Mine didn't used to.. checked them tonight and one developed a leak at the bottom of the gate... metal heat duct tape stopped it.Thanks Marco I will keep an eye on them to make sure they close completely. The reason I went with the plastic gates is I have the metal gates already and they leak around the slide really bad. You can actually hear them rattle at times.
Chuck I have a Y 2 feet in front of the DC. open both gates when running the one to the RT?Keep in mind that if you are going to a reduced size outlet like for a router table that the DC will work better if you open a gate upstream from that outlet. The DC needs at least a 4" opening to have enough air flow to work properly and the air from past the reduced line actually helps suck more air from the smaller one.