Plumbing, Heating and Pool Repair Guides

STUDOR Vent Buyers Guide


STUDOR is the main distributor STUDOR brand Air Admittance Valves. These products are sold in Puerto Rico, Mexico, Canada and the United States. These products are used instead of the more expensive and complex open pipe venting systems. These vents are used to let the air to get into the plumbing’s drainage waste and venting system.STUDOR Vent Buyers Guide

They will then equalize the pressure as the water drains from the system that will maintain the importance of the water trap. The water trap will prevent the sewer gases from getting into the building. The STUDOR Vent Buyers Guide will show you the most popular venting options from STUDOR. We will show you the Maxi Vent, Mini Vent, Ultra Vent, REDI Vent, CHEM Vent and the TEC VENT. We will show you what each venting system does and what it is used for.


This STUDOR MAXI VENT has a one of a kind design that allows for the proper plumbing ventilation. This vent actually works to protect and prevent the loss of water seals found in traps and eliminate the need for unnecessary roof penetration and vent piping.Some of the benefits of using the MAXI VENT from STUDOR is that they can be used as an individual vents or branch or circuit stack vents. These vents can vent up to 500 DFU’s on a single stack. The MAXI VENT can be easily used on pipe sizes up to 3″ and 4″. They can help decrease the number of fire stop applications. This MAXI VENT can expand its design limits and it has an exclusive vermin protection system, which can save money on extermination services. You can use these vents on both the commercial and residential applications. There is a limited lifetime warranty for all replacements of any defective valves. The STUDOR MAXI VENT meets all of the necessary requirements for the industry standards.


The STUDOR MINI VENTS like the MAXI VENTS can be used an individual vents or as branch vents or circuit or stack vents. This style of vent can be used on 1-1/2 inches and 2 inch piping. This mini vent can vent up to 160 DFU on a branch and 24 DFU’s on a stack. Just like the STUDOR MAXI VENT, these vents can expand their actual design limits making them a bit more accommodating than other brands or styles of venting.

With the STUDOR MINI VENT they will help lower the amount of the number of fire stopping applications needed. There is a one of a kind exclusive rat and rodent protection system. These venting systems are all designed to be used on residential and commercial applications. There is a limited lifetime warranty that is offered to replace all defective valves. These valves meet the ANSI/ASSE 1051 standards as well as the ANSI/ASSE 1050, NSF 14 and the Warnock Hersey standards. These venting systems are 100% safe to use and they are tested before being released to the industry.


The STUDOR ULTRA VENT is used for venting bathrooms including the back-to-back installations. It can be used with applications up to 20 DFU. This venting has a one of a kind patented ball valve sealing assembly for extra protection. Like the MINI and the MAXI VENTS, the ULTRA VENT offers vermin protection as well as expansive design limitations. The STUDOR ULTRA VENT is small in size making it a perfect solution when you need venting in smaller and tighter applications. This venting device will fit pipe sizes 1-1/2 inches and 2 inches. There is a limited lifetime warranty that covers all defective valves. Perfect for commercial and residential applications. This venting system passed the ANSI/ASSE 1051 and the NSF 14 and the Warnock Hersey standards.

When installing the STUDOR ULTRA VENT, you should make sure that it is kept a minimum of about 4″ above the wier of the trap fixture for each single fixture as well as branch venting. You want to also make sure that the valve is installed in an accessible location.


This venting system is designed to be used for the simplicity of drainage and waste venting. This venting design offers to stop the loss of water seals that are located in the traps as well as offer a less expensive way to do an expensive job. The STUDOR REDI -VENT offers single fixtures like island sinks. This system will vent out smaller bathroom groups up to 6 DFU. The REDI-VENT has a one of a kind ball valve sealing assembly.

The REDI-VENT is basically an air admittance valve that can be used for vent termination for individual vents, common vents and circuit vents. This valve was designed to prevent the loss of a fixture trap in these systems. The REDI-VENT is perfect for connection sizes of 1-1/2 inches to 2 inches. When installing these vents they should always be installed with a vertical and upright position after it is roughed in and the DWV system should be pressure tested. This vent has a screen on the inside and the outside of the valve that will protect the sealing assembly from all insects, rodents and debris. There is a limited lifetime warranty for all defective valves and it is compact to fit in the smallest locations. Meets and exceeds the industry standards.


The STUDOR CHEM VENT is designed to help with drainage and waste ventilation that are used for chemical waste systems. This venting system is installed in chemical waste systems when there is a system that is designed by the professional. It should be noted that the STUDOR CHEM VENT should and cannot be installed with applications where any vented fumes are required to be passed through any biological and chemical filters before being released.

