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dorn 02-03-2008 07:20 PM

Vent problem?
I live in one of three units on top of a commercial space. The building is about twelve years old. We have two toilets both of which have to be flushed twice if there are any solids. Our neighbours also have a similar problem. One interesting thing we have noticed is that flushing one toilet cause the water in the other to bob up and down slightly. I was wondering whether there is a vent problem, not enough slope on the waste line or what. All three units are vented separately. What would be our best way of determining what the problem is?
Thanks in advance for any assistance in this matter.

guyod 02-03-2008 09:14 PM

I agree with your assumption that its venting.. the only easy fix i can think of is if you have access to your vent to look down it with a flash light and look for any blockage.. . But since your neighbor has the same problem and you have seperate vents its unlikely they are both blocked.. good luck

glennjanie 02-03-2008 10:59 PM

Welcome Dorn:
No, there is no problem with the vent. Any change in atmospheric pressure in the building will make the water move, such as opening, or closing a door or even a change in the wind outside.
The toilets don't flush because the federal government in all their wisdom began requiring all toilets to flush with 1.6 gallons of water. Every manufacturer couldn't keep up with the technology. If you had a later model toilet it could preform much better. I have seen one of the newer ones flush 30 golf balls in one flush. Then the Japan model's salesman stopped me one day and declared with much pride that he had the Toyo which could flush 15 golf balls. I hated to break his heart but he made me repeat it 3 times; 30? three-zero? twice what mine will flush? It wasn't a pretty sight.

guyod 02-04-2008 08:09 AM


Originally Posted by dorn (Post 15518)
One interesting thing we have noticed is that flushing one toilet cause the water in the other to bob up and down slightly.

I don't see how Just a weak flush would cause this? More flushing power probably would compensate for the poor venting and might be the easiest and cost effective fix.. but it still seems like a venting issue..

travelover 02-04-2008 12:09 PM


Originally Posted by glennjanie (Post 15524)
.................... I have seen one of the newer ones flush 30 golf balls in one flush. ...............

I feel sorry for the guy that swallowed the 30 golf balls........ :D

inspectorD 02-04-2008 07:01 PM

Poor golf balls.
The more powerful flush will never help a venting issue.
Take a straw and put it in a glass. Put your finger over the top of the straw. Take straw out of glass.
The water stays in because there is no vent...remove your finger ..and the water leaves the straw.
Try again,,, this time try to suck the water out of the straw...wont happen.

That was just for folks to understand venting.

I have to lean on the low flush side....or they have kids with toy's and imaginations who once lived in the building.

Anyone loose a tooth brush.:D Ploink

guyod 02-04-2008 10:37 PM

That is not a good example of household plumbing. The pipes are to wide and there is places for air to escape under pressure for example air bubbling out another toilet..

a better example is emptying a jug of water.. water comes out in blurps because its gasping for air. you poke a hole in the top the water comes out faster the bigger the vent hole the faster the water will come out. If you sqeeze the bottle you can get a burst of water because of the added pressure. The water will always come out of the jug though.. And the more pressure you add the faster the water will drain along with the air finding a way to escape..

Be Careful when saying never

inspectorD 02-05-2008 06:19 AM

Ouch... then we need a better example...
That's it ...I'm going to straighten out that old tymer that gave me the analogy.;)
Your right, I will never say never again.:D Unless I really have too.
What I need explained is this...I built a large home for someone, the toilet on the third floor kept backing up and overflowed...not good. We snaked it, took it apart and changed the ring. Same issue.
The reason turned out to be the plumber. When he tested the DWV lines , it was winter. He never took the cap off the plumbing vent outside. Since this was vented by itself, it was the lack of air which caused the issue. The plumber removed the plug...presto chango..a workin cammode. I would think it would have drained from the sink or somewhere else, but the way it was plumbed did not. This was an older type power flush, so maybe that made some difference...only 15 balls instead of 30..could not say for sure.

So It does work for household plumbing also, sometimes, under certain circumstances....but I see where you are coming from also. :)

glennjanie 02-05-2008 04:28 PM

O K Justin and Bubba, go to your corners for a time out.
Believe it or not the book (National Plumbing, Heating, Air-Conditioning Association) uses the straw for the vent example. I taught that course for 2 years as a part timer and then for 8 1/2 years as a full time Assistant Professor granting Associate Degrees.
I also remember my high school Physics class (hard to have a chemestry/phisics lab in a one room school) we filled a big mouth jar with water, put a handkerchief over the mouth, turned it upside down and the water stayed in the jar. Mr. Manders said it was atmospheric pressure, or something like that; you know the same stuff that makes a water pump work.

I still say there is no problem with the vents in the building in question. If there were a problem, like Justin said, there would be 'blurbs' in one of the other drains; we are only talking about water movement here. Now, if you two can play right you may leave the corners.

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