My Furnace is a high eff furnace with a power vent. There is a gurgling sound in the power vent pipe, when it is running. I noticed that the vent slopes up then has a 90 elbow then slopes down before it goes outside. I suspect water is being trapped should i fix this so the water flows back to the furnace so it can go into the drain.
There should be a slope so all the water can drain. With enough water in the pipe to gurgle the back pressure may cause the system problems including shutdown and early fan failure.