I have an Amana side-mounted furnace and yesterday I found a significant amount of water under and around the blower. Its been a hot summer and I've been running the A/C. I suspect its from there. Help!!!!!
I would remove the water mess and see if it continues to fill up without running the unit. If so the water leak is coming from the line that feeds the unit. That most likely would require you to sweat a fitting or two+.
If it only leaks when the unit is running, it is the overflow/exhaust or whatever it is called. When the unit runs it will need to get rid of the water it creates or does not use. If the later is the case, then it should be PVC and you can just use PVC to fix it.
During my remodel I had a bucket under mine until it got its connection completed... and it filled almost a gallon bucket per hour.
My constant project is my home which was built in 1947. We have remodeled almost all of it and added 1000 square foot in 2007. Lars Construction got me up to drywall and I did the rest.