Odd plumbing problem

[Tom Wilkinson]

The sink drain at my girlfriend Cindy’s house has started to make gurgling sounds after it has drained. I was assuming one of the p traps might be clogged since it was a recent issue and a 20+ year old house. Both traps were clear but I noticed there is no vent on the drain system. Sink has a window in front of it so cannot have a roof vent. This would make sense as far as the problem but I’m baffled as to why it hasn’t been an issue previously.
Any ideas?
Installing a studor vent this weekend and hopefully that will resolve the issue.
Here is what it looks like currently. Has a cap glued in place where the studor vent should be. Almost looks like on was removed. She said a plumber did change something under there a while back when new disposal was installed but doesn’t know what.
D490A384-0383-423E-9C8D-7CA05DB394B9.jpg

[Breakaway]

Septic tank / cesspool? Is it full?


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[sonofswen]

https://www.build.com/jones-stephens...hId=uu5ZUnu9j9

[Jim Bow]

Is this code:

2B662E10-ED72-4C94-AB82-793DBADAE641.jpg

[Tom from Rubicon]

Looks good to me, but I have a long history of hating insinkerators. That sponge?

Tom

[Ron Williamson]

Since the problem is recent, check nearby drains and stacks.
Our code allows a vent within 5'.
Bathroom sink drains will get disgusting hair clogs that might move downstream.
If you are going to open a clean out, make sure you have a bucket and mop handy.
R

[David W Pratt]

Cleanest undersink I've ever seen.

[Garret]

Cleanest undersink I've ever seen.

I was wondering how many hours of cleaning was done before taking the pic!

A studor vent may well deal with it, but I too have to wonder what changed.

[Tom Wilkinson]

Septic tank / cesspool? Is it full?


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On city sewer system, no septic tank.

[Tom Wilkinson]

I was wondering how many hours of cleaning was done before taking the pic!

A studor vent may well deal with it, but I too have to wonder what changed.

All we did was remove all the stuff in the cabinet. Didn’t clean anything in there yet.

I do wonder what has changed. The sound only comes from kitchen sink. They had a slow/clogged drain in a basement bathroom but that has been cleared. No effect on the sound and all other drains are working well to my knowledge.

[Tom Wilkinson]

Is this code:

2B662E10-ED72-4C94-AB82-793DBADAE641.jpg

I don’t know code well enough to answer that question, but to my mind it is unvented so no. There is no other plumbing anywhere near this sink so it isn’t sharing a vent stack somewhere, and I don’t see how it could anyway since as far as I know the vent would have to exist higher than the P traps.

[sp_clark]

Admitting that I'm no plumber I see a couple of potential issues with the installation as shown, other than there being no direct vent.

First off, behind and underneath the sink's p-trap, that cleanout looks to be offset so the 2" stack has a couple of bends in it? The stack above isn't in-line with the portion going through the cabinet base?

Where that 2" cap's glued to the double sanitary elbow would be an obvious place for a threaded cleanout if needed at all, or where I'd opt to have a studor vent (lacking a proper vent) so I have to wonder what that cleanout's there for?

Second is the convoluted 1-1/2" pipe's path from sink trap to that double wye in the 2" stack. There's always gonna be a lot of waste water in that horizontal section that's slowed down considerably from the number of bends it has to negotiate as it drains away. Any degree of scum build-up in that section will further cause it to drain even more slowly, particularly as there's no vent yet to allow air to enter behind the discharge.

I'm not comfortable with a double 'reducing' sanitary tee in this installation. To my mind there's ample space to have stacked two separate sanitary tees so the disposal's discharge enters the 2" stack above that of the sink's. That would shorten the run of the sink's discharge line & eliminated all of the horizontal bends shown past the p-trap.

[Tom Wilkinson]

I think your first observation is an illusion, the clean out is in line with the stack. I believe the cap was installed later and that there was originally a studor vent installed, but that’s a guess, no direct knowledge other than a plumber did change something under there at one time.
The other bends do seem a bit convoluted but the traps and piping were nice and clean so it appears to work just fine, other than the noise.

[sp_clark]

Illusion, yes. Likely the case. The noise results from movement of air over water as discharge makes it's way out, why venting is necessary somehow.

My own solution to a tricky retrofit:

plmbg.jpg

- caused by a too-high drain inlet in wall (vented, despite window above) as well as other considerations when new countertops were installed soon after we moved in. Vibrations from old, heavy disposal caused sink to come away from countertop, why the wood bit's there now to take the weight. New, smaller disposal helped too with finding a better path for drains in such a confined space.

In your case I think putting a studor vent where that cap is now glued in place is the obvious first step to eliminating the gurgle.

[Breakaway]

Don't those under sink vents emanate waste odors?

Kevin

[Garret]

Don't those under sink vents emanate waste odors?

Kevin

Not until they wear out. Spring loaded so air only goes in, not out.

[hawkeye54]

All we did was remove all the stuff in the cabinet. Didn’t clean anything in there yet.

I do wonder what has changed. The sound only comes from kitchen sink. They had a slow/clogged drain in a basement bathroom but that has been cleared. No effect on the sound and all other drains are working well to my knowledge.

