Who thinks the grey tank needs a second vent?

[John E Davies]

The isolation valve under the front dinette does a great job of preventing grey water from sloshing up through the shower drain when towing ......

 

BUT it also blocks off the vent system. So the only way for the grey tank to vent is through the kitchen sink. I have had “burping” occur on fast high mountain climbs, where the tank sends stinky smells up through the water trap as the air inside expands quickly.

 

Plus the main sink is really slow to drain unless you pull the handle.

 

And dumping the tank is much slower without it open.

 

Leaving the kitchen sink plugged may help with burping, but then the draining issue is much worse.

 

A second 1 inch or larger vent line that bypasses the valve, loops high (to prevent fluid passage) and tees into the vent lines under the front vanity would help things work correctly. I know that a long low tank design has inherent problems, but the system could work much better.

 

Comments?

 

John Davies

 

Spokane  WA,

 

 

[STEVEnBETTY]

John, you have waaaay to much time on your hands. Driving a truck for as long as I did, my wife diagnosed my problem with to much time to think, pretty early on. Both of our sinks drain just fine, and my solution for sewer gas bypassing the traps is to put the sink stoppers in when we are traveling.

 

Steve

[BackofBeyond]

I just leave the valve open, only close it when towing. No issues with smell, but then I have the composting toilet.

 

 

[bhncb]

Unless the earlier models are different than the 2018s, there are already two vents.  The black tank vent also serves the bathroom sink and shower drains, and functions independent of the gray drain slide valve. The gray tank vent is off the sink drain just as it turns down to the tank. It is located  inside the galley cabinet in the extreme upper right rear corner as you're facing the galley. The fact that it vents inside the trailer is probably another topic for discussion, but most likely it is the source of gray tank odors rather than from the drain opening itself. I'd recommend checking this vent to be sure it is not blocked.

[Mainiac]

Never had a problem. Do you ride in the trailer, over rough roads, listening for "burps"?  Agree, you must have too much free time. Leaves are turning, deer are moving, moose are in rut...there are more things out there to keep us entertained...

[Townesw]

I think that vent located inside the kitchen cabinet is an air admittance valve. It only lets air into the kitchen drain pipe so that the vacuum created by water flowing through the pipe doesn’t suck the water out of the kitchen p-trap. The water in the p-trap is what keeps the odor from the grey tank out of the cabin.

[Rumline]

I just leave the valve open, only close it when towing. No issues with smell, but then I have the composting toilet.

No problems with odor here either, even though I have the "stinky" traditional toilet.

 

I've learned to leave my shower drain valve open most of the time as well, especially when dumping.