Venting Plumbing

Discussion in 'Shop Talk' started by Terre d'Esprit, Nov 27, 2004.

  1. Terre d'Esprit

    Terre d'Esprit Boer-ing Mom

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    Our house has plumbing that is not vented. It's an old farmhouse, and the plumbing was added long after the house was built. We only have one bathroom, and the kitchen sink runs on a different line. At the moment, I'm here smelling the most awful smell of sewer gas, and can't take it one more minute (not to mention the health hazard that I am well aware of). So I need to vent the plumbing. There are no such things as buildling codes out here, so I just need it to work properly! : )

    The main waste stack down and out starts at the toilet. It's a 4" pipe straight down. Everything else feeds into it (the washing machine, sink, and bathtub drains) just below the top. There really is no place for me to vent it, other than below where the drains feed into the main stack. Is that okay? The vent will be lower than the drains feeding into the stack. Since the pipe starts with the toilet pipe, I can't vent it up from the top of the stack.

    We would also like to take advantage of an old chimney that we are not using in our basement. Can we run the PVC vent pipe over to the chimney and seal it up, and use the chimney for the pipe up and out? The other option would be to drop a long length of PVC down into the chimney and have it meet up with the pipe in the basement, but if it is unnecessary, we'd like to not do that. The chimney was used by the former owners for a wood stove, so we assume it is in relatively good shape (we have lived here for only 6 months).

    Any and all advice would be greatly appreciated!! Thank you in advance.

    T
     
  2. TennOC

    TennOC Member

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    If there's a smell, you need to first check to see if there's a trap under the toilet. I'm assuming you have P traps under sinks too. Their purpose is to hold a little liquid and stop the gasses from entering the house from the septic/sewer system. I would put the stack as close to the commode as possible.
     

  3. Terre d'Esprit

    Terre d'Esprit Boer-ing Mom

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    By trap, do you mean a P trap? There is nothing underneath the toilet except a straight pipe into the basement floor. If nothing else was drained into that pipe, it would be a 4" straight pipe, from the bottom of the toilet down into the floor. Now, as I said, they put a bunch of y fittings into the 4" pipe to allow the drainage of the tub, sink & washer. It looks like a big ol' tree, and the "trunk" is the drainpipe for the toilet, with everything else feeding into it.

    The other drains have the P traps underneath them (sink, laundry & tub). However, when any of them drains, it creates a vacuum which sucks the water out of the P traps of the other drains. The smell then comes into the house. the only way to avoid that is to run water in all of the drains, but that is a pain, and you can't completely avoid the smell.

    Thanks for your reply!

    T
     
  4. Beeman

    Beeman Well-Known Member

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    You should be able to vent it anywhere in the 4" pipe or anywhere in any of the other lines that feed into it. You shouldn't smell anything if you have correctly installed P-traps as someone else stated. The lower part of the P-trap fills with water that doesn't drain out and blocks any gases from coming back up the drain. If you had correct traps and used a drain you should have trouble getting the water to go down the drain with out it bubbling up into another drain if it isn't vented. Obviously this is ASSuming that all of these pipes run to a properly operating septic system. If you do run the pipe out of the chimney you will probably have to put a boot or cap to seal the chimney or the smell will sink down the chimney.
     
  5. agmantoo

    agmantoo agmantoo Supporter

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    Here is a vent that can be used in plumbing where there were no previous vents.
    http://www.plumbingsupply.com/autovent.html

    PS I imagine that the odor is coming through the drain traps that have the water sucked from them since you do not have a proper vent.
     
  6. insanity

    insanity Well-Known Member

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    When i re-plumbed an old farm house we lived in i just vented it with a peace of 1 1/2 inch pipe under the house(straight up to the floor boards).It just has to be higher than any of the other pipes coming into the main pipe.But that wasnt the line the toliet went into.Humm i dont think it would matter but i might be wrong. :eek:
    I wanted to knock a hole threw the foundation and run it up the back of the house but never got around to it.If your septic system ever gets full the vent pipe must be higher than the water drains in your house or it will over flow out the vent pipe under the house.and you will not no about it until it stinks bad enough under there. :eek:

    I had wondered why they vent them.Figured it was to release gas.Never though about it also sucking the water out of your pea traps.But i can see how that might happen.
    You toilet drain pipe should work fine with out a Pea trap.theres a trap built into the toilet.
    Did some one say Pea Trap! :haha:
     
  7. John Hill

    John Hill Grand Master

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    Hmmm! I have a little trouble visualising just what is going on!

    You say that draining the tub (or whatever) creates a vacuum which empties the traps on the other lines? I think for that to happen the 4" line would have to be filled by the outgoing water but I cant imagine even the washer delivering water in such a gush. Is it possible that the lines have too shallow a fall? The water can then fill the pipe completely and as it drains away empties the U bend? Other than rerouting the lines the answer would appear to be a vent on each U bend, this would not have to be much, maybe only a 1/2" hose fitted from a hole drilled in the top of the U bend with the other end outdoors above the maximum water level in the tub (or whatever). You could try it on one and if that particular U bend trap always held its seal you could do the others.

    You did not say the toiled loses it's seal and surely it dumps a bigger gush of water than anything else? Makes me think fitting a vent to the toilet would miss the problem.

    Just my thoughts on the matter.
     
  8. Yankee1

    Yankee1 Well-Known Member

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    To stop he smell you will have to add traps to all drains sink, tub/shower. The toilet will not need one it is built in. You could add a 4" trap or what ever size line you have going to your septic that would do the trick also. The vent comes into play by not letting the water be sucked out of the trap, you could get an inline vent and install it fairly easily as long as your drain pipes are PVC.
     
  9. desdawg

    desdawg Well-Known Member

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    If you have cabinets on an exterior wall, kitchen sink, lavatory, etc. sometimes you can install a tee where the drain connects, come off the top of the tee with a vent to the outside. Run the vent up the outside of the house above the roofline and paint it. Not the prettiest but it works.
     
  10. agmantoo

    agmantoo agmantoo Supporter

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    Each drain needs a vent within 42 inches of the drain (Plumbing code) to prevent the escaping drain water from siphoning the water that is used in the traps to prevent backflow of sewer odors. Use the device I referenced in the site posted above.
     
  11. joan from zone six

    joan from zone six Well-Known Member

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    the under counter vents that do not go to the world outside work well, are inexpensive and easy to install - no reason several couldn't be used - as far as toilets are concerned, the water in the bowl is the p-trap -
     
  12. Terre d'Esprit

    Terre d'Esprit Boer-ing Mom

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    Thank you all for your advice! :worship: Agmantoo, a week or so ago I saw the vents you described, and considered them, but wasn't sure how they worked. I checked our local hardware, and they didn't have them. However, I spent an hour at Home Depot today, and between checking out how everything works and talkign with the clerk, I think I have a plan.

    I will use the under-sink vents to begin with. I am not sure if the P traps are conducive to installing them per the specs, so I might need to go and do some work on the P traps before I can install the vents. However, my DH is a little scared of me reworking the entire stack, so I will appease him by starting there. At least if I screw something up, it will only be one thing (sink/tub/washer) at a time. :haha:

    If that doesn't work, then I will consider adding a vent near the top of the stack. But if the under-sink ones work fine, then it seems the path of least resistance.

    Thank you, thank you, thank you all!

    T