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Solved! Setting Run vs Hold on Trane TZEMT400 Thermostat

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    Solved! Setting Run vs Hold on Trane TZEMT400 Thermostat

    This one has bugged me for many years… There's a hack to switch between ESM and Run/Hold, but the latter sets back to the most recently used of Run or Hold, whichever was most recently used; there's no way to force one or the other. If a user has set the thermostat locally to Hold, then that's where it stays.

    Inspired by jayph and his work deciphering the Trane XR524 (I didn't know you could read parameter values that way!), I went through all 255 Z-Wave parameters for one of my 5 Trane TZEMT400AB32MAA's, then again through the promising ones after changing from Run to Hold. Bingo – Parameter 132 it is! Sending a 1 sets the thermostat to Run; sending a 0 sets it to Hold.

    The event below instantly sets all my thermostats to Run mode. Conversely, sending a 0 to the same parameter sets them all to Hold.

    Click image for larger version

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    The old hack involved sending a 255 to the Temperature child device to set Run/Hold (whichever was last set locally at the thermostat), and a 0 for ESM. Bonus tip: Instead of using this hack, set ESM by sending a 2 to Parameter 25. This avoids the hack's side effect of having a 0 temperature reading until the temperature next changes.

    Given how many past treads there have been on this, thought I'd share this solution.

    #2
    Just tried this on my 2 XR524's. They both report 'ERROR' when trying to read parameter 132. I didn't try setting a value. It may be that different thermostat models support different parameter sets.

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      #3
      The parameter mapping seems to be unique to each thermostat model.

      Comment


        #4
        Click image for larger version  Name:	TZ45 HSTouch.JPG Views:	12 Size:	48.8 KB ID:	1418248
        TZEMT400BB32MAA's;
        Send 1 to Parameter 132, sets the thermostat to Run
        Send 2 to Parameter 25, sets the thermostat to ESM

        Works on early version 01.01.40 TZEMT400BB32MAA's
        but not version 02.02.15 TZEMT400BB32MAA's

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          #5
          TZEMT400BB32MAA v01.01.40 ID 0x5433
          Send 1 to Parameter 132, sets the thermostat to Run
          Send 2 to Parameter 25, sets the thermostat to ESM

          TZEMT400BB32MAA v02.02.15 ID 0x5436
          Send 0 to Parameter 40, sets the thermostat to Run
          Send 2 to Parameter 40, sets the thermostat to ESM

          (Notes - The TZEMT400BB32MAA v02.02.15 has an ID 0x5436, which is the same as the GC-TBZ48L thermostat, which has a list of parameters and values here;
          https://products.z-wavealliance.org/...s/2370/configs
          Tried parameter 40 for setback mode, and it works on the TZEMT400BB32MAA v02.02.15)


          Click image for larger version

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