Thank you for writing to me. I hate letters like yours. Water can get in the coil if all the freon has leaked out and there is a hole in the heat exchanger. Usually it is a PH issue that wipes them out. Not all the time though. There was one brand that had bad heat exchanges to begin with and they failed after a few years due to a pipe rubbing (vibrating) in the water. The new heat pumps that are made out of titanium will insure that, that problem will never happen to you. Some even say that if the heat exchanger fails in 10 or 15 years and damages the heater that they will send you a new heat pump. It is almost impossible to repair a water logged heater in the field. I have tried. Get a new heater with a long warranty and you will be better in the long run. Don't waste money on this if there is water in the system. I have some favorites if you decide to go that route.
Please let me know if you have any other questions or would like me to call you.