08-02-2014, 07:03 PM
It was obvious that we were pulling odors from the holding tank into the coach while driving. I did all kinds of looking for obvious leaks and breaches in the system but found nothing.
Then a long ago thread about vacuum breakers came to mind. The vacuum breakers, or air admittance valves are after the P traps on the sinks. Their purpose is prevent the P trap from being sucked dry when dumping the tanks. The theory of the valve is that it only allows air to pass into the holding tank.
As an experiment, I went to all three sinks and taped the openings closed. Voila, no smell in the coach while traveling.
512 has the Max Air vents, not Fantastic Fan, so even with the vent louvers closed, some negative pressure exists in the coach while driving. It was enough to pull air through the dysfunctional vacuum breakers into the coach.
Then a long ago thread about vacuum breakers came to mind. The vacuum breakers, or air admittance valves are after the P traps on the sinks. Their purpose is prevent the P trap from being sucked dry when dumping the tanks. The theory of the valve is that it only allows air to pass into the holding tank.
As an experiment, I went to all three sinks and taped the openings closed. Voila, no smell in the coach while traveling.
512 has the Max Air vents, not Fantastic Fan, so even with the vent louvers closed, some negative pressure exists in the coach while driving. It was enough to pull air through the dysfunctional vacuum breakers into the coach.