the existing ss connection is out of floor for kitchen sink. p-trap is higher than sewer connection but the p-trap is still higher than the connection to sewer. Sometimes it smells like bad, could this be a vent stack issue and if so how to test vent stack?

messy existing

looks all wrong should i rip out old abs and start over?

  • Looks odd since they put in some extra pieces to make everything line up, but it isn't wrong. Any smell problems are indeed likely to be a vent issue. – keshlam Sep 7 '14 at 17:05

Yes, it's an effective S-Trap.

S-Traps are known for siphoning and new construction only allows P-Trap installations. You have a long horizontal run after a P-trap that prevents the siphoning effect.

The outflow on an S-trap is a straight drop which under high flow conditions can allow more water to be drawn out of the trap than is needed for a water seal, hence the sewer gas.

The short term solution is to allow the sink to completely empty, then run a quart of water down the drain afterwards to make sure there's enough water down there.

The long term solution is to figure out how to re-plumb so you can install a P-trap.

On checking the vent stack, I've had to run a long pole down them to clear out paper-wasp nests.

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It looks like there is 4-6 inches of horizontal run after the trap and it's a size up from the drain size, so I'm not so quick to blame the S-trap effect, but it's certainly a possibility. Where is your vent? It may simply be too far away to be effective and you'll need to install an air admittance valve.

You may also try to snake out the pipe between the trap and the vent. With all those bends (no sweeps!), you are bound to have all kinds of buildup which will effectively decrease the pipe diameter and encourage siphoning.

You can usually hear siphoning. If you hear a glug-glug sound when the sink is finishing draining, then yes, the trap is not working.

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