This vent can vent up to 6 DFU’s and can expand in design with limitations. The STUDOR Company has manufactured this vent from Flame Retardant Polypropylene that conforms to ASTM D-4101 standards. This is a Schedule 40 dimension of the valve tailpiece that will provide direct mounting on any fusion or MJ fittings. The STUDOR CHEM VENT can be used through available adapters and it can also be used with valves connected to CPVC, glass and Duriron Systems. Due to the nature of the CHEM VENT this venting system can only be used on commercial applications.


The STUDOR TEC VENT is designed for commercial applications for drainage and waste venting. This venting system is classified in accordance with UL2043. This means this venting system can be installed in plenums for a professionally designed system. This system is created with a flame retardant polycarbonate resin. The STUDOR TEC VENT is made from a high tensile strength.

This vent can be used up to 160 DFU’s with an expanding design limitation. The TEC VENT can reduce the amount of fire stopping applications as well as use for residential and commercial use. It is also UV rated for outside installations. The connection sizes of the TEC VENT are 1-1/2 inches to 2 inches. The appropriate temperature of this valve is -40degrees Fahrenheit and 150 degrees Fahrenheit. Installation of this vent should be located a minimum of 4″ above the weir of the fixture for single fixtures and branch venting. These venting systems have a limited lifetime warranty for replacement for any defects in the valves.

There are so many different styles of venting systems out there; But STUDOR Venting Systems are one of kind valves. They meet and exceed all industry standards and they each have their own purpose. Most valves listed here can be used for residential and commercial applications except for the CHEM VENT. The company has been in business since 1970. The company started in Sweden and their products moved into the United States in 1986. The company was a huge contributor to the standards set for the ASSE Performance Standards of 1050 and 1051. Millions of STUDOR VENTS have been installed all over the world. These valves are responsible for saving significantly and also contributing for a cleaner environment.


  1. I recently installed a single bowl sink. At times the sink drains slow. The distance from the sink bottom to the water in the drain line trap is approx 12″ with a total drain line running length of about 20″. I feel that this 12″ (20 total) distance is forming an air trap between the drain line trap and the sink. The Studor Valve lets air into the line, I think I need a valve that will vent the trapped air out of the line. I would install this valve just above the water level in the trap and allow the air above it to be vented when water is dumped into the sink. The valve would also have to have a check valve operation in case the main drain line were to clog and back water up into the sink
    Your thoughts about this is appreciated.

    • Don,
      I would hesitate to install a Studor or other Air Admittance Valve in your situation. Venting usually has nothing to do with how well a drain functions. Instead its function is to protect the water seal of the trap from being siphoned at the end of a vigorous drainage cycle. A toilet is actually a unvented drain. First the drain doesn’t flow well but then it picks up speed as the weight of the water falling pulls the water out, then it gulps air at the finish. That is how an unvented drain acts.

      I would suggest looking at other causes.

      Lack of a vent can become apparent when there is a clog in the line as the pipe is filling with water and the air has no place to go but a Studor or AAV will not help there because it only lets air in and not out. Cleaning the line would help.

      If you have a grid strainer and a sink without an overflow air can be caught between the grid strainer and the water in the p-trap slowing things down. This is just the nature of the beast when it comes to grid strainers installed on sinks with no overflow. Sometimes drilling out the holes in the grid slightly larger can help. Getting rid of the grid strainer and going with a lift and turn drain can help too.

      The same thing can happen with a pop up drain on a sink without an overflow. Sometimes raising the pop up as high as it can open will help. If you have a pop up you can remove it and see how it drains with the pop up stopper to see it it is the problem.

      If these don’t help I would suggest taking a digital picture of the drain pipes under the sink and sending them to Wethead Media by using the “contact us” button and they will share the picture with me. You may have done something wrong with the drain pipes that is causing the slow drainage. Not to worry we’ll help you get things working right…

      Let us know how you make out with this. It is not a venting problem, there are probably 25% of the drains in the US not vented and they drain fine.

  2. Hi
    I am trying to connect my Dishwasher/Disposal unit after getting a new sink. The new sink is deeper so the Mini vent does not fit.Can I use a adjustable pipe( the one with extendable size) and install the vent a little lower ? Does it have to be upright?

    • If you are talking about the dishwasher airgap it needs to be mounted up right and through the countertop.
      Think of this being like a miniature sink and faucet that doesn’t allow dirty water from the drain to back up into the faucet which is fed by water coming out of your dishwasher. Instead the miniature sink overflows and the watercannot reach the level of the faucet and backflow into it.

      The drain line from this dishwasher airgap or, miniature sink should be pitched straight down to the disposer or dishwasher tailpiece connection without any downward loops that would hold water and no kinks or you will have water spilling out of the airgap often.

    • Hi Dave,
      Sorry I didn’t see this sooner but the solution is well outlined in the reply I just made to John Makula.

      Please take a look at that and I hope it helps…

      When it comes to grid drains on vessel sinks I say, “Some of the worst ideas in plumbing survive by being fashionable.”

