grey tank vent on 2018 3050S sunseeker

[mgg]

When I dump the grey tank - near the end, there is a chugging of air back up into the tank. There is only a black tank vent through the roof. There is of course the "air adminttance" valve near the kitchen sink that is supposed to let air into the tank but not out - which I presume is either broken or can't possibly let enough air in to make up for the water rushing out.

And if it all worked - how does air get out of the tank when you run water down a drain? Back up through the P-Traps?

Why no grey vent. Is this yet another way FR saves a few bucks by designing a deficient system? Anyone know how the grey system is built on this unit?
tnx
mgg

[Steve-W]

The gray vent is tied to the single vent pipe that you can see. The tie point is in the wall behind the shower and the bedroom wall.
There is also an air admittance valve under the vanity sink.

As far as the chugging, I experience the same thing. My guess is thats it’s from the tank flexing.
Also it is a good idea to run a bit of water into the sink traps after dumping. When you dump the water in traps may be sucked out, that can result in a bad odor if you do not add water to the traps. The gray tank odor can smell as bad as the black at times.

[mgg]

I figured they short-cutted a connection into the black vent.

BUT - why does the black tank seem to vent fine when dumping, but the grey tank doesn't? Does the grey vent connect in the wrong place - I.E. not into the top of the grey tank?

The problem isn't just the chugging. If the tank isn't venting- and I'm pulling 20 gallons of water out before it gets a chance to vent, then the entire tank and anything connected to it is flexing inward. I don't want to guess how many times I can do that before something starts to leak.

I need to pull some covers and look inside.

mgg

[Steve-W]

I'd like to know the answer to that as well. Let me know what you find. I looked at things as best as I could by removing access port and using a flexible scope.

[Nancyc7]

Originally Posted by Steve-W

I'd like to know the answer to that as well. Let me know what you find. I looked at things as best as I could by removing access port and using a flexible scope.

What flexible scope did you use? I really want one, I think for a RV you need it.

[Steve-W]

Purchased one from Harbor Freight. Not the greatest but for infrequent use it serves the purpose. With the usual 20% off cupon I think it was around $60.