The question is straight forward.
what is the relationship of the BOTTOM of the trap for a sink to the line coming out of the wall.
If its lower, then when in use, water coming down from the sink has a greater hydrostatic head than the short distance from the bottom of the trap to the bottom of the line going out. About 2 inches max.
But I have an A/C line that also feeds into the column above the trap, and because of the way the stub out ends, with no way to cut off and reduce the distance from the trap to the thread on, I have to snake some extra pipe to make ends meet. I dont want to use that bellows type connector, other issues there.
So, can the bottom of the trap be higher than the line going through the wall, equal, or is there NO difference, since the nature of the trap is secure with the offset that it has.
My concern with it being higher is that the water coming down from the sink would create a siphon that would clear the trap, making it a vent and not a trap.
As far as a vessel sink goes, I already have the right hand sink in, this is the left handed one.