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Moen Solutions

How to Install an Air Gap


What is an Air Gap?

An Air Gap prevents the backflow of contaminated discharged water into the clean water supply. The use of an Air Gap is required by plumbing codes for certain kitchen fixtures for example a dishwasher or Reverse Osmosis system.

Moen recommends installing an Air Gap in two installation scenarios:

  • A Standard kitchen, Filtration faucet, and a Moen Four-Stage Reverse Osmosis System
  • A Moen 3-in-1 Water Filtration Pulldown faucet with a Moen Four-Stage Reverse Osmosis System

The instructions below will detail how to install Moen's 105895 Air Gap.



  • Required Sink Hole Size: 1 1/2"
  • Deck Thickness: Max 1 1/8"



The Air Gap:
 Parts Legend:
  1. Cap
  2. Escutcheon
  3. Top Mounting Nut
  4. Body
  5. Bottom Mounting Nut
  6. Outlet
  7. Inlet


Installing the Air Gap:
  1. Disassemble the Air Gap: Unthread the cap (1), the escutcheon (2), and the top mounting nut (3). 
  2. From under the sink: Slide the body (4) up through the hole in the deck.
  3. From above the sink: Thread the top mounting nut (3) onto the body (4), leaving about 1/4" (6mm) of the threads above the sink. Under the sink, tighten the bottom mounting nut (5).
  4. Thread the escutcheon (2) and cap (1) over the top of the body (4).
Connecting the Air Gap:

 Parts Legend from Four- Stage Reverse Osmosis System-INS12980:

A- Manifold

B- Sediment Filter

C- Pre-Carbon Filter

D- Reverse Osmosis Filter

E-  Post Carbon Filter



F-Manifold Screws

G- Tank Elbow

H- Cold Water Tee

I-1/4" Black Inlet Tube

J- 1/4" Blue Air Gap Tube


K- 3/8" Blue Air Gap Tube

L- 3/8"  White Tank Tube

M- 3/8" Gray Outlet Tube

N-Sealant Tape

O- Saddle Screws and Nut



P- Foam Seal

Q- Drain Saddle

R- Tank

Installing the Saddle:
  1. Punch out the center hole on the Foam Seal (P) and use it as a template to locate the drilling position above the sink trap. Mark the location with a pencil.
  2. At the pencil mark location, drill a 1/4" (32mm) hole through the wall of the drain pipe.  Note: Do not drill through both sides of the pipe.


  1. Align the holes on the plate of the Drain Saddle and the Foam Seal (P). Remove the film from the Foam Seal (P), and attach it to the inside of the plate of the Drain Saddle.
  2. Aligning with the drip hole, position the Saddle (Q) on the drain tailpiece and securely using the Screws and Nuts (O) provided.
Installing the 3/8" Blue Air Gap Tube (K):
  • The Blue Air Gap Tube (K) may be cut for a taut path to the connector.
  • The tube should not drop below 45° from a vertical position.
  • Be careful to not kink the hose
  1. Slide the 3/8" Blue Air Gap Tube (K) over the Air Gap Outlet (6) and secure with it a hose clamp (sold separately).
  2. Route the other end of the 3/8" Blue Air Gap Tube (K) from the Air Gap Outlet (6) to the connector on the Saddle (Q).
  3. Insert the end of the 3/8" Blue Air Gap Tube (K) into the connector on the Saddle (Q) approximately 1" (25mm) until it stops.
Installing 1/4" Blue Air Gap Tube (J):
  1. Press the elbow retaining ring towards the elbow and pull on the cap to remove the red cap from the elbow of the Reverse Osmosis Filter (D).
  2. Insert the Flow Restrictor and tube assembly included with the Reverse Osmosis Filter (D) into the 1/4" Blue Tube (J) so that the red collar seats against the tube and leaves 1/8" of the thin, clear tubing exposed.
  3. Insert the end of 1/4" Blue Air Gap Tube (J) with Flow Restrictor into the Elbow until it stops (approximately 3/4"). Next slide the other end of 1/4" Blue Tube (J) over the Air Gap Inlet (7) and it secure with a hose clamp (sold separately). Verify that the connections are secure.

Flow Restrictor:



For additional information on Moen products visit and select the type of product you are repairing. The guide will contain repair details, troubleshooting and specific information on assembling handles associated with that style of product.

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