This week my HVAC contractor upgraded my old oil furnace to a new 95% Ruud 2 stage heat/cool variable speed gas furnace. The unit itself is whisper-quiet compared to the old oil unit, but after about 15 minutes of running the exhaust vent starts gurgling and popping from condensation getting blown around from the power vent. Intake and exhaust are both stepped up from 2" to 3" at the unit, the pitch is good, the run is about 20' total in length and there are 5 short radius 90's. My contractor has been back a couple times checking for any blockage in the drain goin from the trap inside the unit to the condensation pump, everything is clear and water is draining fine to the condensation pump. Also, the amount condensation is a lot. I don’t have a lot of experience with the 95+ efficient furnaces, and my contractor says everything is running the way it should. Is this noise normal? Here is a link to a video of the exhaust outside, where the noise is loudest from it echoing through the 3" pvc. https://skydrive.live.com/redir?resid=9ADF4CB14AA96C52!1754&authkey=!ABDQzII A_4wK8a8