Stink!
Ok I think I have a smelly gray tank. Bedroom smelled couple days ago so I put some water in washer drain tarp. Since we don’t have washer it seemed reasonable the trap dried out. Now it stinks in the...
Forum Discussion
The valve is in the cabinet under the sink. Trace the drain pipe and you will see the valve on a short vertical stub just after the P trap. You can just unscrew the valve and replace it with one from Home depot or Lowes.
This is a one way valve that will allow air into the drain pipe, but block air and therefore odors from coming back up the pipe and into the RV. By allowing air into the drain system just after the P trap it breaks any siphon effect from the draining of the sink. Without the valve the standing water in the P trap could get siphoned out and allow odors to come back up through the drain.
For what it's worth your stick and brick house also has a feature to break the drain siphon and prevent draining of the P trap. But on a house there is no valve, just a pipe sticking up through the roof. Since we don't need additional holes in our RV roof we use the valve.
This is a one way valve that will allow air into the drain pipe, but block air and therefore odors from coming back up the pipe and into the RV. By allowing air into the drain system just after the P trap it breaks any siphon effect from the draining of the sink. Without the valve the standing water in the P trap could get siphoned out and allow odors to come back up through the drain.
For what it's worth your stick and brick house also has a feature to break the drain siphon and prevent draining of the P trap. But on a house there is no valve, just a pipe sticking up through the roof. Since we don't need additional holes in our RV roof we use the valve.
