supers4
New Member
EDIT: I should point out for code, I reside in Ontario, Canada(Its in my profile, but figured I should mention it in the post
So I recently replaced an old laundry tub for my mother in her basement. The previous one was from the 80s at least, and the fixture had been dripping for quite awhile(and only had hot, because the cold dripped years ago so my father capped it. Because oh yes, this fixture was sweated onto the supply line). So now she's quite happy she has working cold water again in the tub. I also added in an AAV as I didn't believe the basement fixture was properly vented(there are two roof vents on the house, so the system is vented). The issue that is arising is when the kitchen sink is filled to do dishes then drained, the p-trap in the laundry tub bubbles out. Which I assume means positive pressure in the system being generated. Removing the AAV stops the problem. But clearly that isn't a solution as that would mean an open vent inside the house.
As I said, there are two roof vents on the house, it is a split level house. One half has the two bathrooms and they share a vent, and then the kitchen has a vent. The kitchen is directly above the laundry room, the drain line from the sink comes through the floor then runs under the floor joists until it meets the next wall(it can't come straight down as there is a window there). Previously the only "vent" the laundry room had was I assume a "wet vent" as it used the drain line from the kitchen. Issue is years ago I had to do a repair as my father originally had the point where the kitchen and the horizontal line met as a T, and it cracked open. I replaced it with a wye in what I believed was an attempt to reduce the strain on the joint. Maybe that was a mistake? Did that suddenly remove it's ability to vent?
The new system has an AAV, which I thought would fix that problem. And it mostly has, in that the laundry tub drains quite well. The issue is when the kitchen sink drains from full(when you just run the water, no issues).
I've attached a diagram of the laundry room plumbing, and a very rough(and absolutely nowhere near scale) diagram of the house system. The two bathrooms on the left of the image are almost right on top of each other, and the vent runs basically through a shared wall in that area from what I know of it. There are no drain issues in that part of the house.
So would this issue mean, if there is a clog somewhere, it must be after the wye, but I assume before the junction where the bathroom stacks come into play? Bathroom stacks are 3" ABS, the lines coming from the kitchen and laundry room at 1.5". Or is the issue that the horizontal line where the kitchen and laundry room come together should be 2" until it meets the 3"?
The original idea for the laundry room was to add in a standpipe for the washing machine, but code required it to be a 2" which would have meant replacing about 20feet of pipe. Since my mother was just as happy to have it drain into the laundry tub as it always had, it was decided against changing out all the 1.5" pipe.
So my understanding is, I have positive pressure building up between the wye and the trap under the laundry tub. And so the only way to relieve it, is for the trap to bubble until the system balances itself(or the kitchen sink finishes draining).
Could the roof vent be clogged? Would that cause the problem in the lower floor? or could the drain line be partially clogged to the left of the wye, between the wye and the connection to the 3" line? Or am I missing something entirely?
This was a problem years ago, and the solution then was to install a leftover flow-valve from a sump pump behind the washing machine along the horizontal stack. It, worked, but when adding in the AAV that check valve was removed because it was full of soap gunk, and I presumed to think the AAV would solve most of the issues.
Hoping you guys might have suggestions or solutions to this problem. I do not have access to the kitchen vent stack, as it is buried in a wall, behind the kitchen cabinets. I do not foresee my mother agreeing to let me go on an adventure of ripping up her kitchen. She'll likely just accept that it's been like this for years, so let it be. Unless I can run a line to the right of the laundry tub, up that wall and tie it back into the kitchen drain(but I'm not sure if that would solve the problem, as it's just another wet vent, and might just cause the drain to divert itself at whatever fitting I use there?) Or maybe it is a clog, and I'll have to get my hands on a snake(and find or add in, a cleanout in that area. There is a cleanout on the horizontal line from the kitchen, then there is one at the 3" line. I do not think there is one elsewhere that I am aware of at least, not until the connection to the main sewer line at the far end of the crawlspace. If necessary, I could cut in and add one by the wye if the one in the ceiling doesn't work.
Edit2: So after looking at the plumbing coming down from the kitchen, I have noticed the horizontal run has a sag in it. This will be fixed shortly; but could this be causing the issue? It's a 5' run, but end to end difference is less then 1/2" drop, with the middle sag having about an 1" difference. My solution to fixing it is cut the vertical drop coming from the kitchen and shortening it. I'm not sure if this could cause the problem given it's before the wye. But figured the most pieces of the puzzle offered, the better odds of finding a solution.
