wet venting sinks [combined posts]


  #1  
Old 06-25-05, 01:20 AM
Hendley
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wet venting

I am trying to understand wet venting. I have a bathroom sink, tub and toilet that connect together to one cast-iron waste pipe which also vents up through the roof. So, aren't these all wet vented? Why would one bother to connect indirect venting or some other system?

In addition, the bathroom sink also has an air admittance valve, it is probably a bad mechanical valve but may be a studor valve, I'm not sure). Why would someone have added this valve if as described above, the bathroom sink is wet vented? (I do get some sewer gas smell from this sink which I assume is from the faulty air admittance valve).

Thanks for the help.

Pete
 
  #2  
Old 06-25-05, 01:30 AM
Hendley
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how to wet vent a kitchen sink

I have a first floor kitchen sink that I have discovered has no venting whatsoever. It runs directly into a waste drain with no venting. This sink gurgles when water goes down, though I haven't smelled any gases from it and have had only one clog over the past couple years that I cleared with a snake.

In the basement, this kitchen sink's waste pipe runs vertically about 2 1/2 to 3 feet away from a PVC pipe for the washer which connects at the basement level to the house's main cast iron waste/vent pipe as a drain and then runs up to the second floor where it connects again to the main cast iron waste/vent pipe thus venting the washer.

Is it okay to connect the kitchen sink waste pipe across this 2 1/2 to 3 feet to the vent pipe for the washer, at an upward angle (not horizontally), in order to provide venting for the kitchen sink?

whew, that was hard to explain. I hope it is clear. Thanks for any help anyone can provide.

Pete
 
  #3  
Old 06-25-05, 03:15 PM
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Venting and especially wet venting is hard to understand, in principal. Code wise, almost impossible to interpret in some cases, when code official is standing there.

The very basic....the Uniform Plumbing Code and the International Plumbing Code are at the very opposites ends of drainage and venting. Both have charts that show the size of the pipe and the max. length of the developed run that is needed before venting is required.

In the case of your bathroom, the developed lengths are probably within the specifications for the plumbing code used during your home's construction. The AAV (Studor Valve) was most likey an afterthought. (you should probably replace it with a new one) Even though, the lav is wet vented.

The kitchen sink should not be vented in the mannor you suggest if the stack you are tieing into has a toilet (or urinal) on it. You can not tie in lower fixtures on a waste stack like that. {tub or lav only on stack are okay under some codes} The vent you are wanting to install must be ran above the flood rim of the second floor fixtures and then tied into the waste stack.

You best bet, without a major rehab, is once again the famous Studor Vent installed under the sink and tied in the drain with a tee fitting after the trap. You would need to extend the drain arm by removing the trap adapter fitting and tie in the tee at that point. Then have the trap adapter attach to the tee. Then just shorten the trap arm by what is needed to get to the trap adapter. (hope this is clear)

Good luck with your project, more questions ask and someone may answer them.
 
  #4  
Old 06-25-05, 09:34 PM
Hendley
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thanks for the help. That clarifies it.

So, could I just remove the old mechanical air replacement valve and not upgrade it to the Studor and just leave it with the waste line which I assume means it is wet vented. (I don't really have room for the Studor valve). Thanks very much for your help.

Pete
 
 

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