Why Air Conditioner Coils Freeze Up is due to many reasons.
It needs consistent airflow to maintain the cold coil warm. To keep the coil staying cold, and its temperature above freezing, the warm air from home is required.
Without the warm air coming from the home, it can result in a frozen coils even before you draw the condensed water from the unit. Causing the airflow to stop because of dirty air filters and closed air registers. You should check your air conditioner’s air filter and clear out and open the registers.
Low refrigerant and improper fan operation can also cause the air conditioner to freeze up. Coils that are too cold along with a faulty fan can prevent the air from moving.
Other reasons why your AC freezes up is because of faulty thermostat and drainage problems. When the AC unit is in its cooling process, it condenses the water vapor to liquid form that eventually drains outside.
Your air conditioner unit will not properly cool your home because of the frozen coils that causes blockage for the drain hole. It uses more elecricity that its normal running state.
Drainpipes are also prone for any blockages from debris and twigs.
Always remember that if you turn an air conditioner on with frozen coils can cause great damage to the compressor. The compressor is the most important and extensive part of the unit. Repair or replacement of that part can be very expensive.