boiler does not fire" without actually saying you have checked the boiler. What you seem to mean is "the radiator does not get hot". These are not the same thing. The boiler not firing is only one possible explanation of the radiator not getting hot.

      You have said that the HR92 from the conservatory works ok on another radiator. You have also said that the signal strength in the conservatory is 5.
      So it's hard to see how the HR92 is the problem.
      It seems to me the symptoms you describe are most likely caused by the TRV pin sticking in the closed position. (Even if I am wrong it's worth eliminating from your investigation).

      A TRV valve body has a pin that can move up and down about 2mm. Down is closed. Up is open. It is pushed open by a spring. It is held closed (or released to open) by the head (whether a trad TRV or a motorised one like HR92). If it is sticking the HR92 will try to release the pin, but the pin will stay closed. Then obviously the radiator will not get warm. The easiest way to test this is to remove the HR92 entirely - so the pin should be fully open.
      Then turn up the temp at any other zone. This will fire up the boiler. In this scenario the other zone's radiator should warm up. AND so should the one in your conservatory. If not, there is something wrong with the rad - not the HR92.

      Also this would probably explain your boiler occasionally overheating and locking out. If the conservatory HR92 "thinks" it is open and fires the boiler, but actually the valve is stuck closed.

      If your conservatory rad does heat up when other zones call for heat, then I am wrong, but at least that's one problem eliminated!

      Comment

      • Nicodemus
        Automated Home Lurker
        • Nov 2016
        • 7

        #18
        On a more general note, I think anyone with a problem should check certain basics before assuming the problem must lie with Evohome.
        E.G balancing your radiators is important whether you have manual wheel-heads, standard TRV's or HR92's.

        Comment

        • sidepipe
          Automated Home Jr Member
          • Oct 2015
          • 18

          #19
          I know this is a very old thread, but I think it's just as relevant today. I've had this issue, and never been able to track it down. I believe it to be a bug in EvoHome ( a pretty serious one really ) - or, some strange operation parameter that is counter-intuitive. The evidence was always there and pretty obvious really ( at least in my case. ) The zone in question has a DT92 detecting the temperature, and a HR92 on a single rad. The boiler isn't fired up when the zone should be calling for heat, so unless another zone needs heating nothing happens, heat wise. The salient points are:
          • Comms test for both the HR92 and DT92 are fine, but anyway....
          • Turning the temperature control on the HR92 changes the setting on the controller
          • Changing the temperature on the DT92 changes the temperature on the controller... so....
          • Whatever the case with the other hardware, the controller KNOWS there should be demand for heat, and...
          • I know the controller can control the BDR91 for other zones.


          So given this, then assuming the controller is what "decides" when the boiler should be firing up, and I know the hardware works, there must be a problem with the software in the controller.

          Now there's info on the boiler demand for each zone, surely these two pictures summarise the fact:

          20181109_095733.jpg
          20181109_095748.jpg

          The controller knows the temperature is currently 18 degrees. The controller knows the zone temperature requested is 30 degrees. The zone heat demand should surely be 100%, but is actually 11%. Ergo, software problem. Or am I missing something obvious here???

          Comment

          • Stevedh
            Automated Home Guru
            • Mar 2017
            • 177

            #20
            Depends... what target temperature is showing in the HR92?

            Comment

            • Stevedh
              Automated Home Guru
              • Mar 2017
              • 177

              #21
              Ok probably should have read that properly.. assuming you got 30 degrees but turning the dial on the HR92.. then does sound like a bug.

              Comment

              • sidepipe
                Automated Home Jr Member
                • Oct 2015
                • 18

                #22
                Originally posted by Stevedh View Post
                Depends... what target temperature is showing in the HR92?
                Um... 30 degrees.... but in any event why would that matter given the fact the controller knows the target temp, and that it's the controller that decides on heat demand for the boiler NOT the TRV? It's possible the TRV sets its position based on its idea of target temp, and that it then reports its idea of heat demand back to the controller, but as a design principle that wouldn't make much sense. It's far more likely the controller tells the TRV what position it should be in. But anyway, as I say, the TRV's showing the correct target so it's all pretty moot.

                As a further test, I used the TRV to turn the zone off... the controller reported 0% demand, so at least it got that right... the TRV also closed, so that bit worked. I then turned the temp up to 35 degrees on the TRV. The valve opened - by the sound of it quite a way ( if not 100%, obviously I've no real way of knowing how far, but the motor ran for a good few seconds. ) Controller now shows 35 degrees target. Heat demand for the zone is........... 4%.

