Air stays in the system. Unless it’s displaced by water.Got it. Seems weird that it would work. I suppose there is still enough room for air to get into the system.
Thought about this, but it's an L-shaped kitchen and all the cabinets are ordered. No chance to move them away from the wall.Though not a direct solution to the problem, if you haven't ordered your counter top yet and have 1.5 inches of room in the kitchen... I moved my lower cabinets away from the wall 1.5 inches, ran the vent in the space and got a soapstone countertop that was 28" deep rather than 25-26". Looks and feels like an upgrade instead of a compromise.