(1) Damaged Drain Pan – Make sure the drain pan isn’t cracked.
(2) Clogged Air Filters – Dirty filters can stop air flow and cause evaporator coils to freeze up and stop functioning.
(3) Condensation from poor insulation – Moisture around air vents of poorly insulated ducts.
(4) Low refrigerant – With low refrigerant, the evaporator coils will more than likely freeze.
(5) Clogged drain line – If the drain line is clogged, it can cause the overflow pan to overflow.
(6) Broken condensate pump – If your condensate pump is malfunctioning, the moisture from your AC unit cannot be pumped out and leakage will occur.