Water alarm was tripping after air was running for a long period, clearly leaking into secondary drain pan. I assumed drain was plugged, but could not clean. Called technician today, and he indicated I had a bad blower motor on furnace unit (Ruud Achiever 90), and needed to be replaced. He said it was getting hot and then shutting down.
I explained several times that the system wasn't tripping or stopping because fan was overheating but rather was tripping due to water in pan. He 'guaranteed' that this is what the problem was, but I can't figure out logically how it would impact. Does this make sense? At a ridiculous price of $600 to replace, I want to ensure this is right.