Evohome Hot water problems

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  • bruce_miranda
    Automated Home Legend
    • Jul 2014
    • 2307

    #76
    I branched out the PSU used for the controller wall mount. Its rated at 4V 600ma. That voltage is too high, plenty of current. So passed this through an Ultra Low Noise 3V regulator and fed that to the CS92A with no batteries in it. For me this solution wasn't about making the comms of the CS92A more reliable, it was simply removing the need for batteries in it. And since I'm not using another PSU either, I'm quite pleased.

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    • G4RHL
      Automated Home Legend
      • Jan 2015
      • 1580

      #77
      Originally posted by bruce_miranda View Post
      I branched out the PSU used for the controller wall mount. Its rated at 4V 600ma. That voltage is too high, plenty of current. So passed this through an Ultra Low Noise 3V regulator and fed that to the CS92A with no batteries in it. For me this solution wasn't about making the comms of the CS92A more reliable, it was simply removing the need for batteries in it. And since I'm not using another PSU either, I'm quite pleased.
      Pleased you got power to it. As you have said it is odd for it to need its own batteries when there are so many devices nearby with power. I have two relays in the same cupboard (HW & CH) plus the three port valve and a power distribution box. A PSU built in somewhere to feed it would be a good approach. My control panel is downstairs so taking a feed from its supply and stepping it down is not really an option. A 3v PSU in the cupboard would be but I will stick to my lithiums for the present. Main reason being that my older boiler is going to need replacing at some stage and then hot water will from the one one direct. I keep saying my boiler will need replacing but it is over 22 years old and still works. Must spray some more silicon grease on the fan mechanism though to quieten it!

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      • bruce_miranda
        Automated Home Legend
        • Jul 2014
        • 2307

        #78
        The really bizarre thing is that the BDR91 itself, can be used to power the CS92A. The circuit inside the BDR91 is all using stepped down DC anyway. That would have been my alternative PSU. But in my case the BDR91s are quite far away from the actual cylinder. You can start seeing why Honeywell decided to make this battery powered, but I still think it could have allowed a mains powered route too, because unlike radiators and thermostats, the cylinder tends to have some power close by...or maybe Honeywell did foresee an installation where DHW cylinders didn't. e.g. No immersion heater and only a NTC sensor for a low powered bus.

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        • mtmcgavock
          Automated Home Legend
          • Mar 2017
          • 507

          #79
          Originally posted by bruce_miranda View Post
          The really bizarre thing is that the BDR91 itself, can be used to power the CS92A. The circuit inside the BDR91 is all using stepped down DC anyway. That would have been my alternative PSU. But in my case the BDR91s are quite far away from the actual cylinder. You can start seeing why Honeywell decided to make this battery powered, but I still think it could have allowed a mains powered route too, because unlike radiators and thermostats, the cylinder tends to have some power close by...or maybe Honeywell did foresee an installation where DHW cylinders didn't. e.g. No immersion heater and only a NTC sensor for a low powered bus.
          Ive used Evohome as a solution where it hasn’t been possible to get a wire to a cylinder cupboard with no power or easy route back to the boiler. Having said that it was probably easy to get a 240v supply there without the need to return to the main wiring box.

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          • bruce_miranda
            Automated Home Legend
            • Jul 2014
            • 2307

            #80
            That's what I mean, most cylinders will have some sort of mains power close to it, certainly as close as the CS92A sensor wire is. But like I said, Honeywell might have gone down the theoretical use case where a DHW cylinder has no unswitched power close by. e.g. My own Unvented cylinder doesn't even have an unswitched power immersion heater because I use my Solar Panels which switches on my immersion heater at the Mains Consumer Unit.

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            • filbert
              Automated Home Guru
              • Oct 2017
              • 161

              #81
              Originally posted by DBMandrake View Post
              I've set my Away to 10 degrees as well. Heating Off and Away have different use scenarios.

              Heating Off is for summer when you just want to completely turn off the heating schedule but still allow hot water. Since it's summer there's no chance of the house getting extremely cold 5C is OK as an off setting.

              Away mode is when you're away from the house, possibly for extended periods of time, and including winter.

              The default for Away is actually 15C not 5C, as far as I can remember ?


              I'm not guaranteeing that that's optimal for all installations - but on an installation where the system is having comms errors with the CS92A and other things have been checked it's certainly worth trying, even if it looks a little strange!
              Any update on this? The thread has gone quiet...

              Comment

              • filbert
                Automated Home Guru
                • Oct 2017
                • 161

                #82
                Can anyone tell me how I remove a CS92 transceiver? I think I need to move mine after a new towel rail was installed and the pipe is only about 6" away from it.
                It's quite low down and there's no obvious way to pop it of it's mount and I don't want to break it by poking in the wrong place.

