My thermostat [the older kind] has seemed as if it was showing the wrong temps [showing warmer than it felt]. Now the air blowing out doesn't feel as cold as it was. When I switch to off it blows warm air. I can only shut if off through circuit breaker and that feels warm to the touch. The fan is in the auto mode. I live in a mobil home in Florida. Also, it doesn't seem to have the water dripping out if its pipe outside like it always does. :confused: Any ideas! I can read directions fine but do not know about testing strengths and such. Thanks for any help.

Let the system run for 5-10 minutes. Go out to the outside unit. In addition to the fan running, there should be sort of a put, put, put of the compressor. If it is running, the larger tube coming out to it should be cool and the small one warm or hot. If so, there is little you can do except call a service man. It is is not running at all, a wire may be damaged or the relay bad.

I came across the niftiest gadget for trouble shooting, a voltage detector. They work through the insulation of wires. There are several brands. I have a GB Instruments GVD-505A, less than $15 at Home Depot. Touch it to a hot wire, and the end glows red. Find the doodad that lights it on one side, and not the other, and you have the culprit.

Check the small wires coming from the thermostat with a voltmeter or voltage detector. They should have 24 volts AC. If not, go inside and check at the furnace. The Y and B or C terminals should have the same wires connected to them as outside and again 24 volts AC. If they have power inside, but not outside, the wires are damaged. If they don't have power, either the wires are damaged from the thermostat, or it is bad.

If your getting warmer air the system may be low on refrigerant. May be a leak somewhere in lines. When was the last time the inside & outside coils, filter, blower fan & thermostat were cleaned?

I only have access to outside water heater and outside air conditioning unit with heater package, but not to any furnace. I have found some receipts from previous owner and this 2 1/2 ton unit was installed in '87 and last serviced in '91! So, skiberger, I think its time to call the big boys in. :eek: It could be very simple thing but... Anyway thanks for help and ideas. I'm still open to any thoughts as I won't be able to get a serviceman right away.
Also, Labman, I will be getting a voltage detector, thanks for info.