Whole-House Trap

The purpose of a plumbing vent is to equalize the pressure in a plumbing system in order to protect the trap seals. That's it. There is no other purpose. It's purpose is not to "vent" sewer gasses.

(There is one specific, and relatively rare, vent that has another purpose. It is found only when using a whole house trap.)

The purpose of a trap is to prevent sewer gasses from entering the space. That's it.

(Again, a whole house trap may have an alternate purpose, but not always.)

Okay, so this is all anecdotal but,
it's my experience from being on roofs,
that the smell around the vents is
both more pronounced and more odiferous
when connected to septic.
Further, a house where we did a deck
was almost unbearable outdoors in the summer,
and the HO had a septic outfit come in to replace
clay vit line from house to tank with PVC.
They also put in what was descrbed as,
and appeared to to be, a trap and clean out.
When they finished it was much more pleasant
to work back there regardless of the wind direction.
Was that all voodoo?

Yeah, it was all your imagination.

Kidding!

I don't like to use house traps but it would do exactly what you described.

Thanks, that's why I thought that was their purpose.
I never thought about the un-trapped drain senario.

Welp, - - the guy came out today and cleared the lines. I wasn't there, - - I was out ordering her siding and windows, - - but she said the clog was indeed right at the house trap, - - he cleared it out for about $300. And then he suggested she get rid of both the house trap and the house vent and just run a straight line (for another $1000, - - which she didn't go for). Although that was my initial call, too, - - logic tells me that killer is right, - - how can you be sure everything has it's own trap??

A smoke test could clear that right up.

The job is done and the sh!t is flowing freely again, - - but you're on, - - how do you go about 'clearing' things up with smoke?? . . .


P.S. That $1000 would give her up to 3 more clean-outs, - - I figure probably a good 20 years at least, - - she's 73 now . . .

Cap off all the vents through the roof. Hook up a smoke machine (you can buy them made for this purpose) to the plumbing system (remove a trap at lav?) and let'er rip.

If smoke comes out into the house you know where there is an untrapped drain.

Interesting, - - I've never heard of that . . .

You can make your own. Pretty simple. PM me for a link if you ever need one.

It's (the vent) purpose is to act like a vent, the same as the vent on a gas cap or gas can, that's why they call it a vent.



Main Entry:
2vent
Function:
noun
Etymology:
Middle English, anus, outlet, probably from Anglo-French, wind, draft, outlet
Date:
15th century

1: an opening for the escape of a gas or liquid or for the relief of pressure: as a: the external opening of the rectum or cloaca : anus b (1): pipe 3c, fumarole (2): hydrothermal vent c: an opening at the breech of a muzzle-loading gun through which fire is touched to the powder dchiefly Scottish : chimney, flue 2: an opportunity or means of escape, passage, or release : outlet <finally gave vent to his pent-up hostility>
— vent·less Listen to the pronunciation of ventless \-ləs\ adjective


.

The PRIMARY purpose of a plumbing vent is to equalize pressure in a plumbing system in order to protect the traps.

It's PRIMARY purpose is not to vent sewer gasses. That may happen but that is not why code requires each fixture to be vented.

Thanks, - - I would never really need one myself, - - but the info you've given is great to know in case this ever comes up with a customer again.

Now it does make me curious if the guy was going to do a smoke test, - - or if he was just going to eliminate the trap either way.

Anyway, - - I will let her know that if she was ever to decide to get it done, - - to make sure they do that test . . .