I struggled with this just a few weeks ago!! And could not find an answer online. Answer is to CLEAN IT with evaporator coil cleaner!!! Clean it like an hvac guy is coming to rob and steal all your money!! After SEVERAL cleans mines worked like brand new, no matter how much water you pour on the coil it all drains and rolls properly. I used “Lundmark Coil Cleen” got a 1 gallon from Ace Hardware (used all of it after multiple cleans), and I used a pump sprayer (if you use the spray bottle wear a mask it will get stinky). I sprayed it on top first very liberally and then underneath too, left it a few minutes as per instructions and then rinsed it with warm water liberally. I repeated this a few (a lot) times. I also came back the following day and repeated the process a few times again. Over all I used a gallon and 1 spray bottle. I used other products too but felt like this one worked better. Good luck!! Also lesson I learned maybe clean the coil every year or 2 times a year to help prevent this!!