Hi, I bought a new thermostat(programmable Honeywell RTH230B). My old one is also a Honeywell, really old round one. I couldn't see the color of the wires through the plate. I had to take the plate off which meant disconnecting the wires. So when I took the plate off, I could not tell where the wires had connected. I have 4 wires, blue, green, red and white(I assume it's white, its so old and discolored it's hard to say.) The new therm needs a white, yellow, green, rh and rc. I called Honeywell and they said that they couldn't help me if I couldn't tell them where the wires were connected on the old therm. I really would like to get this connected. Its 88 degrees and I'm in a second floor condo. It's hot.
I really don't want to call someone to do it. I was so proud of myself when I bought it. I refuse to give up and be a dumb female.

Hi! At the beginning of this forum you will find "stickys".. They are questions and answers posted so you may find some help there... Try there first. There is information as to where the wiring on a thermostat SHOULD go.
Good luck

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Originally Posted by kathyt

Hi, I bought a new thermostat(programmable Honeywell RTH230B). My old one is also a Honeywell, really old round one. I couldn't see the color of the wires through the plate. I had to take the plate off which meant disconnecting the wires. So when I took the plate off, I could not tell where the wires had connected. I have 4 wires, blue, green, red and white(I assume it's white, its so old and discolored it's hard to say.) The new therm needs a white, yellow, green, rh and rc. I called Honeywell and they said that they couldn't help me if I couldn't tell them where the wires were connected on the old therm. I really would like to get this connected. Its 88 degrees and I'm in a second floor condo. It's hot.
I really don't want to call someone to do it. I was so proud of myself when I bought it. I refuse to give up and be a dumb female.

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Here is the link for your thermostats wiring diagram.
You will probably need to jumper r and rh if you have a single transformer.

Blue wire is probably the signal circuit for the outside A/C unit so it will be Y on your new stat.

http://customer.honeywell.com/techli...0s/69-1800.pdf

The rule of thumb, if the first stat was wired correctly is red wire to R,, white wire to W or RH,, green wire to G,, and the blue wire or should be yellow goes to Y on your stat,does you new honewell have a built in factory jumper from RH to RC,many do,, read the paper work it should say if the stat needs a jumper from RH to RC., you may need to look on the other end of stat wires in your furnace and see what each color is hooked to, probably the blue is going to A/C

If you checked the sticky as Missouri bound suggested, you may have had it going before the others posted. Northern Heat did a fine job on it, great resource. Another vote for the blue to go on the yellow. When in doubt, go to the furnace and see where things are connected. You need a pair of wires from the Y terminal of the thermostat and the common at the furnace out to the coil of the compressor contractor.

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Originally Posted by wmproop

the rule of thumb,,if the first stat was wired correctly is red wire to R ,,,white wire to W or RH ,,,green wire to G,,,,and the blue wire or should be yellow goes to Y on your stat,does you new honewell have a built in factory jumper from RH to RC,many do,,,read the paper work it should say if the stat needs a jumper from RH to RC.,,,you may need to look on the other end of stat wires in your furnace and see what each color is hooked to,,probably the blue is going to A/C

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There is a built in factory jumper from RH to RC. So what do I do with the red wire?

Land the red wire one one or the other RH or RC. It does not make a difference since they are jumpered.

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Originally Posted by hvac1000

Land the red wire one one or the other RH or RC. It does not make a difference since they are jumpered.

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Thanks, I'm going to try. Wish me luck!

Good luck I hope it works out for you.

''# R (red) or Rh (Red heat) 24 volts from equipment.
# Rc (Red cooling) 24 volts from transformer in cooling equipment.''

The information you needed was right in the sticky that 2 of us pointed you to.

It also showed blue as an alternative to yellow.

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Originally Posted by wmproop

the rule of thumb,,if the first stat was wired correctly is red wire to R ,,,white wire to W or RH ,,,green wire to G,,,,and the blue wire or should be yellow goes to Y on your stat,does you new honewell have a built in factory jumper from RH to RC,many do,,,read the paper work it should say if the stat needs a jumper from RH to RC.,,,you may need to look on the other end of stat wires in your furnace and see what each color is hooked to,,probably the blue is going to A/C

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The RC and RH is for if you have a two transformer system. If you hook the white to the RH with the jumper in place your heat will never shut off.

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Originally Posted by labman

''# R (red) or Rh (Red heat) 24 volts from equipment.
# Rc (Red cooling) 24 volts from transformer in cooling equipment.''

The information you needed was right in the sticky that 2 of us pointed you to.

It also showed blue as an alternative to yellow.

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Again, I don't know what any of that means!!

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Originally Posted by kathyt

Hi, I bought a new thermostat(programmable Honeywell RTH230B). My old one is also a Honeywell, really old round one. I couldn't see the color of the wires through the plate. I had to take the plate off which meant disconnecting the wires. So when I took the plate off, I could not tell where the wires had connected. I have 4 wires, blue, green, red and white(I assume it's white, its so old and discolored it's hard to say.) The new therm needs a white, yellow, green, rh and rc. I called Honeywell and they said that they couldn't help me if I couldn't tell them where the wires were connected on the old therm. I really would like to get this connected. Its 88 degrees and I'm in a second floor condo. It's hot.
I really don't want to call someone to do it. I was so proud of myself when I bought it. I refuse to give up and be a dumb female.

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I agree we can make things complicated here at times. Try it this way (its just a stab in the dark because I can not see how your unit is wired) Blue to Y, Green to G, White to W, Red to RC or RH. If you have a jumper wire from RH to RC keep it in place.