I’ve read that s traps that drain straight down are ‘bad’. With an island, thats the only way to do it. Do I p-trap into an ell that turns downwards? And, if my trap is roughly 8 feet to a horizontal drain that’s well vented, will I run into venting problems? The island has the main washing sink as well as a dishwasher. I hope I’ve given enough information clearly. Thanks in advance.
Neil
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there are a few ways they let us build "non vented islands" here that i'm aware of...
1. is considered a branch and can only be 5ft from the vent stack
2. is to oversize the drain so that there is no way to fill the pipe so as it acts as it's own vent... for you that'd be a 3" waste from the island to a 3" vented waste line...
they use to let us use a "volume of air" but not any longer...
might be other ways but thats what i know
p
Chect into air admittance valves also known as Studor vents.
Without doubt a real plumber will come along and reply, but consider this
http://www.rd.com/content/openContent.do?contentId=19540 - 75k
That's a good example but I would put another accessible horizontal CO at the left end of the vent arm before it turns vertical. In the case of a street back-up or line blockage, the horizontal pipe could become blocked with solids.
It couldn't hurt. With a history of living in older houses, with older plumbing, I've come to really appreciate having more, rather than fewer, cleanouts.
P-trap into a tee. The bottom of the tee goes down like a normal drain. The top of the tee connects to a loop that rises as high in the island as possible (ideally into a backsplash or some other space that's above the main island surface, then goes down through the floor, where it ties into a vent stack.
Sounds like the "U" on the downturn of the loop and then up into the wall vent pipe will collect condensed water- thus shutting off the vent. The diagram in the previous post is one of the better I've seen (but with another CO).
Any vent pipe serving a sink P trap must rise at least 6" above the flood rim level of the sink served before it can travel horizontally (well with a slight upward slope for drainage of condensed water). This rule is so that if there is a drain blockage, no water/solids from the sink can back up into the horizontal section of the vent pipe where hidden blockage may occur. The horizontal section of the vent pipe in the diagram is subject to blockage from sewer back-up or drain blockage and as such should be accessible to check or clean.
There is no downturned U in the vent line.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
There is no downturned U in the vent line.
OK So this is actually another variation of the diagram with a vent stack rather than a vent pipe with a potential "U" as in the diagram- the little joiner pipe from vent loop to drain is designed to get rid of condensed water there.