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  1. #1
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    Honeywell IAQ Question

    I assume the thermostat is really a Honeywell IAQ since it shows it shows the humidity level (It is marked Trane). System is a Trane xl14i and the air handler is a variable speed. Very nice setup in my opinion.

    Question. Initially, the thermostat showed the humidity level only but did not allow you to change it. I read through the owner's manual and learned how to change the settings to allow the humidity level change. I enabled the option and now we are able to set the desired humidity level.

    Even though the original installers did not enable this option initially on the thermostat, do you think it was OK for me to enable the option? I assumed it would be since the air handler is a variable speed, but I just wanted to confirm this with the pros.

    Thanks for the help.

  2. #2
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    It won't hurt.
    But the question is, did they wire it so the IAQ(Trane900) can slow the fan.
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  3. #3
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    Quote Originally Posted by beenthere View Post
    It won't hurt.
    But the question is, did they wire it so the IAQ(Trane900) can slow the fan.
    Might be a TCONT803 (TH8321). I didn't think the 900 could work with non-communicating components ("C" models).

  4. #4
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    It can't, but he didn't say what AH he has.
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  5. #5
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    Quote Originally Posted by beenthere View Post
    It won't hurt.
    But the question is, did they wire it so the IAQ(Trane900) can slow the fan.
    Thanks beenthere! I just wanted to make sure that I wasn't going to damage the unit somehow by enabling the control of humidity level.

    The manual that the installer's left was for the TCONT800 (although I'm not sure what specific model it is 800, 802, or 803). The T-state does show the humidity level though, and since I have have enabled the option, it will attempt to control humidity.

    I'm not sure what the air handler is (although I can find out). This unit is at my parents house and was installed about a year ago. I just noticed on the air handler casing it said variable speed fan and is matched with the xl14i.

    I don't know if the thermostat is wired to slow the fan. Is there any way to tell without pulling the T-stat and looking at the wiring?

    By the way, what do you recommend as a good humidity level? I noticed the unit was reading 62% humidity. Is this good or bad?

  6. #6
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    The TCONT800 series can't slow the blower down for dehumidification. The TCONT803 can overcool by up to 3 degrees to dehumidifiy. 62% RH is on the high side. 50% is a good target. What's the thermostat's overcool setting for dehumidification?

  7. #7
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    Quote Originally Posted by RyanHughes View Post
    Might be a TCONT803 (TH8321). I didn't think the 900 could work with non-communicating components ("C" models).
    Ryan:

    It must be the TCON803. The T-Stat manual that the installer's left says "TCON800" (Although this covers models 800, 802, and 803) per Trane's website. It just seemed strage to me that the installer's did not enable the ability for the AH to control humidity via the variable speed fan. Although, I'm no HVAC expert by any means.

  8. #8
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    You might want to have the dealer back to make sure Comfort-R is setup (slow ramp profile in cool mode), CFM/ton is set correctly (airflow setting), and the thermostat is setup for dehumidification with that humidity reading. Do you have any other humidity meters? There have been some inaccurate humidity readings with that thermostat due to a various reasons. If there is a hole where the wires penetrate the wall behind the thermostat, it should be sealed.

  9. #9
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    Quote Originally Posted by RyanHughes View Post
    The TCONT800 series can't slow the blower down for dehumidification. The TCONT803 can overcool by up to 3 degrees to dehumidifiy. 62% RH is on the high side. 50% is a good target. What's the thermostat's overcool setting for dehumidification?
    I'm not sure what the overcool setting is set to (It should be the factory setting though). I will have to check. What do you recommend?

    Thanks for the humidity level info. This forum really is a wealth of knowledge.

  10. #10
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    Depends on how much humidity control you need and how much overcooling you want. The humidity level may be due to other issues, not the thermostat's settings.

  11. #11
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    62% is high.
    Have them double check that comfort r is enabled.
    If it cycles on and off on the hottest days, you may want them to set the blower to 350 CFM per ton.

    The RH should be less then 55%.
    You may wish to set the stat 45% and see if they feel more comfortable. After the contractor comes out and checks teh blower set up.
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