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Eyehi's avatar
Eyehi
Explorer
Jul 07, 2013

Digital thermostat

Hello everyone i was having a thermostat problem with my cougar 5 th wheel trailer last fall ( the furnace would not stop running) so i installed a digital thermostat..... The furnace worked great but my ac will not run.....would anyone have any advice on how to properly wire the thermostat so the ac will work ? The dometic thermostat was wired as follows
Red wire - 7.5
Yellow wire- cool
White wire -furnace
Blue wire - hi fan
Orange wire - fan
Black wire - ground

Here is the wiring on the new thermostat

Thanks in advance for the help
  • Eyehi's avatar
    Eyehi
    Explorer
    Jul 11, 2013
    Both systems are working great now.....the black wire did the trick....thanks for he advice!
  • Chris_Bryant's avatar
    Chris_Bryant
    Explorer II
    Jul 10, 2013
    Black and Orange together should give you low fan- black, orange and blue should give high fan- black orange blue and yellow hi cool, white and black furnace.
  • Eyehi's avatar
    Eyehi
    Explorer
    Jul 10, 2013
    Chris Bryant wrote:
    You must use a battery powered thermostat- if it needs power through the RC or RH connections, it will not work with the DuoTherm. The furnace does not hook to the thermostat- it is connected to the air conditioner.

    Thanks for the help chris.....the thermostat is battery powered i changed the batteries yesterday to make sure they were good.....the rep from lux corp had me touching wires together to check for power and nothing was working.....he said they usually check the fan motor because that is independent....
  • Chris_Bryant's avatar
    Chris_Bryant
    Explorer II
    Jul 09, 2013
    You must use a battery powered thermostat- if it needs power through the RC or RH connections, it will not work with the DuoTherm. The furnace does not hook to the thermostat- it is connected to the air conditioner.
  • Eyehi's avatar
    Eyehi
    Explorer
    Jul 09, 2013
    Spoke with a representative from the lux corp who makes the thermostat this morning.....there is no power going to the thermostat so i need to locate the fuse box going to the furnace and find out why there is no power.....i have found the fuse box but the fuses are all good....not sure where to check next ?
  • Eyehi's avatar
    Eyehi
    Explorer
    Jul 09, 2013
    Thanks for the replies guys i will try this tomorrow.....
  • Chris_Bryant's avatar
    Chris_Bryant
    Explorer II
    Jul 08, 2013
    The furnace should not be working the way you have it hooked up.
    DuoTherm switches the ground, so you need to disconnect the red wire and cap it, hook the black wire to RC and RH, hook up the tan wire to G (tan activates the fan relay, blue switches between hi and low). IOW- just like in downtheroad's diagram.
  • Eyehi's avatar
    Eyehi
    Explorer
    Jul 07, 2013
    Thanks for the help guys i tried a jumper wire and also switched the high fan wire with the low fan wire with no luck....scratching my head on this one ?

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