Tight space trap arm question

[dlarrivee]

Exactly, it would have been fewer fittings too.

[hdb]

I agree. There's a header above that small bay to the right, and I can't penetrate through it for obvious reasons. What I can do... is exactly what you're saying -- moving the combo fitting into the right bay, and then venting up and eventually 45 the vent back in to the bay above the washer box. Thanks for the good points. I'll post a picture when I'm done.

That wall isn't CMU, it's a product call rock lath. It was used, around here, during the 50's. It's a 1/2" gypsum board with holes in it, came in 16" widths. It was ran perpendicular, and then it was covered with 3/4" of concrete. Plaster was textured on top of that for the finished product. It's the in-between from lath and plaster to drywall.

[hj]

quote; I have failed literally hundreds just like that and so has every inspector in the region.

From that statment, I have to assume you are a city plumbing inspector, and if so, HOW can you not know what a 3/4 "S" trap is? When I was an apprentice, we had a neighboring city's plumbing inspector working for us. I fired him because he did not know what he was doing. When you got a few beers into him and asked him about apprentices, he would bemoan the fact that "He has been a plumber for 25 years, and some apprentice fired him".

[Tom Sawyer]

I don't inspect anything anymore but that particular configuration has come to be known as a 3/4 S, why I can't tell you. Technically it is not, and neither is it a true S trap but it is an illegal trap because you need 2x the pipe diameter between the weir and the inlet and there ain't anything near 2 times the diameter there.

[hj]

IT does not even approximate a 3/4 "S" trap, nor does it approximate an "S" trap. It is a "reach" to even consider it capable of siphoning under ANY condition.