Newbie question!

Two things today I wanted input on…sink trap and water heater vent pipe…

Concern or no? The vent pipe is double wall pipe as it penetrates the ceiling and there is over 6 inches on all sides from wall board.




Welcome Tim!

The trap “may” be an issue. Got another pic from the left side?

Assuming the ID of the flue pipe is constant (single wall/dbl wall), I see no issue.


That’s the only angle I got. It is what I would describe as an “S” trap, even though it’s not a typical straight “S.” It appears to be done for clearance issues inside the cabinet. Should I note it as a major or minor concern?

I woudn’t describe it as either (major, minor defect) but instead would explain the possible consiquences leaving it as is. Judging from the photo the client may just need to extend the fixture tail piece down a few more inches thereby lowering the trap bringing it more inline with the vent, then you would actually have a trap arm.

But of course this depends on how much room is between the trap and cabinet floor.


You could call the drain configuration as unusual and defer or just recommend replacement.

I would be a little concerned that the flue interior diameter changes in size in the transition from single to double wall.

an extension tailpiece on the sink drain would have allowed for a more conventional trap set up i saw no major issues on the hwtvent…jim

Thanks for the responses. I noted it as an “S” that needs attention/replacement. The HW vent I didn’t not draw out, other than to emphasize keeping combustibles out of this area! (ie "Don’t lay your laundry on it to dry!!!:shock:)

Thanks again, great to have a place for these newbie quesions until I get more comfortable making the calls on my own!

The drain is effectively an S-trap and should be replaced.

The single wall portion flue pipe may be too close to the combustible wall.
Do you have a dimension?

Good call on both items.

As mentioned, previously a tailpiece extension will allow reconfiguring of the trap.