Holding tank vent

[OKIE9ERS]

What's preferred method of venting black/gray tanks? 2" pipe through the roof?
Not crazy about the idea of drilling holes up there, or a pipe from floor to ceiling in the bathroom, but if that's the only way...?
Thanks

[Dave5Cs]

Our goes from the tank through the floor and then the roof with a vent cap. Have seen some vent out the wheel well area in the rear too. Mine is a 1-1/2"ABS And the grey "ys" into the black vent pipe so only one goes up and out.

[chessie4905]

through the roof. check all the rv's and tt's. they are almost all through the roof. when vented in a wheel well or such, there will be times where you will smell the odor. Hole? No big deal with all the other openings already. Change things up in the future? just add a patch with rivets or screws and sealer. Nobody would see the patch anyways, and I wont tell...

[richard5933]

I know that most modern RVs and TTs have a vent through the roof, but our combined gray/black tank has a single 1/2" tube which goes out the top of the tank, takes an immediate u-turn, and then exits out the floor of the bay. The bottom of the tube is cut at a 45-degree angle to promote suction as the bus moves forward. We don't have any issues with odor coming from the vent.

[Nova Eona]

P.O. on mine routed both vents to a PVC pipe leading to the battery bay on my 4104, with a cap included for storage.  Can't comment on the effectiveness in action yet, but personally I'd prefer the occasional whiff over an additional hole in the roof.

[dtcerrato]

IMHO if it's a bus, no body penetrations, if it"s a conversion/tiny house - go for it and do what makes it functional. Our 1953 in-service 4104 started getting converted by yours truly in 1979. There are plenty penetrations through both long sides, the roof, the wooden floor, the bottom bay aluminum floor, & through bay bulkheads, etc. No leaks and are all there for a purpose - including a roof air, solar arrays for house & chassis, & a host of upgrades and remodels along the way. AFAIC it was a Greyhound intercity bus, now! It's a GMC converted coach... That's our story & we're stikin' to it. It's truly comfortable self contained home where ever we park it...

[neoneddy]

Ours started venting out the floor of the wet bay.  Kept getting odor inside, eventually moved to the roof.  Only issue now is I put it too close to the vent .  Oh well. that's just exhaust vent now.

[Iceni John]

In order to ventilate the black and grey tanks with fresh air so the aerobic bacteria there can do their thing, I have a unique design.   Each of those tanks has two 2" vents on its top surface;  the black tank has a 2" vent pipe going up inside a closet and exiting to a forward-facing louver just below the roof gutter, both tanks are inter-connected by a 2" pipe, and the grey tank has a 2" vent pipe that goes down to just ahead of the differential and points back.   When driving, air is directed by the upper louver vent down into the black tank, across the tank and out to the grey tank where it again blows across and then down to road level where a rudimentary venturi pump sucks out all the stinky air at road level.   When parked the airflow is reversed, with cool air from under the bus entering the grey tank's lower vent pipe, passing through both tanks and exiting the black tank's upper vent, courtesy of natural convection.   So far, so good!

John

[luvrbus]

Geez guys you are venting for the methane gas just like your home not the odor .Passenger buses have a sealed tank with a suction fan to pull the methane gas from the tank,holding tanks have  lot of nasty gases that are lighter than air which means it rises   

[6805eagleguy]

We went straight thru the roof with a metal building boot, however under way it seems that it is pressurizing the waste tank. Not sure how to solve that problem

[Nova Eona]

We went straight thru the roof with a metal building boot, however under way it seems that it is pressurizing the waste tank. Not sure how to solve that problem

Put one of those spinning nose&fin things on top of it, that will ensure the wind passing it sucks outward instead of pushing in.  Had that issue on my old RV and that fixed it nicely.

[OKIE9ERS]

Thanks everybody!!

[buswarrior]

We went straight thru the roof with a metal building boot, however under way it seems that it is pressurizing the waste tank. Not sure how to solve that problem

Pressurizing the tank, or hurtling down the highway is dragging a vacuum on the coach interior?

Having the driver's toll window open when someone steps on the pedal... various busnuts have been able to splash the occupant of "the little room" ...

After spending time with the boat folks, i will put two large vent pipes into and out of the waste tank. Lots of air, no bad smells, little to no air, lots of bad smells.

The boat peeps have to manage this more closely, as they don't "dump" , they get "pumped" , so harder to send it all away...

Happy coaching!
Buswarrior

[Dave5Cs]

P.O. on mine routed both vents to a PVC pipe leading to the battery bay on my 4104, with a cap included for storage.  Can't comment on the effectiveness in action yet, but personally I'd prefer the occasional whiff over an additional hole in the roof.

Seriously? You might want to rethink this one. As Clifford said above that is Methane gas coming out there. Just takes a spark  and the right timing and batteries sometime have those kind of events.

[oltrunt]

I planned to block out the two rear 1/4 round windows and decided that they would make a good spot for venting the on demand water heater and holding tanks.  So far so good--no leaks and no stink.  Jack

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