This sounds like an abnormal amount of condensation coming out of the exhaust pipe. If properly installed, the exhaust should slope toward your furnace for the condesation to be 'trapped' and drain indoors. You may want to check that for starters. Good luck.

[This message has been edited by CIWS (edited January 08, 2004).]

I just had a high efficiency gas furnace put in and I agree with the other poster that the venting should be laid out to drain back to the furnace. The condensation is then pumped to my utility sink through a condensation pump. I suspect your venting is sloped to the outside where is collects and freezes. Check it out with a leve. In any case--call the company that put the system in to check it out.