Best Diaphragm Valves in 2020

Studor 20341 Mini-Vent with PVC Adapter 1 1/2-Inch or 2-Inch Connection Review:

Worked as expected. The old one was original to the house and was for the washing machine drain line. The drain kept backing up. I snaked the drain but could not get it in far enough. Tried a plumbing bladder & a jet nozzle to no avail. Tried Draino Gel over night. Still backed up when using the washing machine. Finally gave up and called the plumber. He removed the old Studor Vent and the washer drained without a problem. He suggesting getting it on Amazon rather than paying him $200.00 (yes you read that right) for a new one. He suggest replacing these every 5 years along with the washing machine hoses & drain hose. Highly recommend this item.

1-1/2 inch Tuuber Vent 2x Superior Seal Air Admittance Valve Review:

I like the fact that I could either put the vent under the sink, or I could take the vent pipe up the wall to the attic--New Construction. Either way, I do not have to crawl up on the roof and cut a hole in the roof and buy flashing and install that too, and the price I paid was much lower than buying local; I love saving money--Save a dollar, and it is like earning $1.50 considering the taxes. Too, since the construction site is outside any city limits, no city taxes to be paid, and buying from Amazon with the Amazon store card, there is 3% put into my account.

Studor 20349 REDI-Vent Air Admittance Valve, 1-1/2" or 2" ABS Adapter, White Review:

I had a fowl odor emanating from a cabinet under the sink in my motor home bathroom. All of the information I found online dealt with treating the tank with grey water treatments. Others suggested it may be a blocked vent. I removed the pee trap to check for stinky stuff that may be lurking. While removing the pee trap, I noticed a vent hidden behind the sink. What is this? I unscrewed the 1.5 inch doohicky and found it once upon a time had a one way valve. That valve was shot out. So, down the rabbit hole I go. This could be your answer or not. I wouldn't want to ruin your rabbit hole fun . So trip on my friend.

Studor 20391 AAV Tee for Redi-Vent Review:

I want to provide some clarification. The posting is somewhat misleading because it states "Tee for Vent", instead of "Tee WITH Vent" which is what it should state since both pieces are includes. Due to the posting and some of the customer reviews I read, I thought the vent was sold separately and ended up buying a duplicate vent separately for $13, but it was already included in this package. I was able to resolve by calling Amazon and getting a refund for the extra unused piece which I asked to return, and also was granted a $5 credit because the rubber gasket was missing from the box (I had to make a trip to the hardware stop and buy separately since I needed to install vent immediately).

I must say, after seeing Youtube videos of this baby in action and testing it for myself, IT WORKS WONDERFULLY! The velocity of the waterflow increased substantially! I used my cell phone to film the water flow (faucet open at it's max) before and after installation to my 1.5 inch pipes, and the time it took to drain was virtually cut by about 70 - 75%. At maximum water pressure, after 30 seconds of running the water, the water still kind of accumulates but no more than 1/2 inch and once shut off it now takes about 5 seconds to drain which is so much quicker than what it was taking before (30-35 seconds). For this price, both pieces are a bargain, I'm so happy with it and HIGHLY RECOMMEND for everyone experiencing delays with draining, especially anyone with a basin sink!

Studor 20395 Trap-Vent, Integrated Trap and Air Admittance Valve, 1-1/4" Outlet, White Review:

I'm not sure this meets code in most places. Just about every code I've read says the aav should be mounted 4" above the top of the outlet, and some say 6" above fixture flood. I'm no plumber, nor plumbing inspector, just a heads up if you live in an area that it will have to pass. That said whoever remodeled my bath before selling the house to me probably removed a sink that had an overflow which works kind of like a vent allowing some air to be pulled down the drain. This is in an older house and there's no vent for this sink. Worse yet there's an in wall medicine cabinet above the vanity taking up the wall studs above the drain. Could I work around those problems, yes, but it would be A LOT of work. There's not even room for the T shape AAV valves that mount inline. There's so little room I ended up cutting 3" off the tail end of this as the end hit the back of the 90 inside of the wall. Anyhow the sink drains 3 to 6 times faster than it has been.

Studor 20396 Trap-Vent, Integrated Trap and Air Admittance Valve, 1-1/2" Outlet, White Review:

We recently remodeled our apartment, and replaced the old on-counter glass sinks with ceramic vessel sinks in our two bathrooms.
When we did the test run after installation, none of the three new sinks would drain properly. Bummer! The sinks would fill up to about 75%, then you would hear a sucking noise, and all the water would drain in an instant. Weird!
My handymen couldn’t figure out why nor could the plumber who believed the problem was a clogged sewage pipe in the wall. In two bathrooms all of the sudden? I didn’t believe it, and decided to do some research online.

Why did the old lavatories drain with no problem at all while the new ones didn’t? There had to be a reason other than a clog. Could it be a venting issue? The old sinks had a pop-up drain while the new ones came with a grid drain. To prove we were looking at a ventilation problem rather than clogged lines, I stuck a straw in one of the drain holes and turned the water on. Bingo!! Sinks drained just fine!
So I bought three Studor RediVents and had them installed. While the sink in the guest bathroom works great with this type of AAV vent the two sinks in the master bathroom still had the same draining issues.

When I compared the plumbing underneath the sinks in the two bathrooms I noticed a difference in the set-up. The tailpiece (part of drain that goes down to the p-trap) of the drain in the guest bathroom could be fed directly into the p-trap.
In the master bathroom, however, we had to add another piece of pipe to the tailpiece, extending it by approx. 3”, to connect it to the p-trap. My guess, with water rushing down the drain, air got trapped inside the long tailpiece with nowhere to go. To get to the RediVent the air would have to be pushed down the extended tailpiece and through the p-trap first – a long way.

I eventually came across the Studor Trap-Vents, and ordered two of them as a last resort after three weeks of total frustration. The vents did the trick! Air can now escape easily right at the p-trap, and the sinks drain perfectly. Best thing of all, the plumber was so embarrassed he never charged me for the visit.