You set your thermostat for 72 and the temperature just keeps rising in your house.  You check your thermostat again and then you go outside to find this…

So now what do you do?  Here are a couple of things that you can look at that might be causing your problem.  First turn your thermostat to off and the fan to on.  This will help defrost the unit.  Then you can check your furnace filter.  If it is dirty change it.   A plugged furnace filter can cause your A/C unit to freeze up.  Also check your outdoor unit to see if it is plugged up with cottonwood, grass, or other debris.  If it is plugged clean it by just spraying it down with a hose to get the debris off.  Wait until the lines are no longer froze up and try it again.

Restricted air flow is a very common cause of frozen air conditioners.  

If that doesn’t work then you will need to call a service tech. 

Here are a couple of other things to keep your A/C working properly:

  1. Do not let dogs, cats or animals urinate on the outdoor unit.  This will corrode the unit and cause a refrigerant leak.
  2. Keep grass, weeds, leaves and other debris away from the outdoor unit.
  3. Do not build a deck or anything else close to the top of the outdoor unit.  This will cause the warm discharged air to circulate back into the unit.
  4. Never turn the A/C off  than back on in less than five minutes, this will short-cycle the compressor and  can trip breakers, blow fuses, or cause permanent damage the compressor. You  should have a time-delay install on the A/C to prevent this during power  outages! Most digital programmable thermostats have a time-delay of 3-5 minutes built-in. Having a start  capacitor and relay is a good idea. This will increase the life expectancy of  the compressor by starting faster thus keeping motor temperature down, using  less electric to start.
  5. Never leave the house  and turn OFF the A/C. then come back home and turn it on and expect it to cool  the house anytime soon. Doing this will not allow the unit to cool down the  house for several hours. You can set the temperature up five to ten degrees but NOT  OFF. This is because of Latent heat buildup in the walls and furniture in the  house and will make the A/C work harder to remove the heat, this takes a long  time.
  6. On your thermostat set the fan to ON.  This will run the indoor fan  nonstop. The outside A/C unit will still cycle with a call for cooling from the  thermostat. The constant air moving will keep you cooler. You can probably keep  the thermostat a degree or two higher than normal and still feel comfortable.  You will also maintain a more even temperature between upstairs and downstairs.  This will SAVE you MONEY because the outdoor condenser will not come on as much!