I had a new condensing gas furnace & central A/C installed last fall. The furnace/evaporator are located in my basement. Lately, it's been very hot & humid in my area. The other day I noticed a small puddle of water by the furnace. Near as I can tell the the hot humid air from outside is condensing in the air inlet pipe & running back to the furnace.

Due to this pipe running perpendicular to the floor joists & existing my basement via the rim joist it is not possible to slope it toward the outside. I could plug the pipe at the outdoor exit point, but I really would like to avoid a "solution" which would render the furnace inoperable should I forget to remove the plug prior to the heating season. Currently most of the water is running out of the pipe where it meets the collar on the furnace & not actually going inside. My initial thought is to put a drip leg somewhere on the intake pipe to catch the condensation. Can anyone offer up a better solution?

The install is currently under warranty & I should probably make this the installer's problem, but I thought I'd get some opinions first.

Thanks.

-Dave