Heat and air conditioning

Discussion in 'Heating / Cooling Systems' started by vagov, Oct 12, 2020.

  1. vagov

    vagov Well-Known Member Gold Supporting Member

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    When I turn on my furnace, I get heat from the floor vents, and cool air from the roof vents. At the same time, any thoughts on what’s going on?
     
  2. neighbormike

    neighbormike Well-Known Member Gold Supporting Member

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    Dometic A/C and thermostat??
    With digital thermostat?
     
  3. vagov

    vagov Well-Known Member Gold Supporting Member

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    Yes.
     
  4. tenttrailer

    tenttrailer Art & Joyce - Columbus, O

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    John, I did not see this post. I sent you a message regarding this issue. I cut and pasted it.

    I was talking to someone with a rv about the strange thing you had going on with the furance runing and blowing air and the ac fan kicking in. He said he had the same issues years ago. Something to do with the design of the thermostat. On his stat he could set the ac to high, low or auto, now if he turn it to heat and had the ac fan set to high or low whenever the floor heat would run the ac fan would run.

    The technical support help said set the ac to auto and all will be fine. It was some type of known problem. So try turning off heat, go to ac and set the fan is auto, go back to heat and see if that solves it.
     
    Last edited: Oct 13, 2020
  5. Sjm9911

    Sjm9911 Well-Known Member Gold Supporting Member

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  6. generok

    generok Well-Known Member Gold Supporting Member

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    IS the fan in the roof mounted A/C unit also running when you feel the cold air from ceiling vents? If so, that's likely the control issue above.

    If not, I wonder if there is an obstruction in the heat air handling loop somewhere.
     
  7. vagov

    vagov Well-Known Member Gold Supporting Member

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    Yes. When. The ac is on, the blower fan. Blows cold air out the roof vents as it should. When the furnace is on, hot air is coming out of the floor vents as it should, however. Cool (not cold ) compressor is not on. , just fan motor. air is coming out the roof vents at the same time. I Think I may try changing out the thermostat. As I reading reviews. That they are basically junk, and go from there
     
  8. Sjm9911

    Sjm9911 Well-Known Member Gold Supporting Member

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    You could try jumping the t stat also, just hook up the heat wires. See if the ac fan comes on. Then you will know for sure if it is the problem.
     
  9. neighbormike

    neighbormike Well-Known Member Gold Supporting Member

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    Just been dealing with this issue. I thought thermostat but was told most likely bad control board... new board comes with new stat. Swapped out the board... all was well until I went camping and still heard the relays clicking (no 120 at the site). Installed the new stat - it was worse! Put old stat in and googled the hell out of this. Did this last weekend and seemed to work: make sure fan is set to “auto”. Turn a/c setting up as high as it will go, then select your heat setting. Hope this helps!
     
  10. neighbormike

    neighbormike Well-Known Member Gold Supporting Member

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    That won’t work with this 3-wire design unfortunately... there’s a +, -, and signal wire...
     
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  11. neighbormike

    neighbormike Well-Known Member Gold Supporting Member

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    I will add that apparently, there is no better t-stat that works with this system... if anyone knows different I am all ears!
     
  12. Clemens

    Clemens New Member

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    Perhaps just the fan is turning on to circulate the air? Is that a seperate gas furnace? I bough one of those rooftop heat-pumps by Gree and just love that thing.
     
  13. Alben

    Alben New Member

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    Set the Dometic thermostat fan mode to "Auto".
     
  14. vagov

    vagov Well-Known Member Gold Supporting Member

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    Ok. I Set the thermostat. To auto. And it seems to correct. The problem. Simple fix. Feel like I asked a stupid question. But appreciate the feedback. Thanks. Everyone for your help
     
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  15. Sjm9911

    Sjm9911 Well-Known Member Gold Supporting Member

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    Not a stupid question, its a stupid thermostat. [:D]
     
  16. neighbormike

    neighbormike Well-Known Member Gold Supporting Member

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    Not a stupid question! I have been using this thing for three seasons and it just started f’ing up. It is not a well designed system - a little Googling will show you.... and look at the reviews of the thermostat!
     
  17. neighbormike

    neighbormike Well-Known Member Gold Supporting Member

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    If the auto thing doesn’t work by itself, try (like I said) raising the A/C temp setting higher and then adjust the heat setting... I am still playing with this lol
     

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