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camperdave's avatar
camperdave
Explorer
Aug 04, 2019

new thermostat install problem

I'm replacing the original RVP analog thermostat with a Honeywell. The old system had 6 wires which I believe to be as follows:

Red (+12v)
Blue (-12v)
Yellow (cooling)
White (heat)
Green (high fan)
Grey (low fan)

Based on some interneting, I thought I had it figured out. Capped the 12v+, Yellow to Y, White to W, Green/Grey combined to G, and Blue to R/Rc.

It did not work... Thermostat is calling for cooling, but AC is not coming on. Any help? :)

original thermostat:


New Honeywell:
  • BFL13's avatar
    BFL13
    Explorer II
    Aug 05, 2019
    Can't give you a complete proper answer, but my info from playing with thermostats is that:

    Blue is for the Hi-Fan, and Ground is black or green.

    On my furnace-only Honeywell, the two wires from the furnace go to W and R with R and RC bridged. I suspect your capped wire should go to R, but somebody will have to confirm.

    Yellow is for the cooling (don't have that in mine)

    Anyway, yes you probably have it wired wrongly.

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