Sewer smell when going down the road

[soccerloco]

We have a 2011 stealth lx3112 toy hauler that we use three weekends a month. I maintain black water tank by using chemicals flushing every other dump cycle. However when we are traveling and then go into unit it smells of sewer. Normally I turn on bathroom fan and within a few minutes smell is gone. While stationary no smell at all. Shy idea?

Thanks
Bill

[KyDan]

Negative air pressure in the trailer is pulling sewer gas up thru the toilet.
If you have a thetford toilet this is normal. They are NOT air tight by any means.
I actually talked them into sending me a new replacement free because I thought mine
was defective. The replacement is just the same as the original.
Any time we have negative pressure in the trailer we smell the toilet.
Example, cold weather, trailer shut tight, run the stove vent while
cooking breakfast. The smell is there in the bathroom due to air being pulled
out of the stove vent and replacement air finding it's way down the roof vent
stack and up thru the toilet.
Cure is to open a window somewhere while using the exhaust fan.

Donno why you get negative pressure when on the road.
Possibly you are getting positive pressure down thru the roof vent and that's blowing
the smell up thru the toilet.
There are vent toppers that have a venturi that sucks out sewer smell any time there
is a breeze. I assume these would also suck out the smell when you're going 60 MPH!!
Here's a link to one brand. They aren't cheap but folks say they work great.
Xtreme Plumbing Vents for RVs - Venturi Action - PPL Motor Homes

Good Luck!

[45 ACP]

Wow, those Xtreme vents are some serious $$. They are made out of aluminum though..........

Here are some other lower cost options.

Camco Mfg Inc - Cyclone Sewer Vent - Vents - Camping World

I just installed these on my 5'er and while my experience with them is exactly one trip, they seem to do the job just fine. Some nominal bushwacking in the campground while parking didn't seem to affect them at all.

Home | 360 Products Inc

Had I known about these, I probably would've gone this route as I like the lower profile.

[Ovair]

Since it is a toy hauler it makes me think there might be side vents? I had a toy hauler that had vents so that gasoline fumes didn't collect. However, the slipstream of air over the camper's surface causes a low pressure area much the same as a wing causes lift. That low pressure "MIGHT" be pulling air out of the camper which is being replaced by air being sucked into the toilet vent, down the tube, into the tank, and up through the commode into the living space. Convoluted, yes.
Remedies:
Close the vents while rolling
Open a forward vent to allow the air a path other than the vent tube
Install a cyclone

That is my .02!

[soccerloco]

Want to thank everyone for their fast responses. It makes sense. Today we traveled about two hundred miles with closed vents and no smell. My wife wanted to blame me but I insisted that my contributions to the black tank involved no odor.

Thanks
Bill

[showtime0022]

Lol ... Smell like roses, right lmao. I have Stealth and I installed the Campo Cyclone. It was cheap and easy to install. You can buy them at Wally mart for under 20 bucks.

[Malco]

We could smell sewer gas in our trailer the first few times out and someone told us it is because the traps lose the water in them for some reason while traveling.We now travel with the drain plugs in and no longer get the smell.

[dennis5_0]

We had the same problem with our Surveyor Hybrid, we had the vents closed and when we would haul the TT it would smell just awful. I would get it home and open everything to clear out the smell, I would even make sure there was water in every trap we had and still that stink was there. We ended up trading the TT for a Tracer but never did figure out why the smell was always there.


Dennis