  3. I have a same situation as does Dave above with two vessel sinks that also drain slow. I just happened to run into a plumber who told me this was a common complaint and that a possible fix was to insert an inline studor vent. We have tried it with great success yesterday but just went online to check the studor website for any feedback. It seems the manufacturer suggests its use yet Redwood on Sept 15th says it’s not necessary. I just want to confirm it will not suck the water out of the trap. Thanks John.

    • Hi John.
      I think what Redwood was saying was that if there is already a vent protecting the trap seal the studor vent is an unnecessary ad on. If you currently have an s-trap or unvented situation it would be a good addition but it probably will not solve your slow draining vessel sink.

      The problem with vessel sinks is they use a grid drain with relatively small holes. The small holes cover with water trapping air between the grid and the water in the trap. Vessel sinks not having an overflow do not let this air escape so they drain slow.

      My solution as far as the grid drain is to carefully take a drill and make the grid holes as large as they can be without tearing up the grid. This is a delicate operation but will give you significant improvement in the drainage. lowering the amount of entrapped air blocking the flow. The problem is the air is on the wrong side of the trap for venting to help.

      Another solution which is IMHO the best solution is to ditch the grid drain and install a lift and turn drain they are far superior to the grid in allowing the air to escape and drain quite well.

  4. Hello,
    I’m in the process of moving my kitchen to a greatroom. Within it, I will have an island which will include a single bowl sink, disposal, and a dish washer. Incorporating a traditional vent system will be difficult. Will an AAV be reliable in this application if installed correctly? Is an air gap necessary for the disposal? The arrangement in the existing kitchen is as follows: the sink is trapped via the disposal. The dish washer has its own trap under the floor in the basement; it is then tied into a tee where both it and the sink/disposal can clow into the main. It has worked well for my 41 years in the house.

    Tom Raiber

  5. Do Studor vents need to be replaced ? I havee one under my bathroom sink, and for the last week I have been smelling septic gases. I have removed the drain and cleaned it, and have also used acid to remove any clogs that may have been stopping up the line. The smell is still present. Should I replace the vent ?

  6. Hello –

    I live in Mexico and have a couple of problems with smell that comes back up the drain pipes. In particular we have a tub that was connected to the shower drain below the trap so that sewer smells come up the drain and into the tub drain pipe and spill way. Can I use this product if I cut the tub drain pipe which is above the floor ( this is an antique claw foot type tub) and insert the vent?

    Also, saw your note above regarding toilet drain. Don’t toilets need to be vented? We also have 1 that dosen’t seem to flush properly or fast enough and I assumed its because its not vented.


    • Hi Nick,

      The flow of sewer gases into your home should be stopped by a trap installed on each fixture. The water in the trap acts as a seal stopping the sewer gases from entering the home.

      Venting protects the trap seal by preventing the water in the trap from siphoning and from blowing out of the drain from unequal pressures in the drain system.

      These valves provide a one way flow of water into the drain affording protection to the trap seal. It does not allow air to flow out of the drain. In some systems and designs this may be a problem. The best possible vent is a vent through the roof.

      So the direct answer to your question is that no it probably will do nothing to help you out. You need a trap installed on the tub line.


  7. We have noticed some water in the cabinet under the sink. We are not sure where is is coming from however I wiped everything down and noticed that there was water on the top of the studor. Is it possible that the valve is defective (the valve is about 2 years old)and leaking as I have let the water run continuously for 10 minutes and do not see any of the other fittings leaking? Could it have something to do with the dishwasher draining? Please let me know your thoughts. Thank you!

  8. Have just installed two vessel sinks with no overflows and grid strainers, changing their positions by four feet from the original single vented sink. They drain fine, no backup of water in the bowls; however, both sinks make a gurgling noise after all water has cleared its bowl? Would an air admittance vent eliminate the annoying noise?


  9. I want to install an inserted Medicine Cabinet over a sink. My contractor is saying that he may have to put an elbow in the sink vent pipe which he is assuming runs up to wall behind the sink. This will also require the cutting of joists in a support wall. Any thoughts on this?

  10. I have a double sink vanity, where each sink has its own trap. The drain line runs into the wall on the right; the shower is on the other side of that wall. I get a sewer gas odor from the left sink, and sometimes from the shower during the first minute or so of shower use. Would adding an AAV just after the left sink help?

  11. I live in a very windy area, when the winds reach over 70 mph the water in my traps is getting sucked out due to the up and down movement of the water trapped in the traps.
    Will a studor maxi vent work on my main stack to prevent this?

  12. Hey! I have the same issue as Don, water under the sink, except ours is 5 yrs old. I didn’t know if maybe the drain was clogged or how the
    redi-vent works, is there something I need to adjust?……any suggestions appreciated……Thanks!

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