This has probably been discussed somewhere, but I could not find it... so here it goes (I apologize in advance for the elementary nature of the attached images):
I have three new vanities and one new tub to install but have space constraints for the traps that need to go in. The drain from the wall is just above the bottom shelf of the vanity - effectively making it impossible to place a standard trap without cutting the vanity. So the question is this, can a p-trap be installed above the wall drain and have two 90 degree (or 45 degree) elbows route the water down into it from the trap? See the attached image figure A for a better visual
Also, with respect to "p-traps", typically the drain goes straight down into the U part of the trap. Then the flow goes back up until it hits the 90 that sends the flow horizontal. Does it matter what angle that horizontal extension comes off the U portion of the trap? Can it go back over like a loop or is this a big "no-no" for some reason? I would love some explanation on this subject because one guy told me that it makes a difference whether the final bend in a P trap goes straight back vs left/right/over... I don't understand the physics of why that would make any difference, but maybe someone can shed some light on it for me. See figure B and C for a visual. I would like to use the "loop" option (figure C) for the tub trap. Does anyone see an issue with this?
If anyone can refer me to some technical literature, that would be helpful too.
Thanks in advance