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Freep
Explorer
Aug 23, 2020

Cheater Vent - Air Admittance Valve

The air admittance valve(AAV) also known as a cheater valve was not closing properly in my TC and was stinking up the place. I sealed it off since I already have a vent on the roof. Now I'm wondering, do I really need an AAV? I don't have one under the sinks in my house and they work just fine and water flowed into the gray tank without issue when I sealed it up during our trip.

Opinions and experiences welcome.

13 Replies

  • The AAV is not there to vent your holding tank. It's there to ensure a smooth flow of water and not drain the traps.
    vermilye is correct, they are there for a reason. If you can get away with no AAV and cause no problems, good.
    Personally, I would replace the valve. You may be okay today but, could have problems when you're boondocking out in the sticks.
  • It depends on the run from your sink to the gray tank. If there is not enough ventilation, a large stream of drain water will siphon out the sink drain trap, letting gray tank gas out the drain. If you can let a large volume of water drain out of the sink without starting a gray tank stink in the sink, you may not need it. In most cases, it is there for a reason...