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Hot Air Thermostat

billyL Member Posts: 3
My Brother-in-law bought an 20 year old hot air heated house. It has an AC evap. coil installed but no outside condenser. His thermostat has a fan only button but it doesn't work. Should it work without an condenser unit and might a new thermo help?


  • lchmb
    lchmb Member Posts: 2,997
    do you mean

    Are you trying to get the ac running? If so you need to complete the installation of the system. Sounds like someone put the coil in the plenum with plans to add ac and just never finished the job. You do need the condensor. You can however put a t-stat on that will control the blower on the unit if that's all you want..
  • Ironman
    Ironman Member Posts: 6,475
    Furnace Setup for A/C

    Check to see if the furnace has a "G" terminal on the low voltage terminal strip where the thermostat cable connects. It should be connected to the "G" terminal on the thermostat.

    If it's an older Lennox furnace, it may be labeled with an "F" terminal.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • billyL
    billyL Member Posts: 3
    Hot air Thwermostat

    Thanks Bob for you response I'll check for the green? wire at the thermostat and furnace next time I'm there.
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