My old thermo has 4 wires(Red,White,Yellow &amp; Blue).Wish one is the "C" wire for power ?
918901
You need 5 wires for this, but have options. First, I'd pull the thermostat and check the cable closely. There may be a 5th wire in the cable (not used on your old thermostat) that's been cut off or pushed back into the wall. If not, you can use the "Venstar Add-A-Wire 5 Wire to 4 Wire Adapter" to avoid having to replace the cable. You can download the manual to check color code and compatibility with your unit.
982917
Mary, I am not an electrician. I also did not have corresponding yellow wires, but did have two wires that went into the unit I replaced. I just connected to the two wires going into old thermostat and I was good to go.
1368889
it is a 3 wire and for heater/furnace only. you need to jump up to a 5 wire if you have air conditioning as well..... Google told me to tell you that.
1264983
I suggest you download the manual and wire it per the instructions in the manual. Important! The Wi-Fi thermostat requires a C wire to operate. The C, or common, wirebrings 24 VAC power to the thermostat. Many older mechanical or battery operatedthermostats do not require a C wire. If you don't have a C wire, try:* Looking for an unused wire that is pushed into the wall. Connect that wire to C andcheck that it is connected to the 24 VAC common at your heating/cooling system.Note: Not all heating/cooling systems label the 24 VAC common C. Check your systemmanual or contact the manufacturer to find out which terminal is the 24 VAC common.Or, call a qualify service company and have them solve the problem. I suggest you download the manual and wire it per the instructions in the manual. Important! The Wi-Fi thermostat requires a C wire to operate. The C, or common, wirebrings 24 VAC power to the thermostat. Many older mechanical or battery operatedthermostats do not require a C wire. If you don't have a C wire, try:* Looking for an unused wire that is pushed into the wall. Connect that wire to C andcheck that it is connected to the 24 VAC common at your heating/cooling system.Note: Not all heating/cooling systems label the 24 VAC common C. Check your... » Read More I suggest you download the manual and wire it per the instructions in the manual. Important! The Wi-Fi thermostat requires a C wire to operate. The C, or common, wirebrings 24 VAC power to the thermostat. Many older mechanical or battery operatedthermostats do not require a C wire. If you don't have a C wire, try:* Looking for an unused wire that is pushed into the wall. Connect that wire to C andcheck that it is connected to the 24 VAC common at your heating/cooling system.Note: Not all heating/cooling systems label the 24 VAC common C. Check your systemmanual or contact the manufacturer to find out which terminal is the 24 VAC common.Or, call a qualify service company and have them solve the problem. « Show Less
1889336
It worked for me. There are instructions about where to put the 2 wires. It's just a relay closure. But, when I asked Honeywell about it I got an answer from someone who apparently was clueless about electronics. But, I used it on a system with ~ 15 volts to the relay and it was fine. That was about 6 or 7 years ago. Now there are "millivolt" thermostats. Some systems have a very low voltage sent to the relay. I don't know if the (thermo)stat you're asking about will be used in in such a system. If so, better check. My system was very old. But, basically, yes, only two wires are needed.
1540894
Not sure about your heating system, but mine has two wires only. I connected them to R and W with no issues.
1066006
The Wi-Fi thermostat must be powered by 24vac at all times, so it needs a power supply (typically red) and return wire (C or common). Most thermostats don't require a return wire. Take your thermostat off the wall and look and see how many wires you have. If you have both a furnace and air conditioner on one thermostat, you will probably have four wires attached: red (24v power), white (furnace relay or gas valve), green (blower relay), and yellow (compressor relay), though colors may vary. If you're lucky there will be a spare wire you can use for the C (common) wire. If not, you can run an additional wire from your furnace/boiler to the thermostat. Check out this web site: http://www.epatest.com/store/resources/images/misc/how-a-thermostat-operates.pdf It has schematics for just about every possible thermostat arrangement.
260039
Assuming that you have heat only, the white (ground) wire connects to "W" and the red wire to "R". A call to the company who installed the furnace generally works.
65908
It's a 4 wire. All in all, we're not satisfied with it since it started to corrode very quickly
1781925
If you are using a J or K type thermocouple, they would go on 9 and 10. With the red wire going on the one labeled (-). Red is (-) on thermocouples and White or Yellow is (+). If you are using a platinum thermocouple it would go on 8 and 10.
1191907
I didn't have a C wire when I installed my thermostat. From what I can figure, the C wire is used for power, and the batteries will kick in when the power goes out. My previous thermostat was programmable with batteries. The batteries lasted a long time in that thermostat. You can set the temperature range where you want and leave it. For some reason, my Vera 3 set up 3 thermostats. 2 are like ghost thermostats, and 1 is the real one. But, I can access and control that thermostat from anywhere. I also set the poling time lower so that it checks the temperature on the thermostat more often. I think I set it at 1/2 hour.
1318957
It has a battery for memory back up, but it runs off the C wire. Be sure your thermostat setup has a C wire.
982918
My thermostat has two wires and my solenoid value has two wires. I just connected one wire from the thermostat to one wire to the solenoid. Likewise, I connected the other wire from the thermostat to the other wire to the solenoid. The two transformer wires that provide power are connected directly to two terminals within the thermostat - under its cover.
1201133
Mine is hooked up as Heat only So I only have two wires as well. If yours is the same you would hook up to C and Rc. After you do that go to where your relay for the circulator is and make sure it is not chattering (rapidly opening and closing). Good luck
136935
I really dont remember. I either used the plug in cord that came with it or purchased a longer one and installed that -- 3 wires. Mine is installed with a 2 foot electric 3 prong plug. I purchased the on/off switch which lets me adjust the temperature. Again, not a hard thing to do.
570887
Here ya go. Hook up the red & green wires for heat. I'm assuming you don't have A/C hooked to your thermostat.http://www.ehow.com/how_5552276_wire-honeywell-thermostat.html
1665390
I don't believe so because this thermo is designed for single-stage. Here's a pdf of the wiring diagram for your review. http://www.emersonclimate.com/Documents/White-Rodgers/instruction_sheets/0037-6754.pdf