                Edit: I've opened a case with Honeywell. I'm sure I'll get the normal dumb standard responses you tend to get from support desks but I'll update the thread if I get anywhere sensible.
                Last edited by sidepipe; 9 November 2018, 12:52 PM.

                Comment

                • SensibleHeatUK
                  Moderator
                  • Feb 2009
                  • 228

                  #23
                  Originally posted by sidepipe View Post
                  Um... 30 degrees.... but in any event why would that matter given the fact the controller knows the target temp, and that it's the controller that decides on heat demand for the boiler NOT the TRV? It's possible the TRV sets its position based on its idea of target temp, and that it then reports its idea of heat demand back to the controller, but as a design principle that wouldn't make much sense. It's far more likely the controller tells the TRV what position it should be in. But anyway, as I say, the TRV's showing the correct target so it's all pretty moot.

                  As a further test, I used the TRV to turn the zone off... the controller reported 0% demand, so at least it got that right... the TRV also closed, so that bit worked. I then turned the temp up to 35 degrees on the TRV. The valve opened - by the sound of it quite a way ( if not 100%, obviously I've no real way of knowing how far, but the motor ran for a good few seconds. ) Controller now shows 35 degrees target. Heat demand for the zone is........... 4%.

                  Edit: I've opened a case with Honeywell. I'm sure I'll get the normal dumb standard responses you tend to get from support desks but I'll update the thread if I get anywhere sensible.
                  The Radiator Controller actually does all the control locally, and has to report back its demand to the touchscreen, which in turn collates demands from all zones and sends this on to the boiler controlller.

                  The Radiator Controller only syncs with the touchscreen roughly once every 5 minutes, so you need to leave enough time for all the messages to pass through the system. So making a setpoint change from a room sensor or touchscreen unit can take upto 5 minutes before it gets picked up at the Radiator Controller, then you have to wait for the Radiator Controller to react and pass it’s demand back to the touchscreen before it signals the BDR to react. The system has worked this way for more than 15 years, and the devices need to maintain backward compatibility with these legacy devices, so I doubt it will change any time soon.

                  So maybe you simply need to give the system time to react to your changes?
                  Sensible Heat
                  SensibleHeat.co.uk

                  Comment

                  • sidepipe
                    Automated Home Jr Member
                    • Oct 2015
                    • 18

                    #24
                    Originally posted by SensibleHeatUK View Post
                    The Radiator Controller actually does all the control locally, and has to report back its demand to the touchscreen, which in turn collates demands from all zones and sends this on to the boiler controlller.

                    The Radiator Controller only syncs with the touchscreen roughly once every 5 minutes, so you need to leave enough time for all the messages to pass through the system. So making a setpoint change from a room sensor or touchscreen unit can take upto 5 minutes before it gets picked up at the Radiator Controller, then you have to wait for the Radiator Controller to react and pass it’s demand back to the touchscreen before it signals the BDR to react. The system has worked this way for more than 15 years, and the devices need to maintain backward compatibility with these legacy devices, so I doubt it will change any time soon.

                    So maybe you simply need to give the system time to react to your changes?
                    Nope, left it for ages. However, if the TRV actually does control things locally, then it could be the TRV not telling the controller its demand.

                    Thing is ( and I'm not doubting what you say as such because you sound like you know what you're talking about, I'm just curious, ) that doesn't make a lot of sense for a number of reasons. Chiefly, if the HR92 isn't also acting as the temperature sensor as in this case, how would it even KNOW what it's demand should be, without being told by the controller? The TRV and radiator could be covered by a blanket and think the room's 30 degrees....... IF the control is all local, that would just mean having an external sensor is useless, surely?

                    Comment

                    • Stevedh
                      Automated Home Guru
                      • Mar 2017
                      • 177

                      #25
                      Interesting point I'd be interested in knowing the answer on how the HR92 works when paired with an external temperature sensor.
                      My guess for consistency is that the controller receives the temperature from the sensor then passes it on to the HR92 when then deciders whether or not to demand heat..hmm

                      Comment

                      • SensibleHeatUK
                        Moderator
                        • Feb 2009
                        • 228

                        #26
                        Originally posted by sidepipe View Post
                        Nope, left it for ages. However, if the TRV actually does control things locally, then it could be the TRV not telling the controller its demand.

