Drains sucking air

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by spicoli, Dec 30, 2008.

  1. spicoli

    spicoli New Member

    Messages:
    9
    My basement at my house had 4 pipes comming out of the ground 1 for toilet 1 for sink, 1 for shower and 1 vent for the toilet. My problem is that all pipes "suck air" like if i hold a lighter to the pipe it sucks the flame in, what would cause this, also this has already been connected to a vent stack so what would cause the pipes to "suck air" and is this a problem
  2. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,607
    Location:
    Cave Creek, Arizona
    pipes

    That is what is supposed to happen. It is caused by multiple events, not the least of which is wind blowing across the top of the vent pipe. That is why you HAVE a vent pipe. If the air pressure in the house were lower than in the drain line the flame would blow backwards.
  3. spicoli

    spicoli New Member

    Messages:
    9
    So i have nothing to worry about?
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,607
    Location:
    Cave Creek, Arizona
    worry

    No. If the flame did nothing, THEN you would have to start worrying.
  5. spicoli

    spicoli New Member

    Messages:
    9
    Ok, so i have poured water down the shower drain, but i still have the same issue, does this mean i have no ptrap installed? also how far down the line can i add one? Could it be 20" down the run?
  6. SewerRatz

    SewerRatz Illinois Licensed Plumber

    Messages:
    1,705
    Location:
    Chicago, IL
    If the pipes are only roughed in for this bathroom and there is no fixtures on these the pipes should be capped. If the bathroom is finished and your shower drain is doing that yes it would mean they forgot to install the trap. Maybe a picture would help us.
  7. spicoli

    spicoli New Member

    Messages:
    9
    No pics for now, but the shower pan is in already, and the vent is connected to the main stack. the sink is not in, and the toilet drain is capped. I'll try to draw a pic. also, can i add a p trap further down the line, so i don't have to rip out the shower base?
  8. SewerRatz

    SewerRatz Illinois Licensed Plumber

    Messages:
    1,705
    Location:
    Chicago, IL
    The P trap must be directly under the shower base.
  9. spicoli

    spicoli New Member

    Messages:
    9
  10. spicoli

    spicoli New Member

    Messages:
    9
    The pic is older, the diagram shows how the pipes are now. Everything drains great, but i'm worried the lack of a trap, at least from what i can tell will be a problem in the future.


    PS, thanks for the help guys
  11. gardner

    gardner DIY Senior Member

    Messages:
    217
    Location:
    Ontario
    Has the water been connected up? Is there water sitting in the traps?

    Until water actually flows into the drain system and fills the traps, there will be free airflow between the vents traps and drains. Warm air from inside will rise up the vent and draw air in behind it.
  12. spicoli

    spicoli New Member

    Messages:
    9
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    Here are up to date pics of what's up, i just poured water down teh shower drain right before takin the picture so i'm f'ed i'd say since there is no p trap from what i can tell. Also, there is suction down the shower drain if teh toilet is capped, if it's uncapped, there seems to be no air suction down the shower drain. Does this seem right. Hope the pics helped, and it sounds like the shower base is gonna have to be broken loose and a p trap installed under the concrete?
  13. spicoli

    spicoli New Member

    Messages:
    9
  14. spicoli

    spicoli New Member

    Messages:
    9
    So the floor is up and the drain for the shower is a T into the 3 inch draining the toilet, which is upstream of the shower. Can i ptrap the shower and be fine or do i have to reverse the toilet and shower locations?
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