Upside-down Air Admittance Valve

**JB Thompson** · 03-07-2011, 08:07 PM

I found a set of installation instructions on line for the Studor brand of AAV's.

It says to install "in the vertical upright position".

I don't know what brand this particular unit is; however, my question is: does anyone know of a brand(s) that can be installed upside-down?

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**Scott Patterson** · 03-07-2011, 08:14 PM

Originally Posted by JB Thompson

I found a set of installation instructions on line for the Studor brand of AAV's.

It says to install "in the vertical upright position".

I don't know what brand this particular unit is; however, my question is: does anyone know of a brand(s) that can be installed upside-down?

For starters that is a mechanical vent and not an AAV. Regardless it must be installed upright for it to work properly.

Next, mechanical vents are not approved for residential use. The can be used in manufactured homes and trailers. When they fail they do so in the open position and allow sewer gas into the home. AAV's fail in the closed position locking out sewer gas.

**JB Thompson** · 03-07-2011, 08:22 PM

Originally Posted by Scott Patterson

For starters that is a mechanical vent and not an AAV. Regardless it must be installed upright for it to work properly.

Next, mechanical vents are not approved for residential use. The can be used in manufactured homes and trailers. When they fail they do so in the open position and allow sewer gas into the home. AAV's fail in the closed position locking out sewer gas.

Well I feel stupid...nothing new; I'm used to it.

I never understood there was a difference. Heck, I thought mechanical vents were the same thing.

Is an "auto-vent" a mechanical vent?

**JB Thompson** · 03-07-2011, 08:25 PM

Originally Posted by JB Thompson

Well I feel stupid...nothing new; I'm used to it.

I never understood there was a difference. Heck, I thought mechanical vents were the same thing.

Is an "auto-vent" a mechanical vent?

I typed "plumbing mechanical vent images" into google and found this.

What is that thing under my sink?

Good job, Scott!

**JB Thompson** · 03-07-2011, 08:31 PM

Scott,

This device from Watts is black and says "air admittance valve". Is this just a mislabeling or do some AAV's look like MAV's?

280PV ProVent Air Admittance Valve, Air Admittance Valve, Brass & Tubular - Watts

Thx

**Scott Patterson** · 03-07-2011, 08:51 PM

Originally Posted by JB Thompson

Scott,

This device from Watts is black and says "air admittance valve". Is this just a mislabeling or do some AAV's look like MAV's?

280PV ProVent Air Admittance Valve, Air Admittance Valve, Brass & Tubular - Watts

Thx

I have never seen the ABS (black) AAV in use, only in photos. They also make a Red color, but I have never seen it either. I'm not sure if the Watts AAV in the link is even in production as they do not offer any additional information on it.

I still call out all black vents as a mechanical vents, One sure way to tell is if you can see a spring in the vent. If you see a spring it is a mechanical vent. With an AAV you can take it off and you can hear what sounds like a ball rolling or rattling around inside of it.

**JB Thompson** · 03-07-2011, 08:59 PM

I appreciate your help.

**Jerry Peck** · 03-08-2011, 05:41 PM

Originally Posted by JB Thompson

I found a set of installation instructions on line for the Studor brand of AAV's.

It says to install "in the vertical upright position".

None can be installed upside down.

They need to be installed vertically, or within 15 degrees of vertically ... oh ... and "vertically" means "up" ...

... otherwise it would be installed "inverted".

**Garry Sorrells** · 03-09-2011, 06:52 AM

Here is something to ponder.
2006 International Plumbing Code (IPC)

Section 917 - Air Admittance Valves

917.1 General

Vent systems utilizing air admittance valves shall comply with this section. Individual-and-branch-type air admittance valves shall conform to ASSE 1051.

Now;
Home Depot sells the Oatey 1-1/2 in. ABS PTC In-Line Cheater Vent @ $6 Model # 39012
Which does not meet ASSE 1051 which is requires to meet the Inter. Plumb. Code.

It also sells the Oatey SURE VENT® AIR ADMITTANCE VALVE@ $20.
Which does meet ASSE 1051 which is requires to meet the Inter. Plumb. Code.

The only application that I am aware for the mechanical valve is for Travel Trailers.

So why does Home Depot sell something that when used violates Plumbing Code. If the application is so narrow for the non compliant valve, why put the unknowing consumer in a position of installing something that will violate the law?

For further amusement I called a local HD and asked if they had these two valves in stock, which they did. I further asked if they both met the Pluming Code . Which HD said they did. I specifically asked if the Oatey 1-1/2 in. ABS PTC In-Line Cheater Vent met the code requirements and was told it did.

Stopped into a different HD that same day and asked a sales person on the plumbing floor about the valves and he knew where they were and that they sold allot of the $6 vents. I asked if knew that it did not meet code, which he did not. Told him that it did not meet code and the limited acceptable use was for RV Trailers, which he thought was interesting. Then asked why HD was putting their customers at risk by selling something that only violates plumbing code and promoted an incorrect installation by HD's complicity with the installation. No real answer, but thought it was interesting question.

Many plumbing items can be used in many application, right and wrong. But when an item has only one real function it is interesting that a store would not take the higher ground and represent the best interests of the customer. But rather go for the few dollars on a cheep item and say screw the customer, if they buy it its their uninformed fault.

Vertical , horizontal or upside down. If you were not supposed to use it in the first place what's the diff. Only to say that the item that was used in a wrong application was also installed wrong (a twofur). Though they would know what should be done to correct installation.

**Corn Walker** · 03-10-2011, 07:37 AM

Originally Posted by Garry Sorrells

The only application that I am aware for the mechanical valve is for Travel Trailers.

So why does Home Depot sell something that when used violates Plumbing Code. If the application is so narrow for the non compliant valve, why put the unknowing consumer in a position of installing something that will violate the law?

I don't know, but I'm glad they do. For a science project, my son and I built a model submarine (maybe we should christen it the USS Jerry Peck) using plumbing supplies, including the cheap, non-code compliant valves for the ballast tanks. I'm happier to have spent $12 instead of $40 on the valves.

How's that for another application?

**Garry Sorrells** · 03-10-2011, 09:34 AM

Originally Posted by Corn Walker

I don't know, but I'm glad they do. For a science project, my son and I built a model submarine (maybe we should christen it the USS Jerry Peck) using plumbing supplies, including the cheap, non-code compliant valves for the ballast tanks. I'm happier to have spent $12 instead of $40 on the valves.

How's that for another application?

Aaaaaaaaaaaaaaaah. But, how much more could have been learned if you had designed, engineered and fabricated your own valves for the sub.