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  1. #14
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,304
    Quote Originally Posted by thegov3 View Post
    Hmm? OK. I will try auto. Do you have a HP or A/C. Does it make a difference on the screen?
    I have A/C only with two stage variable speed furnace. and no, it don't make a difference on the screen. Do you have an outdoor sensor on the IAQ?

    What happens when you run the fan in ON, the cold wet coil warms up and the moister that was on the coil will be put back into the air.

    Like in your car, you run the A/C for a while, and then you turn off the a/c to vent only and notice the air blowing out of the dash vent is warm and humid?

  2. #15
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,897
    On your normal screen, it will say humidity. Weather in heating or cooling mode, or weather in humidifing or dehumidifing mode. But to set the set point for dehumidifing, you push the more button. Until it says dehumidify. If it never says that, then its not controling the blower.
    Your contractor may have the slow ramp up set up by the blowers dip switches.
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  3. #16
    Join Date
    May 2008
    Posts
    40
    Quote Originally Posted by beenthere View Post
    On your normal screen, it will say humidity. Weather in heating or cooling mode, or weather in humidifing or dehumidifing mode. But to set the set point for dehumidifing, you push the more button. Until it says dehumidify. If it never says that, then its not controling the blower.
    Your contractor may have the slow ramp up set up by the blowers dip switches.
    You guys are awesome. Great info. No mater what set point I try on the t-stat's humidity screen (min 10% - max 60%), I never get the word "dehumidifying" above the arrows, that screen or anywhere on the t-stat. It always says "humidifier".

    beenthere: what exactly do I tell my installer to get him to come out. He has already told me twice that it will never say "dehumidifying". And I am not sure telling him: "that some guy in the Internet said it would" will get him out. Is it a wiring problem in the IAQ module, the furnace control board, or the HP?

    mayguy: Yes, I have a outside sensor installed.

  4. #17
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,897
    Tell him you want it set up to cool to dehumidify.
    Tell him the IAQ has 3 options for dehumidification control, and they are:
    None, dehumidify with A/C, and whole house dehumidifier.
    If he doesn't believe you, he can call Honeywell tech support and they will tell him.

    Do you have your owners manual, read it, it will tell you about setting the dehumidify % settings. If you can't get into that screen, then he doesn't have it enabled in the installer set up.
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  5. #18
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,304
    Along with what Beenthere said, point out on the installer manual on page 10 FIG 4 or page 17, FIG 5 (depends what board you have) and ask him then why they say DS is for dehumidifcation?

    If they wire the DS to the IAQ, and follow the set up menu then you'll get the dehumidifcation.

  6. #19
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,304
    Also, page 56 shows it. and what needs to be done.

  7. #20
    Join Date
    May 2008
    Posts
    40
    I pulled off the IAQ module cover and noted that the wiring is not set up for variable speed blower dehumidification in low speed. It is wired for a non powered humidifier in those same slots (see attached image). I have an April Air 600 humdifier. I also attached Honeywell's IAQ wiring diagram for variable speed blower dehumidification in low speed. They are both wired to the same slots. Are these two options mutually exclusive? I have a call into the installer.
    Attached Images Attached Images   

  8. #21
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,897
    The humidifier, and the blower slow down don't use the same slots.

    I know because I installed enough of these already on systems with humidifiers and VS blowers that I wired to slow the blower down.

    Many techs find that diagram confusing, so you not understanding it is understandable.
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  9. #22
    Join Date
    May 2008
    Posts
    40
    Well...after a lengthy call with the installer’s boss, and lots of convincing that the my new Lennox variable speed blower furnace combined with my new Honeywell IAQ t-stat is designed to control humidity, they are sending a tech out to look at the wiring and system...next week. I even told them it shows the wiring diagram in the install manual and that, like beenthere says, it can be wired three different ways for dehumidification. My guess is they still don’t believe me……

    Not to offend anyone, but I am quickly earning that a company's "Première Dealer" and "NATE" certification doesn’t mean much. It all about the talent that shows up on install day.

  10. #23
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,897
    NATE, Premiere, Factory Authorized, Comfort Specialist, etc, etc. Is marketing.
    If it wasn't, they wouldn't put it on their websites, or brochures.

    NATE started with good intentions.

    Of course, you heard of that road to somewhere thats paved with good intentions.
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  11. #24
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,304
    Hopefuly the learn something out of this from you and do the next customer the right thing.

    Also they should read any notes on the wire diagram/install manual of jumpers that may need to be cut or added to get the blower profile that is needed.

  12. #25
    Join Date
    Aug 2007
    Posts
    45

    Related Questions

    Hello,

    After working with three different techs, the Company finally installed my IAQ thermostat. As best I can tell, it was wired okay, but I'm not sure...

    I've been through the set up several times, and I think the installer set up is correct, with the exception of CPH (I'm still not confident enough to mess with CPH settings).

    Here's the thing: How is the dehum function supposed to work? I have system set to Cool, fan in Auto, and for starters the dehum setting to 50%. Humidity at the stat has read as high as 56% and nothing has happened yet. I tried setting humidity to 45%, but still nothing.

    However when the stat calls for cooling the humidty drops quite well.

    I have a Train XL14i single stage heat pump, w/ Trane XV95 variable speed fan. No Humidifier installed yet. Outdoor sensor installed. I have the overcooling (droop?) set to 2*F, instead of 3*F.

    I'm wondering if there is something wired wrong, but if the stat was calling for dehumidify with A/C, wouldn't stat say cool-on?

    Thanks!

  13. #26
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,897
    The previous action of the stat must be a call for cooling, before the stat will use the A/C for dehumidification.
    If it was powered down(as it should have been to wire it) it will need to do a regular A/C call, before it will do dehumid calls.
    If your indoor temp is already at the droop set point, it won't cool to dehumid either.
    If you set the humidity to 50%, the humidity has to be 5% above set point befor it will do a dehumid call. I set them to 45%, so they call if the RH gets above 50%.

    Set your temp to call for cooling, after that cycle, it will cool to dehumidify.
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