Need AAV help, please

[Shari]

I have a slow draining bathtub and I believe the problem is inadequate venting. The bathroom is located in an area that is similar to a basement. It’s a hillside house and the back wall and part of the sides of the first floor are concrete. When the plumber did the work, many years ago, AAVs were not allowed in my area. He told me the the vent line was too long and the bathtub would drain slowly. We went ahead because our options were limited. It does drain, but slowly as promised. Everything else on the same vent works great: toilet, sink, washing machine. The drain lines are under a concrete slab.

I am posting a photo of the work being done and a drawing with measurements.

I have three questions.
1). Will an AAV make the tub drain faster?
2). If I use one, where should I have it placed?
3) If it has to stick out of the wall, can I cover it with some decorative cover?

 

[Reach4]

I have a slow draining bathtub and I believe the problem is inadequate venting

The problem with your slow-draining tub is not venting. Adding an AAV will not help with that.

Did the tub ever drain well? If so, you have a clog. Have you pulled the stopper and the drain lever out?

I am not a pro.

 

[Sponsor]

 

[WorthFlorida]

Is there another tub in the home to compare the draining? Bathtubs generally drain slow anyway. Is it any worse when first installed? If it is right at the stopper it fills with hair quite readily. If you know how it is very easy to remove the stopper. There are YOUTUBE videos on how to do it.

https://terrylove.com/forums/index.php?threads/how-far-can-a-vent-run-horizontal.8007/
https://codes.iccsafe.org/public/document/code/550/9795976

 

[Shari]

It has always been slow. The plumber said it would be due to the vent line being too long.

Wouldn’t an AAV put air into the line and help with the too long vent line problem?

 

[Shari]

I read the link to the other question. My ratio of horizontal to vertical is the opposite of what it should be. 2/3 horizontal and 1/3 vertical. I believe the vent is 1.5

 

[Shari]

I missed a few feet. vertical is 16 horizontal is 18. So almost 50-50. Pipe is 1.5

 

[hj]

It has NOTHING to do with the vent. The length of a vent is a theoretical dimension and has little relationship to the real world. In fact, a missing or improper vent will sometimes create BETTER drainage than a proper one. You have some other problem but we would have to see how it was actually installed to try to answer your question. Your drawing does NOT show anything that could case poor drainage. The fact that the "plumber" used a combo for the washer indicates that he was not a very good plumber. He didn't install two traps on the tub, did he? That would be one reason for poor drainage.

 

[Shari]

I love Cave Creek. Well, I can’t look, but i’m pretty confident there aren’t two traps. Thanks to everyone for their help.

 

[WorthFlorida]

The layout and venting all looks proper.

A closer look at the picture, the 1-1/2" tub vent changes to a 2" vent just before the sink so you have plenty of venting. Tub drains are 1.5" but everything else is 2". The bathroom trap is 1 1/4" but it drains into a 2" pipe. Since the toilet is next to the tub and that must be a 3" drain, it looks like only a foot or two the tub drain changes to a 3" pipe. There is no picture of it but since this was done by a plumber and everything else drains fine, you may have a different thought in how fast a tub should drain. Generally, when the shower is in use the water should drain and not back up as long as your shower head has not been modified to dump all the water it can deliver. By law a max flow rate of a shower head is 2.5 gpm but most now will be in the 2 gpm range since certain parts of the country requires 2.0 or 1.8 gpm max. If it the drain backs up during a shower, almost certain there is blockage.

If you remove the tub stopper, if there is one for the drain, or the stopper from the overflow, check for hair accumulation and clean.With a towel or something else cover the drain and add a few inches water. Then remove the towel and let it drain. You may notice it will drain a little faster without the stopper in place. It's only a 1.5" pipe and right at the tub drain it is a short 90 degree turn that slows down the flow. You don't want the tub to drain too fast as it can overwhelm the waste line should a toilet be flushed or the washing machine discharges water at the same time. An old top loader washing machine may pump out 15 gallons in two minutes, a bathtub filled would be 25-40 gallons of water.

 

[Shari]

Thanks. I’ll give this a try tomorrow.

 

[Mliu]

since this was done by a plumber

Just because the OP referred to the installer as a "plumber" doesn't mean he was actually a licensed plumber. Laymen will often refer to anyone who installs pipe as "a plumber" even if that person is just a handyman. As HJ pointed out, this "plumber" incorrectly installed a combination wye on the trap arm for the washer drain instead of a required sanitary tee. So we really can't assume that any of the other drains were piped correctly.

IMO, the OP should hire a LICENSED plumber so scope all the drains that were installed by this "plumber" to find out what's really going on under the concrete. He says its always been show (plus his "plumber" warned him it would be slow, a bad omen) so I think he has a much bigger problem than some hair in the tub's stopper.

 

[Shari]

I do know the difference between a plumber and a handyman. He was a licensed plumber. I would not hire a handyman do put in new plumbing lines.

 

[Mliu]

I do know the difference between a plumber and a handyman. He was a licensed plumber. I would not hire a handyman do put in new plumbing lines.

Then, as HJ said, he was not a very good plumber. He installed a combination wye (instead of a sanitary tee) on the trap arm for the washer drain.

This shows why the combo why is prohibited.

This connection should be well-known to any competent plumber. Since he made this "rookie" mistake, you should wonder what other mistakes he made in your plumbing. Additionally, he told you your bathtub would drain slowly and blamed it in advance on the venting. If the drainage pipes and venting were installed correctly to code, there would be no need for such a disclaimer and your tub would not have drained slowly from the beginning.

Find a better plumber and have your pipes under the slab scoped. You may be (unpleasantly) surprised, but at least you might get your plumbing fixed correctly. Too bad you waited so many years to address this as you probably could have held your original plumber responsible for the repair costs, which may be considerable if you have to cut open your slab.

 

[OLD TIMER]

If its a lift bucket type stopper the linkage may need adjusting.

 

[Terry]

Your "plumber" should have used a legal santee at the vent, and not an illegal combo fitting.
This picture shows a santee installed the correct way.

The plumbing in your picture needed at least a 2" vent.