I have a Lennox central air system in my house (installed about 20 years ago), and just this season, puddles of water have started to appear underneath the refrigerant evaporator. The strange thing is that it appears that it only happens after the A/C shuts off, not while it is running. We'll run it for hours with no water appearing, but then we shut it off and overnight, a couple liters of water appear around the base of the furnace and evaporator.
I checked the hose that drains the pan that the water collects in, and it is clear. I tried pouring over a gallon of water straight into the bottom of the evaporator, and it all drained just fine.
Any ideas as to what the problem could be? We're wondering if it might be related to another problem we have - one of our outdoor faucets will spray water out of it about 10 seconds after you turn it off, kind of like the pressure is building up after the water stops running. Is it possible that something similar is happening with the water that is supplied to the A/C? What might cause it?
Chris