OH THANK GOD! DAC, I have a cheap digital camera, but it was out in the truck last night, and must be too cold to work right, anyway, I'll try to describe this mess. The stat is a cheap hunter, with 7 terminals, the square? And B terminal are vacant. The next two are r/h and r/c, the red wire is connected to the r/c, with a jumper to the r/h. The next is Y with a yellow wire and Y that has a brown wire attached to it. G is vacant with a free blue wire. I also have a New Rite TEmp stat tha has never been installed. It might be better. Thank you so much for your help... MAC

MAC please keep your posts together by replying on that post. I've added your original post here. It will help others to follow and add their collective knowledge.


I live in a rental home that has a Lennox g-15 furnace and an outside air unit. I previously had an old mercury thermostat that went bad last summer. I went to Home Depot and purchased a new one and thought I would replace it myself. Well, I didn't color code my wires and ended up not getting it to work right. I called a professional hvac person to fix it and he got the a/c running fine. since it was summer, I didn't think to check if the furnace was coming on. Well, just my luck, it does not work. The old home has baseboard elec. heaters, but on windy days they just don't keep it warm enough. When I turn the thermostat to heat, after about 10 seconds the fan starts to blow, but the gas never kicks in. The furnace was working fine prior to the thermostat problem. The gas is on, the pilot is lit, but no heat. On the thermostat itself, there are five wires coming out of the wall, but only four are connected. It appears to be either blue or green. I sincerely appreciate any help you can offer, because I am disabled, and simply can't afford to call a service man. Thank you so much for your help...MAC

MAC is anything connected to the W terminal?

What model Hunter is it?

Please list all wire colors available as you only listed 4 wires but your original post says 5?

Can you get to the air handler/furnace and see what these wires go to?

Answering all above questions will help a bunch.

Sorry DAC, I'll try to do better... The package of the stat is long gone and I took the unit off the wall but could not find a serial number anywhere... but the instruction sheet says that it is either a 40035A, 40060A, or 40070A, heat/cool thermostat. The five wires are red, white, yellow, brown, and blue. Red is connected to r/c with a jumper to r/h, white to W, yellow to Y, and brown to G. The blue wire is not connected to anything.

Sorry DAC, I'll try to do better... The package of the stat is long gone and I took the unit off the wall but could not find a serial number anywhere....but the instruction sheet says that it is either a 40035A, 40060A, or 40070A, heat/cool thermostat. The five wires are red, white, yellow, brown, and blue. Red is connected to r/c with a jumper to r/h, white to W, yellow to Y, and brown to G. The blue wire is not connected to anything.

Thanks for the clarification.

Can I assume this tstat is being powered by battery?

On almost all tstat, R, W (and sometimes G) are needed to actuate heat. See this page and diagram (http://wiki.xtronics.com/index.php/Thermostat_signals_and_wiring) to understand roughly what's going on inside the tstat. Some air handlers/furnaces only need.

On the surface it sounds like you may be wired up correctly, but there is no way to know unless we follow those wires to their destination, and verify that next. Next step is to follow those wires to the air handler/furnace and see what's hooked up, and if the W terminal (and G if needed) are being energized.

Can you manually turn on your fan?

DAC. No, there is no battery. It is a very simple thermostat. Yes, I can manually turn the fan on. I'll try to send a pic now, and see if that helps... thanks, MAC http://pict0002