Winnebago Vista Plumbing

[phil-t]

Anyone know how the vent (indicated in the PIC) functions? Anything I can do to service it (before I attempt to remove it)?
When I dump the graywater tank, I get odor in the MH through the kitchen sink trap.  I think this vent is malfunctioning and the trap is being sucked out.

 

[Gary RV_Wizard]

Those are standard air-admittance valves and yes, they should prevent trap suck-out.  They are available wherever plumbing supplies are sold and simply slip on/off the vertical riser pipe. They aren't intended to be repaired - just replaced.

I suspect the odor you get is through the AAV, not the sink trap. The way it works, it is all but impossible for it to stick closed - it typically fails in the open position. That lets odors leak back inside any time, but it's most noticeable when the tank gets stirred up (like when dumping).

Note that the waste tanks are also vented to the roof, so they can't create a strong vacuum either.

https://www.homedepot.com/p/Oatey-Sure-Vent-1-1-2-in-PVC-Air-Admittance-Valve-20-DFU-Branch-8-DFU-Stack-39230/205395535

 

[ChasA]

Just replace it. They're only a few dollars at Lowes, Home Depot. Its purpose is to allow air into the drain pipe so the vacuum doesn't suck the water out of the trap. Just unscrew to remove.

 

[phil-t]

I'll give a new valve a try.  The only time we get an odor is after dumping the grey tank.  Run some wAZter into the traps and all is well.  I still need to get on the roof and check the tank vent(s). Makes sense that the tank vent would not allow any great suction on the traps.  Maybe it's the nature of the beast! 

 

[Charger1204]

I replaced my aav's and still get an odor if I open a window when driving. I am going to replace the vent covers at the roof with the 360 brand covers and hope that it keeps the odors from seeping back into the interior.

 

[John Canfield]

We found that if we didn't run the washing machine occasionally we would get interior odors. Also try to make sure the roof vent to the gray/black tank isn't loose at the tank.

 

[phil-t]

I dumped both tanks yesterday before leaving the park we were in, black first.  When I pulled the gate valves, I did so slowly - gradually to full open.  No problems with odor, this time.

 

[catblaster]

I replaced my aav's and still get an odor if I open a window when driving. I am going to replace the vent covers at the roof with the 360 brand covers and hope that it keeps the odors from seeping back into the interior.

I had the same problem, the more I open the roof vent the worse it got. Final cure was to buy a smoke generator and found so many leaks and one was big enough for a cat to crawl thru. It was from the compartment where the sewage hose and connection was located. Four cans of foam later and the problem is almost gone.  Apparently Winnebago doesn't consider sealing the floor to compartments a priority.

 

[Rene T]

I dumped both tanks yesterday before leaving the park we were in, black first.  When I pulled the gate valves, I did so slowly - gradually to full open.  No problems with odor, this time.

I don't see wwere this would fix your problem or even how they're related. I'd be leery pulling the black tank valve slowly. You want to open it right up so you get a good flush. Opening it slowly could allow much of the liquid to run out possibly leaving solids behind. The AVV valve may be stuck shut. Remove it and dump water in it from the top  side if you can and see if water leaks out.  If it doesn't, it may mean it's stuck shut. It may be just as easy to replace it.

 

[phil-t]

I don't see wwere this would fix your problem or even how they're related. I'd be leery pulling the black tank valve slowly. You want to open it right up so you get a good flush. Opening it slowly could allow much of the liquid to run out possibly leaving solids behind. The AVV valve may be stuck shut. Remove it and dump water in it from the top  side if you can and see if water leaks out.  If it doesn't, it may mean it's stuck shut. It may be just as easy to replace it.

I agree with this - Not a "fix"; but a way to avoid the problem, is what I was looking for (prevent the initial "big" suction on the drain traps).  All I did was open the valve(s), fully, over a period of a few seconds instead of in 2 seconds.  I am in a location now to check the AVV valve and will do so.