Our most common call? Clogged drain line, hands down. But this common little problem, can cause plenty of issues. The condensation pan collects all of the moisture your unit is pulling from the air to dehumidify your home's air. A clogged drain line can cause it to overflow and flood your room as it did for this Fort Pierce homeowner. Combine this with an inefficient or shut down entirely system, as well as the potential for mold growth from all the collected and trapped moisture, and this littl