At Ask Me Help Desk you can ask questions in any topic and have them
answered for free by our experts. To ask questions or participate in
answering them you must register for a free account. By registering you
will be able to:
Get free answers from experts in any of our 300+
topics.
If the furnace has the same R, W, G, and Y terminal markings, just match the wires to the same terminals at both ends. Usually the red wire comes from the 24 volt transformer and would be jumpered to RC and RH. Usually it is yellow to Y, green to G, and white to W. Likely it will be black to W.
If the furnace isn't marked that way, you are going to have to identify the transformer, heat, cool, and fan using any directions for the furnace you can find.
I also am trying to install the Honeywell RTH230B to replace an older "analog" Honeywell thermostat. I have 4 wires from the heating/AC unit and they are white, blue, red, and green. On the existing thermostat which works correctly, these are attached thusly:
Green -> G
White -> W
Blue -> Y
Red -> R
and there is a jumper between the Y terminal and a terminal labelled 1.
When I connected these wires to the RTH230B, I connected white to W, green to G, blue to Y, and red to RC which is jumpered to RH.
Wired like this, the only thing I can do is switch the fan on. When set in automatic mode and either heat or cooling, there is no way to get the system on. Even with the fan switched on, it only circulates the air, it doesn't turn on either the A/C or the furnace.
I don't understand it. It mostly follows the standard convention except for the jumper on Y to 1, and a blue wire to Y instead of yellow. No problem if the blue wire connects to Y at the furnace too. Maybe better check that. Did the heat not come on at all, or did the blower delay confuse you into thinking it didn't come on? With things connected as you did, and the thermostat set for heat, there should be 24 volts AC between the white wire at the furnace and a B or C terminal at the furnace. If so, the thermostat is working.
I am trying to install this thermostat to replace the old mercury ones. I have 3 wires coming from the old one; green, white and red. On the Honeywell thermostat they have the rh,rc,w,y,g, with a jumper in the rh,rc area. I hooked it up using the red in the in the Rh, white in the white and green in the green. I set the temp for 64 and in about 2 hrs it was climbing until it reached 83 degrees. Why is it still calling for heat? Did I wire it wrong? When I looked at the Furnace there are no markings for what wires are what, but only the green and white wires are connected the red one is coiled around and unused. PLEASE HELP.
If you do a search here, you will find my answers really didn't solve similar problems for others. One reported a still not quite right solution by moving a jumper from HG to HE. Each situation is different. Let's start with the basics.
Usually there is a 24 volt AC transformer in the furnace with the secondary winding connected to a red wire running to the thermostat and a blue wire, common, to the gas valve, A/C relay, and fan relay. From the thermostat there will be white wire to the gas valve, yellow to the A/C, and green to the fan. The thermostat is wired to switch the power from the red to the white, yellow, and green as needed with the blue completing the circuit. Most thermostats and furnaces have the contacts labeled R, B or C, W, Y, and G for the corresponding wire colors. It may be wired to have the A/C control wires return to the furnace and its controls and then a second wire goes to the A/C unit. Internal wiring may replace the green wire if the thermostat does not give you the option of fan only or continuous fan. Digital or programmable thermostats may need the blue wire connected to them.
Did you note what contacts the wires were connected to on the old thermostat? Were either connected to the R? It sounds like the green and white wires were connected one way or the other to the transformer and heat valve on the furnace, and to the R and W terminals at the furnace. If it is an older furnace, you can open it up and trace one wire to the transformer, and the other to a box between the gas line and burner. That is the gas valve. Connect the red wire to the transformer connection and the white one to the gas valve. Connect the red wire to the RC/RH terminal and the white to W at the thermostat. It should now work. If it doesn't, post back, and we will work some more on it. Where did you buy it? If they can't explain how to make it work, maybe they should take it back.
Hey,
thanks for the reply. The house was built in 2005, I looked at the furnace and the green and wht wires are hooked up to an area that says "thermostat" the red wire is coiled around and not used. On the old thermostat the green wire was on the top, the white on the left and the red on the right. I spoke to the person that I thought hooked it up, he said that the old thermostat is numbered 4 on the rt, 5 on the lt and 6 on the top. Now I dunno what that means exactly. I also noticed that if you hook the old thermostat up and you cross the red and white wires that it keeps calling for heat. I can't understand why that would be unless that red wire is used somehow even though it's not hooked up on the furnace. I got the unit from Home Depot. I spoke to their "trained electrician" and he said that it shouldn't matter what order I put the wires in. I hooked it up and it seemed that it didn't work. So I took all of thermostats off and touched the wires together and I came up with 2 sets of wires that worked that turned on the heat. I hooked up those two wires and thought I had it solved, but I am thinking now that I didn't. I am at a loss. I live in alaska and I am not fond of the heat so when the furnace doesn't kick off it's an ugly thing, but I guess equally as ugly when it doesn't kick on. I think it's time to call out the professionals. Thanks for your reply.
I just replaced an old coleman turndial thermostat with a new honeywell RTH230B. My old one was 2 wire.It says to hook the red to rh and white to w.I did this and set it to manual and it seems to want to keep running when i turn the thermostat down. Did i get my wires crossed or is there some program that im not doing right?
You could go to the furnace and make sure the red wire comes off the transformer and the white goes to the gas valve. You can also try changing the batteries. However, several people have reported the same problem, and neither I, nor anyone else seems to have the answer. Honeywell has not seemed interested in helping others. I would go back where you bought it, and ask them to either help you make it work, or give you your money back. If they do help you make it work, you would be doing others here a big favor if you post back telling how.
Linear Mode
