For those of you who live in the Phoenix area during the summer, you rarely experience a day in which the temperature drops below 99 degrees. Average high temperature for June is 104, July is 106, August is 104, and September is 100. The last thing you want to hear is a dripping sound of a leak, one indicator that that your air conditioner has frozen.
It is worth explaining how an air conditioner actually works. There is a principle in thermodynamics called the Joule-Thompson Effect. It states that if other factors are kept constant, as a gas expands, its pressure and the temperature decrease; if compressed, the temperature will increase. Your unit works by having the evaporator coil expand refrigerant inside of it, causing rapid cooling of the coil. As the cooled coil comes into contact with the air inside your home, the refrigerant absorbs this hot air. The now heated refrigerant is conveyed outside your home where it is compressed which causes it to heat up and shift the heat that was inside of your home to the outside atmosphere.
Your air conditioner freezes because something has changed this process causing your evaporator coil to cool more than it should. Possible causes for this are as follows:
Other causes could include a poorly maintained air conditioner, dust storms, and proximate trees causing leaves to accumulate inside your unit.
What Should You Do When Your Air Conditioner Freezes
Hopefully by following these steps, you can avoid that awful moment when your air conditioner freezes up during those summer scorchers.