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enter image description hereenter image description hereenter image description hereenter image description hereI recently purchased a condo ( my first home ) which isn't new but mine. The prior owner left an Amazon smart thermostat but obviously didn't know how to wire the unit. I have the entire thermostat but remived the front to show the wiring. The unit has no control board I can see but two pigtails going through the low voltage area of the unit attached to the contractor. The unit is International Comfort Products # HAC024AKA5. I haven't touched the wiring so I'm asking here so I don't mess it up further. No power to the thermostat at all. I added some pictures in the hopes someone here can help me get it wired correctly and working. What i asking is what colored wires at the air conditioner get wired to the pigtails ? wiring diagram

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  • Can you post photos of the wiring at your inside unit (air handler) please? Commented May 3, 2022 at 3:46

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Given the wiring, it looks like you have the American bog-standard "forced-air furnace, with basic air conditioning unit bolted on" (in fact, an outdoor unit + an evaporator in the furnace air handling stack). The A/C uses the furnace's air handler to distribute the cool air. Everyone uses it because it's cheap. (to buy).

You are focused on the outdoor unit, which is just the air conditioner "hot-side unit" with the compressor and condenser. The rest of your system is indoors, and contains a gas (resistive electric?) furnace, with an air handler. This must be accessible because it has maintenance items, like the air filter.

However it doesn't really matter, because the 4 wires are just standard stuff.

  • R = 24 volt power supply
  • W = Furnace: call for heat (implied: call for fan)
  • G = Furnace: call for fan only (the A/C needs it to work)
  • Y = A/C unit: call for A/C (with the furnace only used as a thru-route for that wire).

This is 24V low voltage, can't hurt you. You can't do any damage unless you short R to C (don't do that). You can test by using a wire to short R to W - that should make the furnace start up and the fan will eventually start once the furnace is hot enough. Short R to G to make the fan immediately run (hey, follow the sound to find the furnace!) Short R to Y and the outdoor A/C unit should start up, however it is useless unless you also jump R to G, and DO NOT start it twice without waiting 10 minutes in between (a "short cycle" is a no-no).

That right there is what a thermostat does. (at the appropriate times).

If all 3 tests work, then you should be able to get running using any $30 plain thermostat if you aren't in a position to deal with smart 'stats right now.

The 5-wire cable has its other end at the furnace unit I mentioned. It should be obtaining the C-wire from the furnace unit. The "Y" wire in the cable is probably spliced to another cable to go to the A/C unit. The A/C typically gets a 2-wire cable (red and white, but actually Y and C). In your case it looks like someone used a 5-wire cable for no good reason. It's only using 2 wires in that cable. in fact it looks like they paralleled some). No wonder you're confused. You're at the wrong equipment.

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