Water dripping from Heating Duct

[lg_girl]

I have this heating venting in the ceiling where I change my heating unit air filters. It was raining today, and it started leaking from the vent onto the floor. It was a very small amount that I could wipe up with a paper towel, and put a bowl under. It soon stopped--I probably didn't even have more than an oz or so of water. the thing is, it was raining this morning, but we've had much worse rain from Nov-to now with no leak. Last year, the same thing happened and i had the roofer come out to see if there was a leak...he said there was nothing, and it stopped then too. Is it possible it's some kind of condensation?

I have a carrier unit (which I love)....any ideas?

[doc havoc]

Is your Carrier a gas furnace? Is the air handler itself in the attic or just the ductwork? What is the temperature outside when you notice the water? It could be condensation resulting from loose, torn or missing insulation in or around the duct. It could be condensation from the furnace if it is a condensing gas furnace. It could be from a leak in the roof that went unnoticed during the last inspection, or a newly developed leak. Wind strength and direction may play a part as to when the roof leaks and when it doesn't.

[lg_girl]

My furnace is a carrier gas furnace. The furnace is located in a covered area outside, and the ductwork goes from the furnace, on top of the roof (have a flat roof) and down into the house in my hallway which is where I change the filter on the ceiling.

I don't recall the temperature outside. I came home last night in pouring rain, and there was no dripping in the bowl I had left on the floor. In fact the few drops that landed in the bowl had dried up during the day. Based on this info, what do you think? I don't know much about the furnace, but it does have a little box next to it where condensation is moved to the outside for when I use the air conditioner in the summer...does that help?

[beenthere]

Maybe a leak in the duct work.
That the rain has to come from just the right angle for it to get in.