Thanks for your comments. Yesterday I tried to climb the roof that is at 45 degrees to seal the flashing. But I finally gave it up because it is too difficult to climb it. The shingles have sand. It is very slippery. I will call a roofer to handle it though it is probably not difficulty to fix the problem, sealing it because by further carefully check the top of the furnace pipe in the attic; I did see light through on one side. The water must drop from there. I can fix the problem but I am unable to climb the roof at 45 degrees. Though I will call the roofer, I would like to hear what good ideas you have to climb the roof. If one uses a Harness, he still needs to climb to the top of the roof and nail on it before he can use it, right?

It could be refrigerant leaking, but I doubt it personally. R410a refrigerant has a sweeter odor to it. It could also be dirty sock syndrome. Search that on Google and you can learn about it. A service tech would be able to properly diagnose this issue and propose a solution. Take care.

I had water on the floor under our Bryant Plus 90, and for the longest time couldn't figure out what was the source. I read lots of posts here and elsewhere, talking about hoses and other items which could get leaky, but everything here looked OK, after removing the panels on the front of the furnace to inspect the thing. I did finally see some water drops way in the back, near the bottom, needed a strong flashlight to spot these, but they were a false lead, the problem came from what is apparently a real common source - a clogged condensor drain, which is the large white plastic box with several hoses attached to it. The thing is, it looks OK just sitting there, but it will get clogged up internally, and you won't even suspect it. That water you see on your floor was supposed to pass through the condenser drain and on to the little sump pump. When I pulled off the largest of the hoses connected to it on the top of it, I could see that the hose was overflowing with water, and had a paper cup at the ready. I filled that cup over and over, just by tilting that hose downward, and removed over a quart and a half of water, hiding invisibly in the chamber behind the air blower, hoses, wires etc. Think about it: the furnace has that small water pump in the back of it, for what? To remove the large amount of water which condenses inside the furnace most of the time, and if you have water on your floor, most likely the drain-off setup of the furnace has been disabled, this typically won't be caused by rotting hoses, bad seals or any such thing, no, the water is not really pure and will, therefore, wind up clogging the setup somewhere. On page 14 of my Owner's Manual it says that the (white plastic) condensate drain should be cleaned out ANNUALLY. So now you know why. The manufacturer should put that little tidbit in large print in a special box on page 1 on the manual, then you'd spot it. So, to pull those hoses off of the white box, squeeze with pliers the hose clamps carefully so as not to tear the rubber, altogether there are 4 hoses. But then, the box doesn't want to be removed, because there are 2 large bendable tabs on it - pretty easy to not notice them, but with a quite large slip pliers you can squeeze these tabs together, which will then enable the white plastic box to be pulled out from below. After I did this, I poured water into the top of the box, sure enough, no water came out the bottom of the box, which meant that it was clogged. I used then my laundry tub hose to force water into the top, and out blew the clogged gunk from the bottom. Quite a sight. After reinstalling the box, both my wife and I noticed a distinctly higher temperature on the furnace vents upstairs, seems likely that the overflowed water buildup was raising our gas bill too. - granddad314

What is the temperature in the attic? If it is not heated then I am fairly confident condensation is occurring. A single wall vent pipe is the perfect environment for condensation. I also think having a single wall vent pipe going through a ceiling and roof deck is a code violation. The pipe can't touch anything combustible material. It needs to be a double walled pipe. This would also solve your condensation problem.