Gently pull the vent pipe away from the wall duct ... the exit point outside the house by removing its duct flap or duct cover. Next you need to buy a specialized dryer vent cleaning kit.

“You can’t just cover the pipes up,” Olms explained. “You can back up your whole system. Deco-Vent allows the 4-inch-diameter pipes to continue to draw the necessary air needed.

J.W. Ypsilanti A. Two words: backdraft dampers. That's what you need on the vent pipes of both appliances. A backdraft damper allows air to flow only one way inside a duct. That means it permits ...

But why would you even want to do that? One of the biggest reasons is to add a vent pipe. I recently had to put in a vent when I installed a radon system that vents gas out of the top of the roof.