Results 1 to 9 of 9
  1. #1
    Join Date
    Feb 2003
    Posts
    5

    Honeywell RTH8500 THermo - How to make backlit stay always on?

    I have a new RTH8500. Can I make the backlit stay always on? If so, how?
    Thanks

  2. #2
    Join Date
    May 2007
    Location
    DC Metro Area (MD)
    Posts
    3,368
    Do you have 24v coming into the thermostat or are you using a battery? It may be in the installer setup options like the VisionPRO.

  3. #3
    Join Date
    Mar 2004
    Location
    Grottoes VA
    Posts
    5,856
    You have the cheap version of that t-stat. It does not include that option. If you really want that feature then you need to call a HVAC contractor to install the real Vision Pro.
    Karst means cave. So, I search for caves.

  4. #4
    Join Date
    Feb 2003
    Posts
    5
    I have 24V coming to thermostat and also have 3 batteries.

  5. #5
    Join Date
    May 2007
    Location
    DC Metro Area (MD)
    Posts
    3,368
    Karsthuntr may be right. It may or may not be in the installer setup. If you want a backlight to be lit up always, then you may need to have a VisionPRO installed.

  6. #6
    Join Date
    Feb 2003
    Posts
    5
    Thanks both. Is the VisionPro 8000 compatible with 24V system? Also, Honeywell lists various model #s for VisionPro 8000. What is significance of Model #s?

    Model Numbers: TH8110U1003, TH8320U1008, and TH8321U1006, TH8110U1011, TH8320U1016 and TH8321U1014

  7. #7
    Join Date
    May 2007
    Location
    DC Metro Area (MD)
    Posts
    3,368
    What kind of system do you have? Gas heat with A/C, heat pump, etc.

    I'd go with the TH8320U1008 if you don't want any humidity control by overcooling (TH8321U10**).

  8. #8
    Join Date
    Jun 2006
    Location
    Hastings, MN
    Posts
    417
    Do not try to buy this and install it your self. You will need to call a hvac company to install and match it to your hvac system. I have been out on way too many HO installed and all screwed up.
    Aint Notin Sweeter, Then A Brand New Heater!!!!!!!!!!

  9. #9
    Join Date
    Feb 2003
    Posts
    5
    I have 1 Gas furnace & 1 AC system.

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