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  1. #1

    Confused Thermostat is off and unit cycles on

    I have a Goodman Heat/AC unit and when the thermostat is off (both fan and Heat/AC switches), the unit will cycle on for a few minute. The air blowing out of the vents is room temperature. It does it mostly a night when the outside and inside temps are most different. Any ideas other that ghosts? Thanks.

  2. #2
    Join Date
    Jan 2012
    Location
    Broomall, PA
    Posts
    440
    What type of thermostat do you have? Can you take a pic of the screen when this occurs? Also does this cycling occur after a call for heat? It's possible there's a thermostat/wiring issue, but need some more info

  3. #3

    Honeywell Thermostat

    Quote Originally Posted by STEVEusaPA View Post
    What type of thermostat do you have? Can you take a pic of the screen when this occurs? Also does this cycling occur after a call for heat? It's possible there's a thermostat/wiring issue, but need some more info
    It is a Honeywell seven day programmable thermostat. This is happening now, so no call for heat. The set up has is 10 years old, so it is not a wiring issue. I noticed this behavior around six months ago. I have disconnected the thermostat to see if it resolves the issue. Maybe a faulty thermostat (?). There is no change to the screen when this happens.

  4. #4
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    4,437
    Are you sure you don't have an aircycler hooked to your system?

  5. #5
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,669
    Quote Originally Posted by 54regcab View Post
    Are you sure you don't have an aircycler hooked to your system?
    The fan relay may be sticking

  6. #6
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    4,437
    Quote Originally Posted by jtrammel View Post
    The fan relay may be sticking
    Could be, but all the sticking relays I've seen will just keep the blower going after a cycle has completed. It's odd that the blower just starts by itself.

  7. #7
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,669
    Quote Originally Posted by 54regcab View Post
    Could be, but all the sticking relays I've seen will just keep the blower going after a cycle has completed. It's odd that the blower just starts by itself.
    I agree but something has to be going on, could be a bad circuit board or corroded batteries in tstat or just a bad tstat

  8. #8
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,669
    Quote Originally Posted by edslee View Post
    It is a Honeywell seven day programmable thermostat. This is happening now, so no call for heat. The set up has is 10 years old, so it is not a wiring issue. I noticed this behavior around six months ago. I have disconnected the thermostat to see if it resolves the issue. Maybe a faulty thermostat (?). There is no change to the screen when this happens.
    Have you ever changed the batteries in tstat?

  9. #9
    Join Date
    Jun 2005
    Location
    SW Wisconsin
    Posts
    5,025
    Well, the older heating furnace setups could & often did do that due to the fan cycling thermostat switch being in the plenum area & directly wired to the 120 volt power.
    That way it is totally independent of the thermostat & would recycle especially after a heating cycle; the room thermostat could be removed & the blower would still be able to recycle.

    Though of course, I don't know how your system is wired or sensors used...

    No, it's not ghosts...

  10. #10
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,586
    Is the unit in the attic.
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    How many times must one fix something before it is fixed?

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