Air Conditioning - Water Leaking from Furnace after New Installation

Hi,
I had a new Goodman Gas Furnace and Coil installed horizonally in my attic, it's a split system. After the install, the A/C guy let the unit run on heat and cool for about 30 min. Everything worked fine except water started dripping from the furnace. My installer said it was because when he tested the unit he left the furnace cover off which caused water to blowback in the unit, and that it would stop leaking after he put the cover on and the unit dried out. Now weeks later, I've started running my air and it's dripping water. Can anyone tell me what's wrong? Could something have been installed wrong or maybe I got a defective unit?
Thanks!!!

Could be a number of things, its more then likely an easy fix. Call the installing contractor back out, I am sure they won't give you a problem as this should be a warranty issue.

might be a mis-pipe on the condensate pan drain off or worse.he installed a vertical unit as a horizontal,and the pan is on the vertical:eek:check the location of the coil and see where the condensate pan is pour some water into it see how it flows.