Home>Discussions>PLUMBING>Water sucked out of 2nd toilet, vent stack is clear
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johnjh2o
Re: Water sucked out of 2nd toilet, vent stack is clear

There is no picture.

John

vaulter825
Re: Water sucked out of 2nd toilet, vent stack is clear

Sorry, I tried uploading them and it didn't work. It wouldn't let me post a link since I am a new user..Let's see...

go to picasaweb[dot]google[dot]com/106874389684558484379/February222013#

dj1
Re: Water sucked out of 2nd toilet, vent stack is clear

Vaulter, I saw the photos.

I have a question for you: how is the copper drain pipe bonded into the PVC fittings?

MLB Construction
Re: Water sucked out of 2nd toilet, vent stack is clear

from what i know, which may or may not be alot, there is a vent clog somewhere. maybe you just can't find it. i can't think of any other reason why something like that might happen. i'd recommend having a plumber snake the vent from the roof to the basement or have a plumber with a scope run a camera down the length of the vent. i'll bet you that there's something blocking the vent somewhere, maybe an elbow or somewhere else.

JLMCDANIEL
Re: Water sucked out of 2nd toilet, vent stack is clear

Your problem is caused by not having a vent on the lower connection. When the toilet on the upper connection flushes it blocks the venting of the lower line.

Jack

vaulter825
Re: Water sucked out of 2nd toilet, vent stack is clear

I have also installed an AAV on the sink, which i ties into the same drain as the toilet (i think it is a 1.5"x3" wye). Did not do anything to help the problem...

Could it be something related to how close the 2 sanitary tees are to each other when they tie into the main stack? They are only abut 6" on center, which is 3" between the bottom of the main toilet drain, and the top of the other drain. Could this somehow be creating a siphon in the second line that even the AAV cannot handle?

JLMCDANIEL
Re: Water sucked out of 2nd toilet, vent stack is clear

Yes as the flush from above rushes by the lower line it creates a suction.

Jack

MLB Construction
Re: Water sucked out of 2nd toilet, vent stack is clear

either the vent is blocked or something is not properly vented.....end of story

guy48065
Re: Water sucked out of 2nd toilet, vent stack is clear

already covered....ignore.

Mastercarpentry
Re: Water sucked out of 2nd toilet, vent stack is clear

Vent the lower line before it enters the stack- you can tie the upper end back into the stack so long as that tie is above the upper line. I'm with JLMcDaniel on this one- the passing flow is creating a suction and without a vent, it will draw the water out of a toilet or trap. I've seen this several times and some kind of secondary vent is the fix.

Phil

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