A: A drainage malfunction occurs when the high-water level float valve inside the drain pan fails to drop. Please troubleshoot the following potential issues:

Check if foreign objects are blocking the high-water level float valve and preventing it from lowering.
If the unit is equipped with a condensate pump: first verify whether the condensate pump is functioning properly. Next, check for trapped air in the pipeline connecting the drain pan to the condensate pump — in other words, confirm if the pump’s inlet is fully filled with water.