Could it be that the cleared bathroom drain has, in effect ( as there is no under sink vent ) , pulled air over the water in the kitchen P-traps, due to the increased flow rate - causing the gurgle ? ?

[Tom Wilkinson]

Could it be that the cleared bathroom drain has, in effect ( as there is no under sink vent ) , pulled air over the water in the kitchen P-traps, due to the increased flow rate - causing the gurgle ? ?

The gurgle has been happening for a couple weeks, and occurred before and after we cleared the bathroom drain. When the bathroom sink clog was found and fixed thought it would stop the gurgling but it didn’t.

I do know the gurgling goes away if I crack one of the P traps under the kitchen sink allowing air in so the vent should stop it, but that doesn’t explain why it started in the first place.

[Tom Wilkinson]

Don't those under sink vents emanate waste odors?

Kevin

One way check valve. They do need to be replaced once in a while if they fail. Not a perfect solution, but there is no other way to vent the sink.

[Breakaway]

One way check valve. They do need to be replaced once in a while if they fail. Not a perfect solution, but there is no other way to vent the sink.

Noted.

Thank you, and thanks, Garrett.

Kevin

[hawkeye54]

Tom, just an offhand thought - could there be an accumulation of ( eggshells / potato skins / fibrous veggie matter ) partially blocking the trap downstream of the disposer ?



Rick

[Stiletto]

If you remove that cap and replace it with a one way vent the noise will disappear.

[Ron Williamson]

Replacing the cap with a cheater vent will be tricky,since there isn't much air between the cap and the wye.
You don't have any room on the short bit of pipe above the wye for a vent.
Assuming,of course,that the cap is glued.
R

[hawkeye54]

[QUOTE=Jim Bow;6764325]Is this code:

2B662E10-ED72-4C94-AB82-793DBADAE641.jpg[/QUOTE,
'Upon further review' , I kinda side with Jim - Do my old eyes see a power cable in flex conduit , joined by a piece of copper tubing (?) and a rubber hose with hose clamp to another piece of flex conduit ?

[Maybe put that on the to-do list for replacement in the near future ]
If that 'is' a joiner of copper tubing - I would worry about possible current flow from power conductor thru the copper tubing, resting against the metal sink tailpiece, and into the water in the sink - hope I'm just being an 'alarmist'


Rick

[Gordon Bartlett]

One way check valve. They do need to be replaced once in a while if they fail. Not a perfect solution, but there is no other way to vent the sink.

How high is the window above the counter top?
Most kitchen sinks are located below a window, yet they are legally vented.
Typically, the vent runs vertically to a point just above the sink rim but below the lower window framing.
It then jogs left or right until it it clears the window.
From there it turns to vertical again and runs up alongside the window and thru the upper plate into the attic and through the roof.
There are two provisions in most codes that make this scheme code-compliant:
First, horizontal runs in vents are allowable if the horizontal segment is above the flood rim of the highest fixture being vented.
Second, vent runs of 45 degrees or steeper are considered "vertical" for code compliance purposes.
Using those two provisions will usually allow you to find a way to jog around a window.
In your case the studor vent, while a bit half-assed, should work fine, until it doesn't.
Some codes allow them; others don't.
Where they're not allowed, it's probably one of the most violated/disregarded aspects of the code.
Just keep it operating properly and it should work fine.

[RFNK]

I'd just cut the metal pipe from the sink a lot shorter so you get a much steeper run to the outlet. As noted above, that flat run to the outlet would allow too much stuff to settle and also cause water to want to drain back into the p-trap, causing back pressure and gurgling.

Just guessing but I'll bet if you send water through by releasing the sink plug, you'll get more gurgling than if you're just running the tap with the plug out.

[Tom Wilkinson]

[QUOTE=hawkeye54;6764771]

Is this code:

2B662E10-ED72-4C94-AB82-793DBADAE641.jpg[/QUOTE,
'Upon further review' , I kinda side with Jim - Do my old eyes see a power cable in flex conduit , joined by a piece of copper tubing (?) and a rubber hose with hose clamp to another piece of flex conduit ?

[Maybe put that on the to-do list for replacement in the near future ]
If that 'is' a joiner of copper tubing - I would worry about possible current flow from power conductor thru the copper tubing, resting against the metal sink tailpiece, and into the water in the sink - hope I'm just being an 'alarmist'


Rick

The copper tube is the drain hose for the dishwasher. The electrical conduit goes back to the wall but hidden behind the pipe.


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[Tom Wilkinson]

Is this code:

2B662E10-ED72-4C94-AB82-793DBADAE641.jpg

Dishwasher drain. I believe that is normal.


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[RFNK]

[QUOTE=Tom Wilkinson;6764837]

The copper tube is the drain hose for the dishwasher. The electrical conduit goes back to the wall but hidden behind the pipe.


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I see. You could still cut the metal pipe just below the junction with the dishwasher pipe. I just think you need more fall away from the p-trap. I suspect it backs up there and tries to suck air back as water drains back to the p-trap.

[Tom Wilkinson]

All fixed.
Here is a better angle with the studio vent installed, slightly more fall for the right hand sink and a clearer view of the other issues raised.

Still not clear why the gurgling issue began a month or so ago but it’s gone now and drains both drain fast.



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