Justin wrote:
Our old thermostat decided to quit so I am trying to replace it with a
"Lux" Brand from Lowe's.

What's happening it the Heat will turn on if we set it to heat and
raise the temp, but the Air conditioning won't activate mo matter
what. Once when I turned the switch to FAN the circuit breaker cut power.

The Central air unit is fairly old... Here is a picture

http://img139.imageshack.us/my.php?image=img0119ib4.jpg


Here is a picture of the thermostat's innards and how we have it
wired:
http://img528.imageshack.us/my.php?image=img0120fz1.jpg

Hopefully I won't get flamed as badly as I did in the other group.
The model is CAG1500
there are five wires: white, yellow, green, blue and red.

When you replaced the subbase, did you wire it back as the same as the first
stat?
If it is the same, you can use a jumper to check the system out by:
RH (Power to Heat) jumpered to W (Heat) then the heat should come on.
RC (Power to Cool) jumpered to G (Blower) then the inside blower should run.
RC (Power to Cool) jumpered to Y (Outside Condensing unit) should come on



--
Moe Jones
http://www.MoeJones.info