Originally Posted by Jim Foster
Whatever type of seal at the bottom of the toilet bowl, it should seal well enough to hold water. Leaving some water at the bottom of the bowl will insure that no black tank gasses are coming back into the trailer from the black tank. If they are, there should be bubbles in the water at the bottom of the bowl.
If your gray tank valve is left open, and there is no "U" in the slinky hose, gasses can come in from your sewer connection unless you shut the gate valve on your gray tank. Even with that valve open, the "P" traps, if they have water in them, should keep odor out.
We have never had that problem either in our Caravel
or our Excella.
Thanks Jim .... I did find that when the a/c was on high for some time there was a negative pressure in the stream. If I hit the pedal it would immediately pull in sewer gas into the a/c and blow it front to back from the a/c, no smells anywhere else (closet, under a/c, bathroom).There must be a way it's pulling from the exhaust vent pipe, since I added a 2 foot extension and the problem stopped immediately (can't drive down the road that way). For the naysayers, it's hard to argue it can't happen, standing there with the a/c blowing in my face, flush the toilet and instant stink coming from the a/c
, not from the toilet or bath area, and I mean instant, like a shot out of a cannon. If I shut off the a/c and flush nothing smells, wait 3 minutes and start the a/c up again and clear air.