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  1. #1
    Join Date
    Oct 2006
    Posts
    34

    Honeywell Tstat 8320, etc questions

    I have the 8320 (model TH8320U/1008) tstat and have some question;

    1) The manual states to press the "System" key and then press the middle blank button to access the advanced settings. But there is no system key on the display. Another web site indicated to press and hold the two blank keys next to the middle key, but that does nothing also. Can someone confirm how to access the adv variable settings?

    2) What is the difference between the 8320 and the 8321?

    3) What about the IAQ differences? Is it significantly better?


    Side info: Tstat is connected to a duel fuel XL16i HP with a XV90 gas blower.

    Thanks

  2. #2
    Join Date
    Dec 2006
    Posts
    32

    Smile

    gerry,

    I have the 8321 unit that controls my all-electric home (heat pump w/elec. backup).

    1. The "system" key is to the left, under the fan key. On mine it reads HEAT right now. If I press the key, EM HEAT, HEAT, OFF and COOL APPEAR, and EM HEAT is blinking. IF I wanted to change the mode to COOL, for example, I would just press the system key 3 times, until COOL is blinking, and then initiate the command by pressing the DONE key at the bottom of the column.

    HOWEVER, to enter the setup routine, press DONE (to cancel any active commands), then press the system key once. You will notice the bottom row of keys go blank. NOW press and hold the two BLANK keys on either side of the center blank key, and after 3-4 seconds the advanced settings screen will appear.

    Before making any changes, it's a good idea to scroll thru and record the current settings. Unless you are fully aware of the workings of your system, you could do damage to the equipment.

    I know the board does not condone DIY; I happen to think that a knowlegeable homeowner should be able to make software changes.

    As far as differences between the 8320 and 8321, the 8321 has a built-in humidity sensor and displays the indoor humidity on the screen. I can set the unit to make the humidity setpoint dominate over the temperature setpoint while in cooling mode. However, under certain weather conditions, I come home and it's FREEZING inside. For MY purposes, I'm just not that pleased with this feature. I've been eyeing a whole house dehumidfier to solve that problem.

  3. #3
    Join Date
    Oct 2006
    Posts
    34
    Thanks Lackster, that worked. I was looking for the system key at the buttom and didn't even think to look at that side.

    I know this site is not for DIY, but I wouldn't think this would be considered a DIY question since it is referenced in the manual. I agree some minor software setting changes should be able to be performed by the homeowner.

    The reason I asked about the differences between the 8320 v 8321 v IAQ is because I currently have the 8320, connected to the trane config outlined previously and I wasn't happy with the dehumification ability and not sure if it is an issue with the Xl16i or the 8320. I had to lower my tstat temperature to get the house to be dehumified but ended up being a cooler setting. Some of the posting and other readings seemed to indicate the 8321 handled dehumification better. THe IAQ I'm just confused about.

    Buttom line, is the problem the XL16i or the tstat and if it's a limitation of the tstat then is it work replacing the 8320's with either 8321 or the IAQ?

  4. #4
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,305
    Quote Originally Posted by gerryh31 View Post

    2) What is the difference between the 8320 and the 8321?
    Only thing you gain with the 8321 is dehumidity control, but that only "Over cools" your home up to 3˚ to try bring down the humidity below the set point on the t-stat. it will not control the blower speed.

    3) What about the IAQ differences? Is it significantly better?
    By far better!!! I'd give this t-stat the "Thermostat of The Year Rewards".

    The IAQ is able to give you a full 4 stages of heat! Now, that is comfort.

    Here are the things that the IAQ can do than the 832x can't do.

    -4 stages in heat, no need to use the timer on your furnace for 2nd stage gas.

    -Able to control the blower for humidity control in the summer, and if the humidity is 5% over set point, then it will "over cool", but it don't happen often.

    -Can tie a whole house dehumidifier to it.

    -Can tie a HRV/ERV, or fresh air damper to it.

    -Tie a humidifier to it.

    -No need to fish new wires up tight or hard to reach area, only need 3 wires.

    -Can tie an outdoor sensor. The sensor can be used for a few things.
    • Control lock outs for heat pump
    • control lock out for gas back up
    • Control humidifer w/ use of "Frost Guard"
    • Or just to see what the temp is outside!


    I had the 8320 on my XV90 with my XR11 A/C. I went up to the IAQ last fall, and been happy with it.

    On mine, I have it doing this.
    • 2-Stage heating
    • A/C w/ Dehumidyt control by slowing down the blower.
    • Fresh Air damper to bring fresh air into the home
    • Humidifer Control

  5. #5
    Join Date
    Oct 2006
    Posts
    34
    Thanks Mayguy. Since the 8320 is about a year old, do you believe it's worth convert to the IAQ at this time?

  6. #6
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,305
    I had my 8320 for about a year, and sold it dirt cheap to my cousin. It will be worth the extra money..

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