Smell from newly installed sink

[dale.slattery]

Hey! We have a basin that was installed by a contractor. They connected this basin to the existing piping in the bathroom. The previous basin had no smell, but this one smells like rancid sewage. It has a trap like the previous basin did, but for some reason this sink had a very bad odour when the previous one did not.

When you run the water briefly, the smell will go away, but then some minutes later it will reappear. I covered the sink hole with tape and we are certain that is the origin of the smell.

I have two hypothesis: 1) the p trap in the new sink is not installed properly / faulty and the smell is coming from the sewage outside up into the drain; or 2) the contractor dislodged some piping connected to this drain in the house below.

Any suggestions on how go diagnose the problem and remedy this smell?

 

[Geofd]

Not sure how that trap works but the inlet should be covered in water,so the sewer gasses can't come thru the sink drain we use what refer to as a " p trap or drum trap " if you research them you will see how the water prevents sewer gas from entering the sink side of the drain it .
It might be that the sink enter from the side and exits out the top ,I'd get the contractor back

 

[MicEd69]

It looks like a very expensive fancy P-trap that isn't vented. The water is flowing down the vertical line and is pulling the water out of the trap. The 90 elbow needs to be replaced with a sanitee with the top being routed to a vent line or an Air Admittance Valve installed at the appropriate elevation.

 

[MrInfoPhilly]

Would be better off Switching to a P-Trap., and maybe switching the elbow with a Sanitarty Tee with a Studor Vent on top

 

[dale.slattery]

Hey guys thanks for the help. Checked into this, and the issue was the pipe was not long enough, so therefore it was above water, allowing the sewer smell to come in. Now fixed with a longer pipe.