Ducting Systems and Air Ventilation - Electric Dryer Vent Help

Last fall when we thought the dryer was broken I finally got the idea to check the venting in the attic and not just at the back of the dryer. It was almost totally full of lint! Scary huh? I felt lucky. I got it all cleaned out and things were fine. The clothes started to be a little less dry again this past week. I cleaned out the vent pipe again, not nearly as bad as before, but seemed too much for about 1 year, or is that normal?

It vents up a wall then through the attic and out the roof. One issue is there are 2 elbows coming out of top of the wall into the attic to dodge a 1.5" PVC pipe, then continues at a 45 degree angle to the roof. All in all a total run of about 20'.

I think part of the problem lies with the 2 elbows needed to jog around that PVC pipe. What is that PVC pipe for? It seems like it comes out where the master shower is and then runs across the attic floor and disappears toward the other shower (I haven't investigated the other end yet). It's definitely not the bath fan exhaust. Is it some kind of vent? Can I jog the PVC around instead and eliminate an elbow?

I understand the 45 angle of the vent pipe has to do with limiting condensation running back down in the cold attic right? Whether I adjust the PVC or not, could I run the dryer vent straight up through the roof eliminating some of the length of the run and the two elbows?

There is lint buildup above the two elbows, so it is not the only issue, could there be something wrong with the roof vent?

Thanks.

The roof vent probably has a damper. Check it with the dryer running to see that it is opening properly. The PVC is likely vent pipe. Track it and see if it ends up going out of the roof. Not too hard to cut and reconfigure as it only carries (stinky) air. Check the assembly of the dryer ducting and elbows. If they are held together with screws, they can snag the lint, adding to the buildup. Replace with duct tape. Finally, I hope you are removing and cleaning the built in lint filter on the dryer after each load.

With as many elbows and length of duct run that you have, I think the best thing you can do is install an inline Dryer Boosting Fan with a pressure switch. the pvc should have nothing to do with the dryer venting. Fantech makes a very good one model DBF110 comes with a pressure switch on it. It installs inline with your duct, and should be installed after all the elbows and turns closer to where your duct actually leaves the house. Check out Fantech: Fans for your home ventilation solutions (http://www.fantech.net).