BKLaw wrote:
Deb and Ed M wrote:
Just a thought: was the ceiling vent open? I wonder if a slightly-open vent created a suction in the bathroom as you went down the road?? Might explain how the sink could have black fluid, without having the whole bathroom afloat in it? Or maybe the vent stack is creating pressure in the tank?
I know in our previous Class C, having the skylight vents open on the roof created enough suction, that black-tank odors were drawn into the RV unless we created equal pressure by turning on the dashboard air or opening a window. At least on a Class C, the tanks are farther below the bathroom fixtures (plus we seldom boondocked. The tank was usually empty when we traveled)
Yes it was, the one in the bathroom.... That might have had something to do with it.
It was explained to me, that the curved top of an open vent creates aerodynamic suction/lift; and apparently quite a bit of it! If the bathroom door was closed (surely it was while on the road) - then there's no way for air to get into the bathroom to balance out that vacuum, so in the case of a Class C, the air comes from the black/gray tank vent, back up through the drain pipes, into the room. Of course in a TC, the tank is much closer to the fixtures, so you actually got liquid.
Keep the vent closed, and see if it happens again on your next trip??
