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Author Topic: Where does the black wire go?  (Read 3185 times)

Offline Plug

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  • Member Since: Jun 2015
  • Posts: 3
Where does the black wire go?
« on: June 30, 2015, 12:40:50 PM »

Greetings, I'm trying to wire  the A/C on a Trane XV90 gas furnace to the thermostat.

I have three wires that aren't hooked up yet and I'm assuming Y and O go to their corresponding letters, but what about the black one?

Also the O/w1 slot on the thermostat already has a white wire connection. Thanks for the replies.






« Last Edit: June 30, 2015, 12:57:37 PM by Plug »

Offline rabjr01

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  • Member Since: Nov 2014
  • Posts: 16
  • Country: us
Re: Where does the black wire go?
« Reply #1 on: June 30, 2015, 02:49:04 PM »
Model number of the furnace and outdoor unit and I should be able to help

Offline Plug

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  • Member Since: Jun 2015
  • Posts: 3
Re: Where does the black wire go?
« Reply #2 on: June 30, 2015, 03:19:44 PM »
It's a Trane XV90 gas furnace wired to a trane/honeywell thermostat and the outside a/c unit also is Trane. I'm just wondering if I need anything else than  hooking up the yellow wire. I've had three tech's here to look at it and they all said I need a new thermostat that costs over 300 bucks. When I bought the house there were several thermostats laying around. I did successfully wire it up to get heat but not a/c.

I have this type of thermostat but it says Trane on it: https://customer.honeywell.com/resources/techlit/TechLitDocuments/69-0000s/69-2693.pdf 

Much thanks.  ;)





Offline Plug

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  • Member Since: Jun 2015
  • Posts: 3
Re: Where does the black wire go?
« Reply #3 on: June 30, 2015, 08:33:57 PM »
The thermostat is a TCONT802AS32DAA and the air con unit is a tran xl19i. I wired the yellow to yellow and orange to orange and still no go. Is the black wire needed?

Offline rabjr01

  • Technician
  • Member Since: Nov 2014
  • Posts: 16
  • Country: us
Re: Where does the black wire go?
« Reply #4 on: July 01, 2015, 10:24:19 PM »
the XLi is a 2 stage out door unit with 2 compressors from the thermostat you need to be using all the wires you have if it is a heat pump the thermostat is able to be set up for multi stage heat and cooling my I would recommend that you get a trane comfort specialist out they will be able to get everything sorted out and make sure that the thermostat is set up right. I know this is not what you wanted to hear but this is not a simple system to set up