We had a professional business install this new forced air gas furnace into a mobile home (rental) in Nov 2010. The renters told us that there was standing water in the floor vent in bathroom (closest to furnace - within 3 feet) but in none of the others. This is still continuing. I don't think it is condensate or it would be occurring in all floor vents wouldn't it? What could is be? Drain line plugged? If so, do you have instructions/diagram as to how to unplug it?