                        Thing is ( and I'm not doubting what you say as such because you sound like you know what you're talking about, I'm just curious, ) that doesn't make a lot of sense for a number of reasons. Chiefly, if the HR92 isn't also acting as the temperature sensor as in this case, how would it even KNOW what it's demand should be, without being told by the controller? The TRV and radiator could be covered by a blanket and think the room's 30 degrees....... IF the control is all local, that would just mean having an external sensor is useless, surely?
                        The remote sensor sends its value to the touchscreen, and it in turn sends this value to the Radiator Controller (all comms go via the main unit in this case). So the Tadiator Controller receives updates around once every 5 mins from the controller. This is as much about extending battery life as anything else, only powering the radio transceiver for short periods every few minutes. Note that if you make a change at the Radiator Controller this can be sent immediately, it is only the receiving of messages by the Radiator Controller that is subject to the 5 minute polling interval.
                        Sensible Heat
                        SensibleHeat.co.uk

                        Comment

                        • sidepipe
                          Automated Home Jr Member
                          • Oct 2015
                          • 18

                          #27
                          Originally posted by SensibleHeatUK View Post
                          The Radiator Controller actually does all the control locally, and has to report back its demand to the touchscreen, which in turn collates demands from all zones and sends this on to the boiler controlller.

                          The Radiator Controller only syncs with the touchscreen roughly once every 5 minutes, so you need to leave enough time for all the messages to pass through the system. So making a setpoint change from a room sensor or touchscreen unit can take upto 5 minutes before it gets picked up at the Radiator Controller, then you have to wait for the Radiator Controller to react and pass it’s demand back to the touchscreen before it signals the BDR to react. The system has worked this way for more than 15 years, and the devices need to maintain backward compatibility with these legacy devices, so I doubt it will change any time soon.

                          So maybe you simply need to give the system time to react to your changes?
                          Quoting SensibleHeatUK again because I may have discovered something and it's their reply that pointed me at it....

                          I think the key was that the radiator valve tells the controller what its demand is... My guess is it's a little more complex than you said, as in the HR92 can receive information from the controller which it will use in addition to or instead of its own temperature sensor, so the controller tells the HR92 the zone temperature and it then uses THAT info to decide how open the valve should be. The HR92 then reports its position back to the controller. I don't KNOW this to be the case, but based on your info, observations, and a bit of logic, that would seem to be sensible. ( edit: I see you followed up saying as much... )

                          So, with that in mind, I got to thinking it was probably the HR92 not reporting the position correctly, or something similar. I disconnected the HR92, unscrewed the base from the TRV, and did a few experiments. Long story short, I now think the base is pushing the TRV pin some way down even when it's fully open, because it screws a long way down onto the TRV body. I tightened the HR92 base only until I could feel resistance from the pin, replaced the HR92 on its base, and voila - it now works.

                          I assume I missed something in the installer guide about this? ( Though to be fair to me it wasn't obvious - the additional pressure when screwing the base on was only slight. ) Surely there should've been some sort of error from the HR92 given that it knew it couldn't open fully?

                          The HR92 is now very loose on the TRV body, which doesn't seem right and will be prone to move in future I'd think - is this normal or is it just a quirk of this valve?

                          Anyway - hopefully problem at least worked around.... it's worth anyone else who's had similar issues double checking how the HR92 sits on the valve!
                          Last edited by sidepipe; 9 November 2018, 01:48 PM.

                          Comment

                          • DBMandrake
                            Automated Home Legend
                            • Sep 2014
                            • 2361

                            #28
                            Originally posted by sidepipe View Post
                            Quoting SensibleHeatUK again because I may have discovered something and it's their reply that pointed me at it....

                            I think the key was that the radiator valve tells the controller what its demand is... My guess is it's a little more complex than you said, as in the HR92 can receive information from the controller which it will use in addition to or instead of its own temperature sensor, so the controller tells the HR92 the zone temperature and it then uses THAT info to decide how open the valve should be. The HR92 then reports its position back to the controller. I don't KNOW this to be the case, but based on your info, observations, and a bit of logic, that would seem to be sensible. ( edit: I see you followed up saying as much... )
                            Sensible Heat's description of how it works is accurate, but here's a little more detail.

                            Processing of temperature measurements works like this:

                            Multi-room zone - every HR92 in the zone uses its own internal temperature sensor reading directly and adjusts its own radiator valve pin position to attempt to regulate the room to the target set point as measured at that HR92. The "primary" HR92 for the zone (the one you bind first) sends its measured temperature to the controller, but this is for display/informational purposes only. The temperature measurement of the other HR92's in the zone can only be seen on their own displays. Each HR92 in the zone also sends a heat demand to the controller which is based on the valve pin position, but it is a non-linear mapping that looks like the graph in the following post:



                            The controller takes the highest heat demand figure of all the HR92's within the zone and displays that as the heat demand for the zone in the diagnostics page. The highest heat demand of any zone is then forwarded onto the BDR91 or OpenTherm bridge to fire the boiler.

