Is this bad?! Yes, it needs fixing.

[Jesse Okiror]

Plumber installed an island loop with this setup. He says it was done this way because connecting the vent back to the drain would cause more damage to the slab (this is a reno and we had to cut about a foot deep into the slab to make this happen). What problems am I looking at down the road?

 

[Tuttles Revenge]

Yes. Yes it is. Its a totally flawed design. Condensation happens in any plumbing system, especially where there is hot water involved such as kitchen sinks and dishwashers. Vents are supposed to be designed with the ability for the condesation build up inside or flood/backup events to drain back into the drain portion of the system.

 

[Sponsor]

 

[Tuttles Revenge]

without opening the slab, there isn't any good way to fix that short of cutting the "vent", vacuuming out all the water and capping it off. Then install an air admittance valve 4" above the trap arm.

even if you connected the "vent" to the drain above the floor level to have some place for air to flow and the water to drain out, there will still be fetid water that will never move or clear out.. getting sludgier and sludgier over time.

 

[Terry]

An Island Vent looks like the one below, where the loop has a natural drain so that it's always dry.
I agree that the easy fix is to cut out the loop and use an AAV.

 

[wwhitney]

Dallas uses the UPC, I think, so an AAV may not be an option. In which case the only option is to break open the slab to fix the plumber's error.

FWIW, I don't believe the fitting arrangement has to be exactly as shown in the example. The important part is that the low point of the vent be hooked into the drain. So in reference to your drawing, that quarter bend at the vent low point should be a san-tee, and the bottom of the san-tee should connect to the drain with a wye or combo.

Cheers, Wayne

 

[Jesse Okiror]

Okay, two things:

1) the plumber said he’d install an “inline studor vent” to make sure there’s plenty of venting. Said nothing about caping the current vent. So two ways to vent.

2) this current setup passed inspection. In my mind that means the work was good. Am I thinking about inspections wrong? I put a lot of faith in inspectors checking the work of my tradespeople

An Island Vent looks like the one below, where the loop has a natural drain so that it's always dry.
I agree that the easy fix is to cut out the loop and use an AAV.

 

[wwhitney]

2) this current setup passed inspection. In my mind that means the work was good. Am I thinking about inspections wrong?

Yes, a passed inspection just means the inspector failed to note any deficiencies. This loop vent misconfiguration is an obvious deficiency that the inspector missed. Different inspectors will be more or less thorough for various inspections.

As to the AAV solution, I would not accept that unless AAVs are approved for use by the plumbing code applicable to your project. Since the original scope of work would have been much simpler without a loop vent, I suspect they may not be.

Cheers, Wayne

 

[Terry]

Okay, two things:

1) the plumber said he’d install an “inline studor vent” to make sure there’s plenty of venting. Said nothing about caping the current vent. So two ways to vent.

2) this current setup passed inspection. In my mind that means the work was good. Am I thinking about inspections wrong? I put a lot of faith in inspectors checking the work of my tradespeople

Plenty of times inspectors miss things. And in some cases they may have never plumbed themselves.
I've had jobs where six weeks worth of work was never looked at.
I've almost never had an inspector go in a crawlspace to check. Sometimes when they know you, they say hand me the permit to sign. And off they go.
Sure,
I used to work with Tuttle's dad in the 70's. I was plumbing five homes a week with my three man crew. One of 150 plumbers.
I'm pretty damned sure that Tuttle and I know what plumbing should look like.
Can you show me any code that explains how your plumbing was done right?

 

[Reach4]

Using an AAV would have been an easy way.

AFAIK Dallas is under IPC. https://dallascityhall.com/departme...nts/pdf/BI_2015_IPC_Amendments_01-25-2017.pdf says IPC 2018 with amendments that don't seem to reject AAVs.

 

[Jesse Okiror]

I’m actually in Desoto, TX. I know that AAV doesn’t pass code here because that was our first plan and the inspector rejected it lol. But then he passed this other setup for the island loop.

Appreciate what I’m learning today about inspections.

It is what it is at this point. Gonna put the AAV on there.

Plenty of times inspectors miss things. And in some cases they may have never plumbed themselves.
I've had jobs where six weeks worth of work was never looked at.
I've almost never had an inspector go in a crawlspace to check. Sometimes when they know you, they say hand me the permit to sign. And off they go.
Sure,
I used to work with Tuttle's dad in the 70's. I was plumbing five homes a week with my three man crew. One of 150 plumbers.
I'm pretty damned sure that Tuttle and I know what plumbing should look like.
Can you show me any code that explains how your plumbing was done right?

 

[Jeff H Young]

Wow Sorry to see the poor work Jessie. Well I dont know if your code allows an AAV and dont base it by what the inspector either knows or says he knows. But the plumber aint too bright .
At this point floor patched Im assuming Id run with an AAV even though I hate AAV legal or not . Easy fix yes. but annoying I wouldnt want that in my house and payed some moron to put a island vent . Im a minority in that I dont use them (aav)
your inspector and plumber both kind of missed it. but its likely a combo inspector probebly knows nothing about plumbing.
I could take a few classes and go out and inspect every trade but and sure I could sighn a job card try my darnest to see good work but think Id be a bit challenged outside of plumbing.

 

[Tuttles Revenge]

I would love to hear anyone defend that original installed design... I'm not the smartest plumber out there but I know 100% that could never work as a vent.. if its allowed its because someone was drunk, stupid or got paid off.

 

[Tuttles Revenge]

I wonder if this is a good solution to maintain a loop vent that allows the condensation to drain into the drain? Cap off the vent and connect the vent under the trap arm and cleanout. Its not as good as taking off from the invert of the pipe where its free air , but its at least got air movement and vastly superior to the original installation.

 

[Jeff H Young]

I wonder if this is a good solution to maintain a loop vent that allows the condensation to drain into the drain? Cap off the vent and connect the vent under the trap arm and cleanout. Its not as good as taking off from the invert of the pipe where its free air , but its at least got air movement and vastly superior to the original installation.

View attachment 75682

Tuttles I think if the vent (thru roof) was tied back into the drain perhaps , because rainwater going to collect. and it still wouldn't comply , so if an AAV was also added along with that it might be better . I wouldn't want to cap the vent

 

[Michael Young]

An Island Vent looks like the one below, where the loop has a natural drain so that it's always dry.
I agree that the easy fix is to cut out the loop and use an AAV.

I disagree with Terry.
The EASIEST fix is to leave the loop right where it is. Just pop an AAV onto the stubout under the sink anywhere downstream of the trap assembly.