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Honeywell thermostat replacement

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nother_new_homeowner
nother_new_homeowner Member Posts: 6
in THE MAIN WALL
Hello all,

I replaced my old honeywell t87 mercury t-stat with a new ct87k heat only and now my heat seems to short cycle.

I set the dip switch to 2 on and left the first switch off as the chart indicated in the instructions for hot water heat.

Did I mess something up? Any help would be appreciated.

TIA

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Comments

  • Jamie Hall
    Jamie Hall Member Posts: 26,144
    Why did you replace the old thermostat? The old one worked much better than the new one...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    rick in AlaskaSuperTech
  • HVACNUT
    HVACNUT Member Posts: 6,834
    Try putting both dip switches on.
    A T5 might be a better option. Those T87 wannabes aren't the greatest. 
  • nother_new_homeowner
    nother_new_homeowner Member Posts: 6
    I replaced it because the room temp indicator was stuck on 72 degrees but the temp setting still worked ok.

    I went and looked in the box after my first post earlier and the temp indicator was back down to room temp, so I took a straw and blew out the 75 years worth of dust as best i could and just re-installed it.

    After looking around online it seems these are not indeed the best replacement for the old mercury activated ones.

    I will monitor the situation, and thanks for the suggestions...
  • Jamie Hall
    Jamie Hall Member Posts: 26,144
    For a situation where you don't need programming, there is no good substitute for the old mercury ones, in my opinion.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    MikeAmann
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 18,154
    I had those stats in my house and it started going wonky and I ripped it off the wall. They are flakey
    rick in Alaska

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