                            Single-room zone - similar to the above but with the following differences:

                            Only one temperature sensor for the zone. This could be an HR92 or a wall stat like a DTS92. In the case of an HR92 it's the first HR92 bound to the zone. Whatever the nominated sensor is, this sends the temperature reading to the controller which displays it, and also forwards it on to all HR92's in the zone every 4 minutes or so. As before, each HR92 makes adjustments to its own radiator to try to meet the set point and then sends heat demands back to the controller, which uses the highest heat demand of all the HR92's in the zone as described earlier.

                            There's a couple of quirks in single room zones which aren't immediately apparent. The first is that if you have a single room zone with a single HR92 in it which is also the temperature sensor - the most common situation, the HR92 doesn't actually use it's temperature sensor reading directly. (!) It periodically sends the measured temperature to the controller (frequency of updates depends on the rate of change of temperature) which then about every 4 minutes sends it back to the HR92. The HR92 only acts on this delayed, "re-transmitted" temperature reading coming back from the controller.

                            This can be proven by noting that if you rapidly heat or cool an HR92, the reading will change on the controller many minutes before the reading will change on the HR92, so that the reading on the HR92 always lags significantly behind even though it is the source of the temperature reading. Or that if you take the batteries out of the controller the temperature reading on the HR92 won't react to temperature changes at all until it eventually defaults back to standalone fallback mode. (Which takes about an hour)

                            The other quirk is that even if you use a remote sensor like a DTS92 for the zone, each HR92 still uses its built in sensor for the window open detection feature, and every HR92 in a zone has its own independent open window detection. (Something to keep in mind)

                            So, with that in mind, I got to thinking it was probably the HR92 not reporting the position correctly, or something similar. I disconnected the HR92, unscrewed the base from the TRV, and did a few experiments. Long story short, I now think the base is pushing the TRV pin some way down even when it's fully open, because it screws a long way down onto the TRV body. I tightened the HR92 base only until I could feel resistance from the pin, replaced the HR92 on its base, and voila - it now works.

                            I assume I missed something in the installer guide about this? ( Though to be fair to me it wasn't obvious - the additional pressure when screwing the base on was only slight. ) Surely there should've been some sort of error from the HR92 given that it knew it couldn't open fully?

                            The HR92 is now very loose on the TRV body, which doesn't seem right and will be prone to move in future I'd think - is this normal or is it just a quirk of this valve?

                            Anyway - hopefully problem at least worked around.... it's worth anyone else who's had similar issues double checking how the HR92 sits on the valve!
                            What you describe is not normal, you should be screwing the base fully onto the valve body after first turning the black wheel anti-clockwise - if you can't without it causing the valve body pin to be pushed down significantly, the valve body is not dimensionally compatible with the HR92 and will not work very well. You certainly don't want to be leaving it unscrewed as you have.

                            What kind of valve bodies do you have and do they directly fit the M30x1.5 base or are you using an adaptor ?

                            You might want to read the following thread where I had problems with even Honeywell's own Valencia valves compressing the pin just by screwing the base on:



                            I eventually worked around it by using Stroke 1 mode.
                            Last edited by DBMandrake; 9 November 2018, 07:19 PM.

                            Comment

                            • sidepipe
                              Automated Home Jr Member
                              • Oct 2015
                              • 18

                              #29
                              Originally posted by DBMandrake View Post
                              What you describe is not normal, you should be screwing the base fully onto the valve body after first turning the black wheel anti-clockwise - if you can't without it causing the valve body pin to be pushed down significantly, the valve body is not dimensionally compatible with the HR92 and will not work very well. You certainly don't want to be leaving it unscrewed as you have.

                              What kind of valve bodies do you have and do they directly fit the M30x1.5 base or are you using an adaptor ?

                              You might want to read the following thread where I had problems with even Honeywell's own Valencia valves compressing the pin just by screwing the base on:



                              I eventually worked around it by using Stroke 1 mode.
                              Not sure what make the valve body is to be honest, but the HR92 base fits directly without an adaptor. Thing is, it does seem to work perfectly how it is now as far as I can tell.... I'd thought of using some shims of some sort but would be lucky to find some that are a perfect fit. Another option would be a blob of superglue or something just to stop it from turning.

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