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TZ45 Z-Wave Thermostat Temperature Differential


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I've looked on the Forums, but cannot find this problem from anyone else. My z-wave thermostat programs are working fine to set the setpoint, etc. The problem is that the thermostat is ignoring the fact that the temperature is colder than the setting and doesn't turn off. For example, the setpoint is at 75, but the room temperature is 71. Temperature in room is accurate. I've seen calibration procedures when room temperature isn't correct, but nothing when this happens. Any ideas?

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Hi Dean,


This seems to be a defective thermostat or it could be related to the dead-band. It's best to contact RCS.


With kind regards,


I reached out to RCS and they said I should follow up with the company that sold it to me. I'll contact Smarthome today.



Sent from my iPhone using Tapatalk

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I just thought of the fact that I should check the front half of the dual zone system. The thermostat that isn't turning off showed Idle on Heat/Cool State and the Fan as Off in ISY and on the thermostat display, however, there was still air blowing into that area of the house. I checked the front half of the dual zone and it was on and blowing air, as well. That now makes me think that it's not the thermostat, but the dual zone not switching off or blocking the air flow. I have our HVAC guys coming out tomorrow, so we'll see and I'll report back.

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Looks like the issue was indeed the dual zone dampers. They are spring operated and were not closing correctly. Therefore, when the main thermostat called for the AC to turn on, air went to the entire house. Its warmer in the main part of the house because of windows and therefore to cool the front part of the house, the AC stayed on longer. With the back side of the house being more shady, it made that part of the house stay much colder than the settings on the thermostat that controlled that end of the house.


The key here, for me, was not recognizing that the thermostat indicated OFF in all areas. No system, no fan, etc., which meant it had done its part. Once I realized that, I started looking for airflow and found the issue with the dual zone throwing cool air into the other area of the house. I was too focused on the thermostat or the program and forgot there were other "moving" parts.


Thanks for the help, this is always a great forum!

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