I think I remember reading about a WDV vent device that could be mounted inside a wall, and take the place of a vent stack in extreme situations where there was no access for a standard vent to the roof. I was wondering if anyone else has heard of such a device, where to get them, whether they work, and whether they are legal. My guess is that it is a one-way vacuum breaker valve that allows air in if there is a vacuum (such as when the sink drains and the plug of water going down the pipe tries to siphon the water out of the trap) but seals under all other conditions to keep sewer gasses in the pipe.
I do know that the vent stack is the correct way to go if at all possible. Any help would be appreciated.
–King O Topanga
Replies
As far as I know you still have to have acess to those kinds of vents. -----Although I have one covered with drywall and it works, but is non code worthy.
Have you thought about a loop vent? I just put one in a house today, because of a extreme situation. We ended up venting a tolet and a sink on the other side of the house by making a loop separate from the drain, but still connected to it. The loop is higher than the basin hight.
Go to a plumbing code book and it will tell you how to build one, It's a bit more PVC/ABS but they work great.
jason
Can use a loop vent to vent a toilet? The only place I have seen it used was on island sinks.
Yeahh Uhhhhh
Well, were doing this project on the sly and I' really don't know if you can "code" use them for a tolet, but it works great, I just tested it. When you flush the vent (which tommarow will be out the roof) sucks air like a vacume cleaner.
jason
Thanks. I've not heard of a loop vent, but I'll check it out.
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Island sink venting is only for sinks http://www.masterplumber.com/Laws/UPCExcerpts.html
A "Studor" vent is allowed on single fixtures, Not a toilet-You must also have a regular 3" stack through the roof elswhere in the system.
The srudor vent also must be accesable.
Thanks. Just what I need. It is a lav, and I think the toilet is vented, altho I need to check that. No money or time for reworking the tile floor, walls, tile roof, etc.
A lot of inspectors won't allow them.
No inspector has ever seen, or ever will see, this job. She just wants a bathroom that doesn't smell like a sewer. Anything we do will be an improvement.
The one way air valve is just that - one way - pressure in the drainage system will bubble the toilet and wet your tail. I hate burping toilets.
Good point. But, in this case, the pevious "plumber" vented the waste line outside with 2", so, although totally ineffective against siphon problems, it will relieve pressure and, I think, keep tails dry.
Codes change everywhere you go but most places those vents arent legal and the reason has been mentioned one way only. You can cause a vacum lock. Guys put these on pumps and they dont work. The loop is one way and in most areas if its a sink you just need to increase the drain to 2 inch and the trap with no loop and you are ok but only if you cant vent other wise vent it. Some areas you do the same withe the 2 inch but you must pull a vent up somewhere else within 8 feet still no loop. The big question is why you cant vent. If you get a code book it will show you how to do it with no vent. Im not sure about the latest book but in the past it did not involve any kind of loop.
There is no inspector, now or ever, on this job, and no money to rip out the finished walls, floor, ceiling, roof to put in a vent. I was hoping for a quick fix. Thanks for the reply.
-KOT