astontibs wrote:
Doug, you may be on to something and I am the 2nd or 3rd owner. Could the black tank cover the width of the coach? I have crawled under the coach to look, but all the piping and tanks are above the frame and covered with a non removable panel.
For the air vent people, I thought of that, but if it was a blocked air vent wouldn't it do it all the time? It only starts to have the air bubble right before it clogs.
The vent could be an issue, BUT, when you have a Poop Pyramid, that causes a splash back up the toilet also. I would try my advise first and then see if your problem goes away before you worry about the vent system. If NOT, then check the vent system. National installed all 3 tanks in the sub floor before the coach is built. Replacing any of those tanks is a major job if they are defective. Very few Nationals had the Fresh tank under the rear Bed. Doug