So I recently replaced an old laundry tub for my mother in her basement. The previous one was from the 80s at least, and the fixture had been dripping for quite awhile(and only had hot, because the cold dripped years ago so my father capped it. Because oh yes, this fixture was sweated onto the supply line). So now she's quite happy she has working cold water again in the tub. I also added in an AAV as I didn't believe the basement fixture was properly vented(there are two roof vents on the house, so the system is vented). The issue that is arising is when the kitchen sink is filled to do dishes then drained, the p-trap in the laundry tub bubbles out. Which I assume means positive pressure in the system being generated. Removing the AAV stops the problem. But clearly that isn't a solution as that would mean an open vent inside the house.
As I said, there are two roof vents on the house, it is a split level house. One half has the two bathrooms and they share a vent, and then the kitchen has a vent. The kitchen is directly above the laundry room, the drain line from the sink comes through the floor then runs under the floor joists until it meets the next wall(it can't come straight down as there is a window there). Previously the only "vent" the laundry room had was I assume a "wet vent" as it used the drain line from the kitchen. Issue is years ago I had to do a repair as my father originally had the point where the kitchen and the horizontal line met as a T, and it cracked open. I replaced it with a wye in what I believed was an attempt to reduce the strain on the joint. Maybe that was a mistake? Did that suddenly remove it's ability to vent?
The new system has an AAV, which I thought would fix that problem. And it mostly has, in that the laundry tub drains quite well. The issue is when the kitchen sink drains from full(when you just run the water, no issues).
I've attached a diagram of the laundry room plumbing, and a very rough(and absolutely nowhere near scale) diagram of the house system. The two bathrooms on the left of the image are almost right on top of each other, and the vent runs basically through a shared wall in that area from what I know of it. There are no drain issues in that part of the house.
So would this issue mean, if there is a clog somewhere, it must be after the wye, but I assume before the junction where the bathroom stacks come into play? Bathroom stacks are 3" ABS, the lines coming from the kitchen and laundry room at 1.5". Or is the issue that the horizontal line where the kitchen and laundry room come together should be 2" until it meets the 3"?
The original idea for the laundry room was to add in a standpipe for the washing machine, but code required it to be a 2" which would have meant replacing about 20feet of pipe. Since my mother was just as happy to have it drain into the laundry tub as it always had, it was decided against changing out all the 1.5" pipe.
So my understanding is, I have positive pressure building up between the wye and the trap under the laundry tub. And so the only way to relieve it, is for the trap to bubble until the system balances itself(or the kitchen sink finishes draining).
Could the roof vent be clogged? Would that cause the problem in the lower floor? or could the drain line be partially clogged to the left of the wye, between the wye and the connection to the 3" line? Or am I missing something entirely?
This was a problem years ago, and the solution then was to install a leftover flow-valve from a sump pump behind the washing machine along the horizontal stack. It, worked, but when adding in the AAV that check valve was removed because it was full of soap gunk, and I presumed to think the AAV would solve most of the issues.
Hoping you guys might have suggestions or solutions to this problem. I do not have access to the kitchen vent stack, as it is buried in a wall, behind the kitchen cabinets. I do not foresee my mother agreeing to let me go on an adventure of ripping up her kitchen. She'll likely just accept that it's been like this for years, so let it be. Unless I can run a line to the right of the laundry tub, up that wall and tie it back into the kitchen drain(but I'm not sure if that would solve the problem, as it's just another wet vent, and might just cause the drain to divert itself at whatever fitting I use there?) Or maybe it is a clog, and I'll have to get my hands on a snake(and find or add in, a cleanout in that area. There is a cleanout on the horizontal line from the kitchen, then there is one at the 3" line. I do not think there is one elsewhere that I am aware of at least, not until the connection to the main sewer line at the far end of the crawlspace. If necessary, I could cut in and add one by the wye if the one in the ceiling doesn't work.
Edit2: So after looking at the plumbing coming down from the kitchen, I have noticed the horizontal run has a sag in it. This will be fixed shortly; but could this be causing the issue? It's a 5' run, but end to end difference is less then 1/2" drop, with the middle sag having about an 1" difference. My solution to fixing it is cut the vertical drop coming from the kitchen and shortening it. I'm not sure if this could cause the problem given it's before the wye. But figured the most pieces of the puzzle offered, the better odds of finding a solution.
Attachments
Last edited: