Believe it or not, the most frequent cause of frantic cries for help because “My air conditioner keeps shutting off!” is excess ice buildup.
The first thing that comes to most customers’ minds is low Freon. In reality, however, other causes are far more likely.
Anything that impedes airflow into or out of an air conditioning unit decreases cooling capacity. If left unchecked, a severe imbalance between pressure and temperature can develop to ruin the coil completely.
This occurs because interior dew point remains above the coil surface temperature. When that happens, the coil essentially becomes a refrigerator.
Instead of blowing cool air, it extracts and retains excess moisture that freezes and results in major blockage that can totally obstruct airflow. In a lot of cases, solid ice is clearly visible all over the outside of the coil that looks much like an endless white serpentine chain just behind the grill.
It is very important to realize that the true purpose of air conditioners is not refrigerating air. Rather, the real function of any air conditioner is dehumidifying air by moisture extraction that enhances comfort of the immediate environment.
In order to perform that role, the cooling coil must stay hotter than dew point temperature within the interior area. When the reverse situation occurs, ice will form that eventually blocks airflow into and throughout the unit.
This causes a self-sustained problem of growing ice formation that ultimately “cures” itself by forcing the device to shut down until it thaws out – possibly forever!
Your best bet is to call a HVAC professional and have them take a look.