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  1. #1
    Join Date
    Apr 2005
    Location
    Tampa, Florida
    Posts
    1,634
    Hi all,
    Just installed a Honeywell TH8321 (VisionPro multi-stage w/dehumidify) to replace an old T7300 I snagged from an office building before demolition (stat still works fine, just butt-ugly in a residential setting). Has anyone sat down & watched how it reacts to humidity? So far, it seems like it only will engage the first stage of cooling for dehumidifcation (good), but when I first installed it the room was at 81F/67%RH, with the dehumidify setpoint at 45%RH. Despite the wide difference between RH setpoint & actual, it didn't call for cooling. Later on in the evening, the stat had entered the evening (return) program, and indeed was running the first stage of cooling because of the humidity demand. Also, will it delay calling for stage 2 cooling if the latent load is high? While I'm asking q's, how does this stat determine when stage 2 is necessary? The WR 1F95-371 stat at my other residence seems to base it on the rate of temperature drop rather than a timer.

    So far, I like the VisionPRO...I thought the touch-screen would be gimmicky, esp. for a tech geek like myself, but it really is useful, as is the large display. Installer-programming menus stink compared to my WR, but the schedule programming more than makes up for it. It's only been installed for a few hrs, but so far the temp regulation seems good.

    Wish/gripe list:

    1) wish it had blue or amber backlighting (Hey Honeywell, you could charge more for this, and I'm sure the software could support switching different LEDs on/off...what the heck, put in RGB LEDs in and you could make the display any color you wish.)

    2) What's the deal with only 1 remote sensor? My WR supports 4 sensors (itself + 3 others) and can do time-of-day weighting for each. Cheaper to install (and eventual repair) than a true zoning system.

    3) Relays could be quieter, but I certainly will take the relay clicks over unreliable triacs.

  2. #2
    Join Date
    Apr 2005
    Posts
    13
    Try this number on Monday: 1-800-468-1502 tech hotline for professionals. They are really good.

  3. #3
    Join Date
    Dec 2001
    Location
    Ocean Pines, MD
    Posts
    6,983

    Droop

    With a DH call in cooling it will have a lower cut out temp the the setpoint.

  4. #4
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,914
    The dehumidify function won't overcool by more than 3, so if the room temperature is 3 or more below the temperature setpoint of the thermostat, it won't turn the system on to dehumidify.
    If more government is the answer, then it's a really stupid question.

  5. #5
    Join Date
    Apr 2005
    Location
    Tampa, Florida
    Posts
    1,634

    Finally got a chance to call Honeywell...

    Follow-up:

    Mark was correct... the stat needs the room temp to be within 3 deg of the setpoint for latent load to trigger a call for cooling. Additionally, if you're using a setback (which I am), the current program period temperature dictates this.

    Honeywell also confirmed that Adaptive Intelligent Recovery will not work if the DH feature is enabled, despite the menus allowing it. Instead, the stat will use a conventional recovery...Tech support was nice & friendly, but didn't have any additional info on this flaw.

    Regarding staging, not sure on if a DH call will delay stage 2 cooling engaging (sounds like it does, will keep an eye on the stat), but in normal cooling the stat uses an algorithm (sounds like P+I) to determine the need for stage 2. As to be expected, manual overrides to the program of a substantial difference from the current room temp will cause stage 2 to engage much faster than if the stat is running a program.


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