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  1. #1

    Honeywell TH800 Vision Pro Thermostat Help


    New to forum and to Hvac world, Just finished schooling a few weeks ago, and I am now working for company I did co-op with. So I have changed a few thermostats during co-op... but really not any digital ones...and they have all worked fine... except for this one.

    Heres the scenario... Changing an older mercury white - rogers
    t-stat to Honeywell TH 8000. White-Rogers pretty standard wiring
    Y-Black / W-White / G-Green / Rc & Rh - Jumper together from Red wire. PROBLEM is the new stat has R & Rc no Rh to start with... every thing else seems to be no problem.

    Rc and R come jumpered together on the new Honeywell TH8000.. so I used that for the Hot or Red wire from old T-Stat all seemed fine until I called for cool and the furnace came on at the same time as the a/c. I pulled the little jumper out and left wire in Rc called for cool no problem. Called for heat and nothing happened as expected. Put wire in R and called for heat it came on...called for cool nothing as expected. I then put R & Y together at T-[Stat and A/C unit came on no problem as expected. I then ran out of time as to what to troubleshoot next

    Luckily its a family friend, I had to leave for sons hockey... but am heading back there on Sat... any help as to what to do next with it would really be appreciated. The unit is brand new out of the package $179.00... so I am hoping its not the T-Stat. Sorry its so long winded... I am so green at this any help would be very much appreciated.

  2. #2
    Join Date
    Mar 2013
    Quote Originally Posted by smashedphish View Post
    Y-Black / W-White / G-Green / Rc & Rh - Jumper together from Red wire.
    You wired it correctly, just make sure the wires match on the furnace control board. Are you sure that they are both operating at the same time, and you're not just hearing the fan run? IF they are indeed running at the same time, make sure no copper wires are touching, and put fan on auto. If this still doesn't solve the problem, just jump y, and r / w, and r. If it works then I think it could be a bad stat.

  3. #3
    Thanks for the reply... really appreciate.

  4. #4
    Yes the furnace fires does fire up... A/C air gets pretty warm real quick.

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