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Thumper74
| Posted on Sunday, May 24, 2020 - 09:09 pm: |
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A little backstory should help... my parents built the house in 1996 with no central air. They added central air in 1999 and it was fine till three years ago. We had an programmable thermostat installed and once a year now for three years, we have had a service tech out to fix the thermostat because the ac wouldn't turn on. It would be fixed and then the heat wouldn't come on in winter. The wires are six wires: - red - blue - green - white - orange - yellow I hooked yellow to the y terminal in the thermostat and nothing happened. I checked it at the furnace and there is 24 volts at the wire, but its not hooked up to anything. The orange is not hooked up either, I believe this is reserved for a heat pump. In the thermostat, white, green and red are hooked up, but blue, yellow and orange were not. There are four colors out of the furnace these are hooked to: - white - red - green - blue They are not matched color to color and there are jumpers between them. I have attached pictures showing the wiring at the thermostat and I suspect that one of the other colors, probably red are supplying power to the ac, but don't want to risk shorting something.
Wiring out of the furnace to thermostat wiring.
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Ratbuell
| Posted on Sunday, May 24, 2020 - 09:35 pm: |
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I'd start by reading the yellow tag in the photos, for a color connection guide. Then, get an install manual for the thermostat and see what it says for colors. I have a heat pump, and have wired a heat-only thermostat in the past, but no experience with separate units, sorry. |
Griffmeister
| Posted on Monday, May 25, 2020 - 10:18 am: |
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In many cases you can contact customer service at the company that makes the thermostat. If you give them complete information on your heating and cooling units they can usually supply proper hookup information. Sometimes certain units will have a known issue where you might need something extra like a relay. Doesn’t hurt to go straight to the source. |
Tootal
| Posted on Monday, May 25, 2020 - 01:30 pm: |
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If you don't have the manual for the furnace or thermostat I'd try to go on-line and see if you can locate them from the manufacturer. Read both manuals and compare how they hook up. You might find a difference in wiring diagrams/colors and be able to figure it out from there. Even YouTube might have something. |
Blake
| Posted on Monday, May 25, 2020 - 01:46 pm: |
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Here's mine. Note the jumper between RC and RH, red/heating and red/cooling.
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Thumper74
| Posted on Monday, May 25, 2020 - 07:17 pm: |
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I figured it out! The blue wire was used for the compressor. We are enjoying the cool air right now |
Court
| Posted on Monday, May 25, 2020 - 07:22 pm: |
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COOL |
Tootal
| Posted on Monday, May 25, 2020 - 08:17 pm: |
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Good to hear! I saw that blue wire was stripped and I saw the spot marked with a B. It made sense to put in there but without a wiring diagram I wasn't going to just tell you that! |
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