2 town homes (units) sharing a wall, with 2 bathrooms upstairs having B2B toilets, one per unit per bathroom - for total of 4. Toilet flanges are literally 20" apart, draining into common vertical drains, one per pair of toilets
All the toilets are modern 1.3 Gpf types. In my unit, I have identical common ~$150 toilets, Kohlers.
Please refer to the diagram below.
The bathroom #2, on the right, both toilets ( one in ea unit), flush fine, no pull, no ripples. This is the bathroom that has vent stack going up and through the roof.
The bathroom #1, on the left, I have an issue. Either toilet (mine or one in the other unit), when flushed, results in water movement in the toilet on the opposing unit, with some loss of water. Even with water movement and pull, the toilets do flush, albeit less vigorously compared to one in bath #2 (and I have another toilet of same make/model downstairs - it flushes with more gusto as well).
The bathroom #1 has sink and toilet vents, connect to a horizontal run of may be 16', which then connects to the vertical vent in bath #2 - as shown in the pic below.
Had a plumber come in and he decided to snake the toilet in bath #1. Didnt help. Still very severe
loss of water in the "twin" toilet in the other unit. You could plainly see a big bubble come through the toilet as other was flushed.
I thought that the issue was related to clogged vent, classic vacuum pull. Since bath #2 is not affected, the plug in the vent had to be close to bath #1, or so I thought. Due to bathroom design, it is easy to get to the vent pipe. So I opened the drywall and cut a section of vent pipe (2"), directly behind the tank of the toilet (dark blue section in the picture).
I examined the resulting 20" or so, run of vent pipe with a boroscope and saw no obstruction. When flushed, I can clearly see the water rushing into the drain pipe.
But STILL, even with vent pipe cut open and LEFT open like that, I get the ripples and water loss in both toilets !
I placed some die into one toilet, didnt see it show up in the other, so it doesnt seem toilets shoot water into each other.
What could possibly be the root cause here ?
Will try to auger the drain in the bath #1 all the way to the horizontal drain pipe in the crawl space - about the only thing that hasn't been done.
Most plumbers wont even touch this job, as you could wreck plumbing for a number of units at the same time (in my case 5, thats how many empty into the same master drain pipe in the crawl space).
All the toilets are modern 1.3 Gpf types. In my unit, I have identical common ~$150 toilets, Kohlers.
Please refer to the diagram below.
The bathroom #2, on the right, both toilets ( one in ea unit), flush fine, no pull, no ripples. This is the bathroom that has vent stack going up and through the roof.
The bathroom #1, on the left, I have an issue. Either toilet (mine or one in the other unit), when flushed, results in water movement in the toilet on the opposing unit, with some loss of water. Even with water movement and pull, the toilets do flush, albeit less vigorously compared to one in bath #2 (and I have another toilet of same make/model downstairs - it flushes with more gusto as well).
The bathroom #1 has sink and toilet vents, connect to a horizontal run of may be 16', which then connects to the vertical vent in bath #2 - as shown in the pic below.
Had a plumber come in and he decided to snake the toilet in bath #1. Didnt help. Still very severe
loss of water in the "twin" toilet in the other unit. You could plainly see a big bubble come through the toilet as other was flushed.
I thought that the issue was related to clogged vent, classic vacuum pull. Since bath #2 is not affected, the plug in the vent had to be close to bath #1, or so I thought. Due to bathroom design, it is easy to get to the vent pipe. So I opened the drywall and cut a section of vent pipe (2"), directly behind the tank of the toilet (dark blue section in the picture).
I examined the resulting 20" or so, run of vent pipe with a boroscope and saw no obstruction. When flushed, I can clearly see the water rushing into the drain pipe.
But STILL, even with vent pipe cut open and LEFT open like that, I get the ripples and water loss in both toilets !
I placed some die into one toilet, didnt see it show up in the other, so it doesnt seem toilets shoot water into each other.
What could possibly be the root cause here ?
Will try to auger the drain in the bath #1 all the way to the horizontal drain pipe in the crawl space - about the only thing that hasn't been done.
Most plumbers wont even touch this job, as you could wreck plumbing for a number of units at the same time (in my case 5, thats how many empty into the same master drain pipe in the crawl space).
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