Our drain pan under the freezer size is so full of water that it gets so full that it pops loose and spills out onto the floor. I had a repairman come out and he replaced our original pan because it had actually split. We thought the problem was solved but now the new pan is overfilling. Isn't the water supposed to evaporate?

Is this something we can fix or do I need a professional. I just hate paying them to come out and then finding out that it was something really simple.

Refrigerators - Sub-Zero - 632 / S