Check out some similar questions!

diiidoug · Aug 30, 2012, 12:14 AM

I replaced an old Hunter t-stat when the unit ran continually no matter what temp... I replaced it with a Honeywell 6350 5-2 programmable t-stat. I have an old Coleman furnace with an ac unit attached using two wires-red/white. I connected the red to R and the white to W. There was already a jumper between R and Rc. The problem now is that the outside condenser and fan assembly are not running. I have the t-stat set to heat and the switch on the unit set to cool. Obviously without the condenser and fan running outside, I don't have cool air. This was working earlier in the day, but just would not stop running. I don't know what to do now, hope someone is on who could help.

hvac1000 · Aug 30, 2012, 12:31 AM

I replaced an old Hunter t-stat when the unit ran continually no matter what temp....I replaced it with a Honeywell 6350 5-2 programmable t-stat. I have an old Coleman furnace with an ac unit attached using two wires-red/white. I connected the red to R and the white to W. There was already a jumper between R and Rc. The problem now is that the outside condensor and fan assembly are not running. I have the t-stat set to heat and the switch on the unit set to cool. Obviously without the condensor and fan running outside, I don't have cool air. This was working earlier in the day, but just would not stop running. I don't know what to do now, hope someone is on who could help.

You probably have a mobile home or possible modular home since you have a old style two wire system. You probably also have a switch on the furnace itself that is HEAT-OFF-COOL. The system you have is not friendly to the new style electronic thermostats unless you want to rewire the entire low voltage setup in your furnace and to do that you wilol have to call on a professional ON SITE service person. Sorry but that is the way it is. PS you can use a old style mechanical thermostat for your system since it will work.

diiidoug · Aug 30, 2012, 12:41 AM

Originally Posted by hvac1000

I replaced an old Hunter t-stat when the unit ran continually no matter what temp....I replaced it with a Honeywell 6350 5-2 programmable t-stat. I have an old Coleman furnace with an ac unit attached using two wires-red/white. I connected the red to R and the white to W. There was already a jumper between R and Rc. The problem now is that the outside condensor and fan assembly are not running. I have the t-stat set to heat and the switch on the unit set to cool. Obviously without the condensor and fan running outside, I don't have cool air. This was working earlier in the day, but just would not stop running. I don't know what to do now, hope someone is on who could help.

You probably have a mobile home or possible modular home since you have a old style two wire system. You probably also have a switch on the furnace itself that is HEAT-OFF-COOL. The system you have is not friendly to the new style electronic thermostats unless you want to rewire the entire low voltage setup in your furnace and to do that you wilol have to call on a professional ON SITE service person. Sorry but that is the way it is. PS you can use a old style mechanical thermostat for your system since it will work.

It is a mobile home and the old thermostat worked well for many years... it finally stopped allowing the unit to turn off. I don't understand why the outside unit now is not working when it was earlier today... it is wired the same way...

diiidoug · Aug 30, 2012, 12:54 AM

Originally Posted by diiidoug

It is a mobile home and the old thermostat worked well for many years....it finally stopped allowing the unit to turn off. I don't understand why the outside unit now is not working when it was earlier today....it is wired the same way....

Sir I just wanted to say how stupid I was... when putting in the new t-stat I tripped the breaker on the panel so as not to get shocked. I then let the unit run it seemed to work. After checking and rec-checking guess what I found? I had not turned the breaker back on that controls the condenser... now I have cold air. The squirrel cage fan seems to run on another breaker. Now playing with the controls on the t-stat, they do operate and turn the unit off and on. Thanks for your quick response!!