My air handler is an a crawl space (ugh). We recently had flooding in SC and our lake got close to the house, but not into the crawlspace as far as I know. I looked under the house from both sides after the rain stopped and the only water I saw was minor, around the entrances. I did not crawl in to examine every square foot, but it looked pretty dry. Now I have my regular 6 month HVAC checkup, with a new, but seemingly reputable vendor. He tells me that the crawl space flooded over where the air handler is, and that the water got high enough to soak the insulation, but not high enough to otherwise do damage to the unit. He showed me, and indeed the insulation was soaked, and there was a little water over and under the messed up vapor barrier. The contractor says the only solution is a new air handler. Mold and all that. This one is only 4 years old and I hate to replace it just because of wet insulation. So yesterday I tore out the wet insulation to the best of my ability and hope to replace it with rigid foam. I don't know if that will work or not. But I'm skeptical that my crawlspace flooded just by the air handler. Could it be a blocked/defective condensate pump? If that's it, and my rigid foam solution works, how do I test the pump to keep it from happening again? Any thoughts on the whole situation are welcome. Thank you.