                Comment

                • bruce_miranda
                  Automated Home Legend
                  • Jul 2014
                  • 2307

                  #83
                  I have been here before. I installed mine so close to the floor and with things in front that I had to break the backbox to get it out!
                  Behind the batteries there are two clips that need to be lifted together and I think there is another clip right at the bottom.

                  Comment

                  • filbert
                    Automated Home Guru
                    • Oct 2017
                    • 161

                    #84
                    Originally posted by bruce_miranda View Post
                    I have been here before. I installed mine so close to the floor and with things in front that I had to break the backbox to get it out!
                    Behind the batteries there are two clips that need to be lifted together and I think there is another clip right at the bottom.
                    Thanks, just two clips behind the batteries, as you said. Nothing at the bottom.

                    I've moved it so I'll be in to see if the hot water temp is more consistent. It's still a bit close to the tank (200mm) but I can't get it much further away without replacing the wire as it's a small airing cupboard. At least it's only 2m and 1 brick wall from the control box.
                    Last edited by filbert; 6 May 2020, 09:19 AM. Reason: Typos

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                    • bruce_miranda
                      Automated Home Legend
                      • Jul 2014
                      • 2307

                      #85
                      Oh and BTW my CS92A has been quite happily using my Evohome wall mount power supply put through a low noise 3.2V step down. One less set of batteries for me to worry about.

                      Comment

                      • M J
                        Automated Home Jr Member
                        • Jul 2021
                        • 18

                        #86
                        Originally posted by DBMandrake View Post
                        Touch wood I have had no comms errors since rotating it. (Whereas Lithium batteries alone didn't cure it)

                        Whether the polarisation helps may depend on the orientation of the CS92A relative to where the controller is - if the controller is perpendicular to the wall the CS92A is on horizontal polarisation may be fine, but in my case it's approximately 45 degrees to the left, so regardless of whether I fit it on that wall or the one at 90 degrees to the left of that, there is still a 45 degree angle to the controller.

                        So in this situation vertical polarisation which is omni-directional in the horizontal plane is going to be a better choice. In my particular case the signal increased by about 15dB by rotating it which is not insignificant.

                        If you do try turning yours 90 degrees I'd be interested to know if it helps. It can take a long time to tell for sure though as mine could still go for weeks without problems before... if it goes for a few months without comms errors or overshoots then I might consider it solved.
                        Hi a bit of a resurrection @DBMandrake I would be interested to know if you think the issue is now solved? I am looking to get a Hot Water CS92 added to my existing EvoHome and trying to see if it wil be stable enough, in my google search you seemed like you had a fair few issues.

                        Comment

                        • bruce_miranda
                          Automated Home Legend
                          • Jul 2014
                          • 2307

                          #87
                          It's a firmware bug, not a hardware bug. Get it, and learn to live the issues. It tends to work fine during an active heating cycle anyway.

                          Comment

                          • M J
                            Automated Home Jr Member
                            • Jul 2021
                            • 18

                            #88
                            Originally posted by bruce_miranda View Post
                            It's a firmware bug, not a hardware bug. Get it, and learn to live the issues. It tends to work fine during an active heating cycle anyway.
                            Hi Bruce thanks for the response, but it seemed that the advice DBMandrake was rotate the unit to improve the signal strength?

                            His last comment said he would consider case closed if it did not continue to have signal drop?

                            Can you explain why it is a firmware bug? Have I missed another thread?

                            Live with what issues?

                            "Tends to work" is not a glowing recommendation? I would be less than happy to fly on a plane that Tends to work... (Of course some Boeings tend to work now a days....)

                            Comment

                            • bruce_miranda
                              Automated Home Legend
                              • Jul 2014
                              • 2307

                              #89
                              We have investigated this issue to death. The HW sensor will transmit very rarely when it's not in an active heating cycle and thus the HW temperature is not changing frequently enough. Nothing you do to either controller or HW sensor positioning really helps. The controller just has to miss one message from the HW sensor and it reports it as a comms failure. And when the HW is not being heated the next message could be a good 12hours away.
                              But during the active HW heating times the sensor sends its messages very frequently and so the controller catches them, a missed message then is not so bad because the next message is just a few mins away. Not long enough for the controller to mark this as a comms failure. If you want reliability then Evohome isn't for you. The entire system runs on "hope" not "acknowledgement"

                              Comment

                              • M J
                                Automated Home Jr Member
                                • Jul 2021
                                • 18

                                #90
                                Originally posted by bruce_miranda View Post
                                The entire system runs on "hope" not "acknowledgement"
                                Sounds like a new marketing phrase for Evo Home?

                                OK thanks for the further explanation.

                                I will e-mail DBMandrake directly to see if he has thrown the unit away or he can live with it...

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