Forum Discussion

DazedNConfused's avatar
DazedNConfused
Explorer
Nov 05, 2013

Bad thermostat?

Was camping over the weekend and temps got down into the upper 30s. Fired up the furnace in the morning to take the chill out and both the furance AND the A/C came on at the same time. Huh. Odd. I set the thermostat to all off which shut down the A/C...followed by the furance a minute or so later. Waited abut 5 minutes, chose heat again from the thermostat, and the same thing happened -- both heat and A/C. So I shut off the A/C at the breaker panel and let the furnace run figuring I'll deal with it when I got home. Haven't tried it since being home...but wondering if others have seen this.

Thanks,
- DNC

16 Replies

  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Nov 08, 2013
    avvidclif1 wrote:
    The first time I used the heater in my new trailer it had very low air volume. Thinking it might have the blower on low I changed the thermostat from Auto to High and the fan in the AC came on, the heater never changed. Put it back on Auto and the AC fan shut off. Turns out the heater had a duct problem. I still don't know why the AC fan would come on when the heater is on. Just one of those things that keeps me scratching my head in wonder at the design engineers for the different RV systems.


    avvidclifl wrote:
    This is an "all in one thermostat" controls heat and up to 4 AC's. Not separate controls for heat and AC


    In your post you changed from Auto to High and A/C unit Fan came ON.
    That is because the Fan Mode controls the A/C Unit Fan. It does not control the furnace fan. The furnace fan/blower is part of the furnace and only runs when HEAT is called for.

    The A/C Unit Fan running with Furnace (Fan Mode NOT in Auto) is to help circulate the indoor air so that the heat from furnace is circulated thru out the RV helping to more the warm air around.

    The A/C unit Fan can also be turned ON by itself to just circulate air thru out RV with out A/C Unit OR Furnace ON.

    avvidclifl wrote:
    I give up.


    Don't give up.....
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Nov 08, 2013
    avvidclif1 wrote:
    Old-Biscuit wrote:
    Fan switch......
    Auto---only comes on if cool and A/C is selected
    ON--turns on A/C unit fan blower
    OFF---A/C fan won't run

    Furnace is strictly turned on via thermostat. The furnace is completely controlled from thermostat in HEAT mode

    The 'FAN' is the A/C blower.....nothing to do with furnace


    This is an "all in one thermostat" controls heat and up to 4 AC's. Not separate controls for heat and AC.


    OK......even simple thermostats that control heat & cool work the same
    In 'Auto' fan will only come on if A/C unit is selected
    If in 'HI' or 'LO' mode A/C unit blower will come on when furnace is selected

    The FAN is the A/C unit blower...furnace is still controlled separately from the thermostat
  • avvidclif1's avatar
    avvidclif1
    Explorer
    Nov 07, 2013
    Old-Biscuit wrote:
    Fan switch......
    Auto---only comes on if cool and A/C is selected
    ON--turns on A/C unit fan blower
    OFF---A/C fan won't run

    Furnace is strictly turned on via thermostat. The furnace is completely controlled from thermostat in HEAT mode

    The 'FAN' is the A/C blower.....nothing to do with furnace


    This is an "all in one thermostat" controls heat and up to 4 AC's. Not separate controls for heat and AC.
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Nov 07, 2013
    Fan switch......
    Auto---only comes on if cool and A/C is selected
    ON--turns on A/C unit fan blower
    OFF---A/C fan won't run

    Furnace is strictly turned on via thermostat. The furnace is completely controlled from thermostat in HEAT mode

    The 'FAN' is the A/C blower.....nothing to do with furnace
  • DazedNConfused's avatar
    DazedNConfused
    Explorer
    Nov 07, 2013
    golf_bears wrote:
    I trust he was "favorably aromatic"


    Oh, yeah...like a bloody bouquet of roses! :)

    -DNC
  • DazedNConfused's avatar
    DazedNConfused
    Explorer
    Nov 07, 2013
    golf_bears wrote:
    It actually makes sense. Heat rises and having the AC fan on helps move the hot air off the ceiling down towards the floor as well as moves hot air around the inside of the RV.


    I camped with some old childhood friends last weekend and we spent some time inside when it was raining. One of them in particular had no problem "moving hot air around the inside of the RV". In this case, keeping that "hot air" trapped up around the ceiling was a good thing! :)

    -DNC
  • DazedNConfused's avatar
    DazedNConfused
    Explorer
    Nov 07, 2013
    avvidclif1 wrote:
    golf_bears wrote:
    It actually makes sense. Heat rises and having the AC fan on helps move the hot air off the ceiling down towards the floor as well as moves hot air around the inside of the RV.


    That's what the ceiling fan is for. Down in summer and up in winter.


    Not everyone has a ceiling fan. Mine does...but I could still see how this feature could be useful -- especially in campers without a ceiling fan.

    -DNC
  • avvidclif1's avatar
    avvidclif1
    Explorer
    Nov 07, 2013
    golf_bears wrote:
    It actually makes sense. Heat rises and having the AC fan on helps move the hot air off the ceiling down towards the floor as well as moves hot air around the inside of the RV.


    That's what the ceiling fan is for. Down in summer and up in winter.

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