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Coming November 2026
Air admittance valves
AAV Kits
Vent a sink without opening the wall. The kit clamps onto 1½″ tubular drain, lets air in while the sink drains, then closes to keep sewer gas out.
Inline and bottom outlet
1½″ tubular
Up to 8 DFU (branch)
No glue
Gurgling sink? It may need air.
Drains need air to drain. Without a vent, draining water can pull the water out of the trap. That’s what lets sewer gas into the room. An air admittance valve lets air in when the drain needs it and stays closed the rest of the time.
Lets air in
Opens when the sink drains to help keep water in the trap
Keeps gas out
Closes so sewer gas stays in the pipe
Code height
The inline kit sets the valve 4″ above the branch drain
No wall work
Vent under the cabinet. Where your local code allows an AAV, you can vent a sink without running a new vent pipe through the wall or roof.
8 DFU
Rated for up to 8 drainage fixture units on a branch.
Clamps on
Stainless steel bands and a screwdriver or nut driver. No glue or cure time.
1½″ tubular
Both kits connect to 1½″ tubular drain pipe.
Tested
Designed to meet ASSE 1051, NSF/ANSI 24 and EN 12380.
Two kits. Which one fits?
Both do the same job. It comes down to where your drain goes.
AAVKIT-1
Inline AAV Kit
For a trap arm that runs into the wall. The tee goes in the horizontal trap arm and holds the valve 4″ above it.
- 1½″ tubular to 1½″ tubular
- Bathroom, kitchen and bar sinks
AAVKIT-2
90° Bottom Outlet AAV Kit
For a drain that comes up from the floor. The trap arm connects at the side and the drain continues out the bottom.
- 1½″ tubular to 1½″ tubular
- Kitchen islands, vanities and laundry sinks
How an AAV works
A light seal inside the valve moves with the air pressure in the drain.
Water drains
Draining water pulls on the pipe. The seal lifts and air comes in, so the trap keeps its water.
Pressure pushes back
When the pipe pushes air up, the seal closes. Sewer gas stays in the drain.
At rest
With no water moving, the seal sits closed on its own weight.
See it installed
Watch an AAV kit go in under the sink.
Four steps
Inline kit
1
Cut out 1½″
Pick the install location and remove a 1½″ section of drain tubing.
2
Fit the tee
Insert both pipe ends into the tee sockets and push in until they stop.
3
Tighten
Hand tighten all bands with a flathead screwdriver or 5/16″ nut driver.
4
Test
Run the sink and check for leaks.
Bottom outlet kit
1
Cut the tubing
Pick the install location and remove a section of drain tubing.
2
Fit the tee
Insert both pipe ends into the tee sockets and push in until they stop.
3
Tighten
Hand tighten all bands with a flathead screwdriver or 5/16″ nut driver.
4
Test
Run the sink and check for leaks.
Tools: tape measure, flathead screwdriver or 5/16″ nut driver, pipe cutter or hacksaw, deburring tool or sandpaper, and a bucket or towel for the water in the trap.
Install within 15° of vertical, where air can get to the valve and you can reach it later. Check your local plumbing code before you install.
Where it fits
Each kit handles up to 8 DFU on a branch. Typical fixture loads:
| Fixture | Typical DFU |
|---|---|
| Bathroom lavatory | 1 |
| Bar or prep sink | 1 to 2 |
| Kitchen sink | 2 |
| Laundry or utility sink | 2 |
Typical DFU values are based on the International Plumbing Code (IPC) Section 709. Your local code has the final say.
Specifications
| Parts | AAVKIT-1 Inline AAV Kit AAVKIT-2 90° Bottom Outlet AAV Kit |
| Connects | 1½″ tubular to 1½″ tubular |
| Capacity | Up to 8 DFU (branch), where permitted by code |
| Standards | Valve designed to meet ASSE 1051, NSF/ANSI 24 and EN 12380 |
| Gasket | Elastomeric PVC, tested to ASTM D5926 |
| Clamps | 300 series stainless steel worm gear |
| Temperature | -4°F to 140°F |
| Use | Residential drain, waste and vent only |
| Weight | 0.8 lb |
| Packaging | Carded polybag |
Common questions
Is an AAV allowed where I live?
Many plumbing codes allow air admittance valves, but rules vary by state and city. Check with your local plumbing inspector before you install.
Does it replace the vent on my roof?
No. An AAV vents a fixture or branch. Most codes still require at least one vent to open air for the building’s drain system.
Which kit do I need?
If the trap arm goes into the wall, use the AAVKIT-1 Inline kit. If the drain comes up from the floor, like on most kitchen islands, use the AAVKIT-2 Bottom Outlet kit.
Will it fit Schedule 40 pipe?
The kits are made for 1½″ tubular drain pipe, the thin-wall pipe used under sinks. Not sure what you have? Reach out.
Where should the valve sit?
Within 15° of vertical, where air can get in and you can reach it for inspection or replacement. Don’t install it inside a closed wall without an access panel. The inline kit sets the valve 4″ above the branch drain for you.
Will it fix a slow drain?
Only if the problem is missing air. An AAV won’t clear a clog. If the drain is blocked, clear it first.
What temperatures can it handle?
-4°F to 140°F.
Under the sink
Connect to the drain.
Fernco Drain & Trap Connectors join the tubular pipe under the sink to the 1½″ or 2″ drain line in the wall or floor.
- 1¼″ or 1½″ tubular to drain pipe
- No glue or primer
- Made in USA
Documents
The sell sheet, installation instructions, product drawings for both kits and the install video.
Got questions?
Whether it’s which kit, a tricky trap arm or code questions, our team can help. Reach out, or find your Fernco rep.