UFH - EvoHome and reluctant plumber

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  • bruce_miranda
    Automated Home Legend
    • Jul 2014
    • 2307

    #61
    Understood, I am really hoping that the manifold TRV now serves as a fail safe, rather than my only defence against 65C water being pumped round my ufh, in case something happens to the TRV. I say that only because it has happened. When we first installed the UFH, the TRV was faulty and I heard cracking noises coming from the newly laid floor. I don't even want to know what damage that might have caused.

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    • kevinsmart
      Automated Home Ninja
      • Sep 2018
      • 257

      #62
      Originally posted by bruce_miranda View Post
      Understood, I am really hoping that the manifold TRV now serves as a fail safe, rather than my only defence against 65C water being pumped round my ufh, in case something happens to the TRV. I say that only because it has happened. When we first installed the UFH, the TRV was faulty and I heard cracking noises coming from the newly laid floor. I don't even want to know what damage that might have caused.
      In my new house, almost completed install, I’ve ditched the TMV and fitting a limit thermostat as a safety device.

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      • bruce_miranda
        Automated Home Legend
        • Jul 2014
        • 2307

        #63
        @kevinsmart what's the trick to get the HM80 bound with the WiFi Evohome controller? I have simply connected power to the HM80. It comes on with Led 2 Green , Led 3 Green and Led 4 Red Flashing. When I hold down both buttons for more than 4 seconds, there is no difference in the flashing pattern of the Led 4. When I send the Bind signal from the Evohome controller for a Mixing Valve zone, that Led 4 doesn't stop flashing.

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        • bruce_miranda
          Automated Home Legend
          • Jul 2014
          • 2307

          #64
          OK I think I figured it out. It didn't quite work when I held both buttons down at the same time. But if I pressed the Close button first held it down and then the Open button and then held them both down the LED 4 blinking frequency changed and then I knew I was getting somewhere. Then sent a Bind command and the LED 4 went off. Which means that it has bound.
          The tip is to make sure that the None of the LEDs are lit while you are trying to get the HM80 into Binding mode.
          Last edited by bruce_miranda; 20 January 2021, 05:38 PM.

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          • bruce_miranda
            Automated Home Legend
            • Jul 2014
            • 2307

            #65
            I realise this is an old thread but I just got my plumber to put in a 2 port rotary valve as linked to earlier. I left the 2 port motorised zone valve in place too, just in case, but it's now wired to open using the HM80 pump output along with the UFH pump.
            After all the connections were made I didn't quite understand why the HM80 was running the pump non stop. Turns out, I had set the Min Flow Temp too high and because the HM80's temperature sensor was detecting the Flow temperature too low (as the boiler was off).
            Now I have set the Max Flow temperature on the HM80 to 35C, Min Flow temperature to 10C. The manual TRV on my UFH manifold has been set to 40C, which just serves as a fail safe. In normal operation the TRV should be completely open as the Hot water coming into the manifold is colder than what the TRV has been set to. Pump over run has been set to 10mins. Now to see if this makes the UFH work better.
            All this to avoid TPI that is built into the BDR91!
            There are easier ways to do this. Use a delay pump overrun timer, so that even if the BDR91 closes the motorised zone valve, the UFH pump continues to run and hopefully bridge the TPI intervals.
            Or a software solution is to detect any Heat Demand of less than 100% being sent to the UFH BDR91 and replace that with a 100% Heat Demand. There is no TPI on 100% Heat Demand, by definition.
            Last edited by bruce_miranda; 14 September 2021, 10:12 PM.

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            • kevinsmart
              Automated Home Ninja
              • Sep 2018
              • 257

              #66
              You should see better zone temperature control with the HM80, if that was previously a problem for you?

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              • bruce_miranda
                Automated Home Legend
                • Jul 2014
                • 2307

                #67
                My UFH heating pump is the Adaptive ramp up version, and the TPI from the BDR91 was making for quite an inefficient system. The pump was almost constantly ramping up, having been abruptly shut down between the TPI cycles. Let's see how things change now with the HM80. The scary bit for me is running listen only RF devices. There is absolutely no way I can tell if the HM80 has heard what it's supposed to and then react. I just have to trust that it did. Likewise, there is no way for the Controller to know if the HM80 goes dead.

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                • bruce_miranda
                  Automated Home Legend
                  • Jul 2014
                  • 2307

                  #68
                  Originally posted by kevinsmart View Post
                  You should see better zone temperature control with the HM80, if that was previously a problem for you?
                  @kevinsmart do you have a HM80 on a controller with the latest firmware? I have a strange issue where the actuator run time parameter keeps getting reset to 1sec. When I go in to change the setting, it shows 10secs, which is not what I set it to either.

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                  • kevinsmart
                    Automated Home Ninja
                    • Sep 2018
                    • 257

                    #69
                    Not now, I moved house and predominantly have HCE80s now. It was working fine with the latest firmware as far as I recall but I was just using the default run time setting, I only changed the max flow temperature.

                    Comment

                    • bruce_miranda
                      Automated Home Legend
                      • Jul 2014
                      • 2307

                      #70
                      This is definitely a bug. The actuator run time is getting over written by "something" and it goes back to 1 sec from the default value.

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