Galley Sink Vent issue
Had smell coming from under galley sink, replaced vent, old one looked pretty gummed up and dirty. Now the sink will not drain unless I loosen the vent, when I loosen it will hiss and sink will drain ...
Forum Discussion
Actually, I disagree with this statement. Holding tank pressure is EXACTLY what the AAV should do. It is supposed to let air INTO the tank, and keep air (and smells) from exiting the tank. What is supposed to let air (and smells) out of the tank is the roof vent, which is exactly why everyone keeps saying to check to see if it is blocked. If you are getting hissing air (and smells) when you loosen the AAV, the tank is pressurized meaning the roof vent is not working.
Another cause for this, rarer than merely a blocked vent, is the vent pipe has come unfastened and slipped down into the tank. That means the bottom of the roof vent pipe is under the water line of the tank, and not venting.
All of your tanks should have a vertical vent that exits the roof.
Buzzer! Nope!
Hey, I'm not a technical writer for a plumbing distributor. Both of you guys would agree with the basic stuff I wrote. Maybe I should have written "drain pressure/vacuum" instead of "drain pressure" and explained that a single pipe can handle two drains. The information remains the same but I'm about done being scolded for not appealing to the sensitivities of some readers.
Instead of scolding, help the guy out.
