Rheem air conditioners are dependable units. However, when there is a power outage you might find that the air conditioner does not start right away once the power comes back. The Rheem has several safety mechanisms, one of which is a pressure switch. When the Freon pressure gets too high the switch shuts off the compressor. Sometimes a power outage will cause a surge resulting in shutting off the compressor.
Raise the temperature on your thermostat to 80-degrees Fahrenheit. This prevents the unit from turning on while you are resetting the compressor.
Find the red rubber boot that covers the rest button on the back of the air conditioner case. The reset button is near the copper lines at the bottom of the case.
Press the reset button once with your finger. Set the thermostat to the desired temperature. This usually restarts the Rheem air conditioner. If this does not work, call a Rheem professional to service the unit. Power surges sometimes destroys capacitors in the unit requiring a professional to replace.