1. Bob(not a plumber)

    Bob(not a plumber) New Member

    Messages:
    11
    Location:
    BC, Canada
    I am doing a little basement renovation involving a little bit of plumbing for a friend. His basement has a suite in it. This was added in long after the house was built. Part of the renovation we are doing is moving the laundry from one room to an adjacent room. When I pulled the washer outlet hose out of the drain, raw sewage gas filled the air, GROSS. I pulled of the wall paneling to see a 2 inch line coming off a horizontal drain on a 45 degree elbow stubbed out of the wall. No trap. I cut the line back in the wall, and added a 2" to 1 1/2" reducer, a trap and a drain running up the other wall for the relocation. Now the drain sucks air through the trap when any thing downstream in the suite is draining. You can here it bubbling in the trap. Obviously there are no vents in the suite, and it was using the washer drain as a vent. The next fixture downstream from the washer is a kitchen sink. Would it help to put an AAV under the cabinet between the wall and the p trap? I can see down the back of the wall from the laundry. The drain runs vertically from the washer all of the way down the wall with the kitchen sink teed off of it, and then it disappears at the far wall. There is no drop from the sink, to the drain, and no vents to be seen.
  2. Doherty Plumbing

    Doherty Plumbing Journeyman & Gas Fitter

    Messages:
    810
    Location:
    Penticton, BC
    You may need to add TWO cheater vents to the system. I am trying to picture what you described but it's not working out well for me :p
  3. Terry

    Terry Administrator Staff Member

    Messages:
    14,759
    Location:
    Bothell, Washington
    Every trap needs a vent. So count up how many plumbing fixtures you have, and that's how many vents you need.

    Simple.

    The vent is downstream from the p-trap.
    There are also distance limits on where the vent can be.
    If it's too far away it won't vent correctly.

    A. If you look on your roof, you will see pipes sticking out of the roof aprox 12" high. For every pipe that goes down, one needs to go up. The obvious reason we have vents is that sewer gases need to be vented outside of the dwelling. Not so obvious is what happens if they are not included in the waste and vent design. Imagine yourself at McDonalds drinking a soda from a straw. If you put your thumb over the straw, you can pull liquid up from the cup. Remove the thumb and see it instantly drain out! When liquid goes down a pipe, air needs to follow it. Without the vent pipe, the draining liquid will try to suck air through the P-traps on the plumbing fixtures,(tub, sink, etc.) glurp, glurp! If it manages to do so, you may know it from the "smell" coming from the now dry seal on the P-trap. Without vents, draining one fixture may cause another fixture in the house to back up, yuck! A waste and vent system should keep sewer gas out of the dwelling and drain every fixture well.

    Helpful Plumbing Hints for Residential Construction by Bert Polk Plumbing Inspector Lincoln County
    Last edited: May 24, 2010
  4. Doherty Plumbing

    Doherty Plumbing Journeyman & Gas Fitter

    Messages:
    810
    Location:
    Penticton, BC
    Well not exactly. You can wet vent things and save on venting. I find, through reading this forum, that our codes regarding wet vents are much more forgiving then down in the states. For example pretty much every bathroom built in Canada is wet vented through the bathroom sink picking up the tub then toilet last. So you have 3 fixtures with only 1 vent going up.
  5. Bob(not a plumber)

    Bob(not a plumber) New Member

    Messages:
    11
    Location:
    BC, Canada
    Thanks Doherty for the helpfull advice. I will look for somwhere to ad a second cheater vent. As for the lesson on how a proper system is designed please keep in mind I am working on someone elses mess, I know all about that stuff, but am not asking how to redsign the whole system. I am just asking how to make it better, or functional without spending too much money and time.
  6. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Trust me....Terry is a #1 proponent of wet venting, and I am sure he means you need venting on each fixture, but not necessarily 1 to 1 pipe out the roof. What we usually see here in S. Cal. is one pipe out the roof per bathroom, and sometimes 1 per two bathrooms if they are back to back, plus one from the kitchen, and the laundry is tied in wherever is appropriate. Wet venting the bathroom group is the norm.
  7. Bob(not a plumber)

    Bob(not a plumber) New Member

    Messages:
    11
    Location:
    BC, Canada
    I put an AAV under the kitchen sink and it seems to be working better. Upon further inspection the bathroom that is downstream is vented. The trap at the washing machine is not drawing air in, so although it is far from an ideal setup, I am OK with it. Thanks for the tips on venting.
  8. Terry

    Terry Administrator Staff Member

    Messages:
    14,759
    Location:
    Bothell, Washington
    Here are some ways fixtures are wet vented.
    The fixtures are on the same floor.
    You can't dump a bathroom or sink on the second floor into the first floor vents.

    [​IMG]
  9. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,245
    Location:
    Cave Creek, Arizona
    Many DIYers assume all you need for a "wet vent" is a pipe with water flowing through it. HOW you install the wet vent, (or any vent for that matter), is MORE important and often determines whether it is REALLY a vent or is merely cosmetic. Did I read that right that you put a reducer on the washer drain and used a 1 1/2" trap? And HOW did you convert from the 45 degree drain TO the trap? Did you put a VENT on it, which that description would have required?
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