Forum Discussion

clev's avatar
clev
Explorer
Aug 01, 2015

Thermostat upgrade help

I had a new 15k btu ac installed in 2012 and an analog thermostat was installed. I've ordered a new digital thermostat with control box, and according to Dometic, I have the correct one. However, the wiring is totally different. The current analog has ~7 individual wires attached to 7 individual screws but the new digital only has 3 posts: +, -, and common, and there is a slot for a ribbon cable beside the lcd display. I have instructions, but they are ambiguous, at best. Can/will anyone offer assistance in wiring this new unit?
  • clev's avatar
    clev
    Explorer
    Aug 01, 2015
    My searches have revealed installation of Honeywell thermostats which appear to be a lot nicer and more functional than the digital dometic. However, none of the installation guides refer to the control box. Is the old analog control box used with the Honeywell, or is the box deleted? Could someone give me a quick answer before I start installing the Dometic? Thanks.
  • clev's avatar
    clev
    Explorer
    Aug 01, 2015
    My searches have revealed installation of Honeywell thermostats which appear to be a lot nicer and more functional than the digital dometic. However, none of the installation guides refer to the control box. Is the old analog control box used with the Honeywell, or is the box deleted? Could someone give me a quick answer before I start installing the Dometic? Thanks.
  • clev's avatar
    clev
    Explorer
    Aug 01, 2015
    Smk, I really appreciate your help. I had printed out 2 different sets of instructions and nothing made very much sense. Your pics and instructions should allow me to install this tomorrow. If I hit a snag, will you be monitoring this site tomorrow?
  • time2roll's avatar
    time2roll
    Nomad
    Aug 01, 2015
    Yes. Also the hi/low A/C fan can be set automatic.
    Furnace unfortunately is just one speed.
  • clev's avatar
    clev
    Explorer
    Aug 01, 2015
    Will this be full function; fan, heat, and air with multiple speeds.
  • time2roll's avatar
    time2roll
    Nomad
    Aug 01, 2015
    Yes cut or disconnect the wires and splice to the new harness.

    Once the old box is out it all starts to fall into place.
  • clev's avatar
    clev
    Explorer
    Aug 01, 2015
    Thanks smk; this is the same kit that I have.

    Paired white/black are 12v supply.
    Blue/white is control connection to furnace.
    Yellow is 120v power bundle.
    Black to the left is the freeze sensor.
    Brown is the bundle from the old thermostat.

    Does this imply that you 'spliced' the white and black, and, Blue and white wires'?
  • clev's avatar
    clev
    Explorer
    Aug 01, 2015
    Running new cables is not an option; I have to use what I have or keep the analog. I don't want to keep the analog. Also, there is no place to plug in a phone type cable; all I have is what is mentioned above.
  • newman_fulltime's avatar
    newman_fulltime
    Explorer II
    Aug 01, 2015
    you need the right cable its like a phone cable.You would be better off buying a 20/00 one from Walmart and putting in

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