Air conditioner/furnace was working for the past few months. Came home today at it is at 81 degrees, although my set temperature was set at 72 degrees. Temperature is rising to 83 degrees and I can't figure out why the air conditioner won't run properly. I turned the fan on from auto to on and it's blowing warm air. The default scree on reads the current temperature at 82 degrees with a circle and snow flake above it and an downward arrow where the word room is written. Any suggestions? I tried shutting off the furnace and turning it back on but nothing changed.

Check for a tripped breaker. the fan works on a different breaker. You will almost always find them side by side in the panel.

You have a heat pump.
Once the outdoor temperature falls below 36 degrees, heat pumps will sharply lose their ability to heat.
If you are getting a 72 degree indoor temperature when the outdoor temperature is 28-30 degrees, the heat pump is performing up to spec.
On heat pumps, the air coming out of the nearest air vent to the unit should be heated approximately 40 degrees warmer than the air entering the unit.
If you have a 70 degree indoor air temperature, the heat pump should be supplying 110 degree air at the closest air vent to the indoor unit.
Gas heat is a much better heating source where outside temperatures are commonly below 36 degrees.
Even electric furnaces perform better than heat pumps under these conditions.

The fan relay is stuck in the on position. When the temperature drops the heater does not ignite because the fan is already running and ignition is locked out after the heat cycle starts an the fan turns on

Here is what you need to do to make sure your system is charged correctly go to the furnace take the temperature of to supply temp and take the return temperature at the furnace. You should have 18-20 degrees temperature difference if your return temp. is 77 degrees you should have 57 to 59 degrees. If you dont have these temps your system either wasnt cleaned properly or not charged correctly. If this helps please rate me and do a testimonial.

It might be short cycling. Check this out:

Furnace Lockout notes

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A/C units have a design temperature of 90F. Now when the temperature is above 90F they start to have trouble keeping up. Depending on how well your unit is sized for the house, you will notice when the temp is over 90F. I don't know if who ever looked at your unit checked the refrigerant pressures since you said he checked the temps but I assume he did, however, it could possibly need charging.

carrier infinity 96 furnace went to turn down the thermostat and their was no power to it and the furnace doesnt run

May be the location of the thermostat. Try another thermometer right beside wall thermostat & see what it reads.

make sure the system switch is in the cool position, then press run program button and allow a couple of minutes for system to cycle on, if it doesn't come on press the button for lowering the set point, set it to 72 degrees and then press the hold temperature key.

There is probably a setting between farenheit and celcius. Is it set to Celcius? look in the owners manual to see how to change it to what you need. sorry I can't be of much more help on a window shaker.

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