Vent issue-help me understand this
Evening everyone, I seem to have an issue with the gray tank venting properly, and it only occurs while taking a shower. There is a rotten stench that comes from a ceiling level kitchen cabine...
Forum Discussion
coolmom42 wrote:
Your air admittance valves in the drain lines have failed. There is one under both the kitchen and bathroom sinks somewhere. They are supposed to allow air to move in one direction-- into the drain lines when you dump the tanks, to avoid sucking the P-traps dry. But they are letting stinky gas from the gray tank in, when the gray tank space is being filled by your shower water.
When you open the tank drain, that lets the displaced air go on down the drain. Right now it's burping back up through the air admittance valves.
Air admittance valve
It's also likely your tank vent is plugged--either with bird or insect nest. The tank vent could also have slipped down (at the factory) and be sitting right on the bottom of the tank.
While this information is correct, I recommend staying away from the cheap, $5 black ABS valves like posted in the link as they are known to leak. I recommend the Studor 20346 REDI-VENT Air Admittance Valve, $13.71 on Amazon with free shipping, $19.95 at my local Home Depot. These are residential quality and the valve inside is superior to the cheap ones. I recently replaced both of mine with the Studor valve.
Studor Valve
