Hello, I recently purchased a house and there is a little problem with the AC. The AC cools just fine, but the blower won't turn off. You have to unplug the unit from the wall plug inside the AC closet to turn it off. I had an AC tech come by the house the other day and he suggested I change the thermostat...which I did today and there is no difference. On the old thermostat, whether the unit is on off or not, the blower will run. On the off position, only the fan will work, but when you switch it to cool, the compressor outside will turn on, so I guess something is working properly. When I changed the thermostat, there were only 4 wires (red, white, green, and yellow). I'm thinking that at some point in history someone messed with the wiring to bypass something for some reason, but before I begin to poke around in there I wanted to see if any one had any experience with an issue like this before. The unit was installed in 1985 (pretty old) but it runs pretty good. Any help would be greatly appreciated! Thanks to all!

I've been told I have several Freon leaks, not repairable, after calling for service for my central air last spring (2010), and the company tried to sell me a new system, saying the re-charge probably won't last thru the summer (of 2010).....but it did fine, and this summer it has been cooling fine with consecutive 100 degree days and thermostat set at 78. It seems to cycle on a max of 60% during the late afternoon. I am constantly checking the air temp for signs of low freon. My question is, does it harm the compressor to run low? Would it be wise to re-charge at 1st sign of temp rise?