Gross Sewer Gas Smell

[lucca]

2016 Franklin. I have bad odor coming from under the bathroom sink

Any input would be appreciated.

thanks
lucca

[Lloyd]

Mark had this posted on another thread. Maybe you have the same issue.

Quote:
Anti-Siphon Trap Vent Devices (ASTVD) Another type of vent is the anti-siphon trap vent device. These handy gadgets are used as a secondary vent to aid in draining sink fixtures. Also called “check vents,” ASTVDs allow air into the drainage system, but prohibit air from passing out of the system. ASTVDs are installed in the liquid drain piping system, at or near a P-trap inside a cabinet. Look under the kitchen and lavatory sink area and you should find them. They are mounted at least 6-inches above the P-trap’s horizontal arm. ASTVDs do not allow odors to escape into the living portion of the RV because of an integral atmospheric pressure-controlled, rubberized, one-way valve. In other words, air in, but not out. If they leak air out, you will smell sewer gas.

[harley]

This could be your problem , the flapper could be staying open, they just unscrew. If there is one,try taking it off and swapping it with the one under the kitchen sink or buy a new one. they are less than $10.

[lucca]

I replaced the Anti-Siphon Trap Vent Devices (ASTVD) this did not help at all. will
look for any other valves. Could the P-trap be too short??

thanks

[harley]

re reading the symptoms , try looking for your black tank flush hose from the black tank to the anti-syphon/aerator . If you never used your tank flush there is a good chance that the hose is not connected thus letting poop smell into the cabinet. Dealers never check thes things on a pdi and factory guys do not tighten them properly.