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Moen Solutions

Single Handle 4" Centerset Lever: Flat Cap Adapter

Moen produces a variety of single handle bathroom faucets. The interior components and assembly are not the same for each model. This article will explain one of the most common handle assemblies referred to as an Adapter. This mechanism was introduced in 1996 and was used on a select group of product through 2009. One of the characteristics of this faucet is the round flat plastic cap. This faucet style utilizes a 1225 cartridge.


flat cap adapter.png


  1. Pull the cap (#1) off of the handle (#4) and lift off the temperature indicator (#2).
  2. Using a 7/64" Hex wrench, unthread the Hex screw (#3) and remove the handle (#4).
  3. Use a Phillips screwdriver to remove the Phillips screw (#5).
  4. Lift the adapter/connector (#6) off the faucet.
  5. Remove the finish ring shield (#7).
  6. Unthread the plastic pivot retainer (#8).
  7. Lift the  finished transition collar (#10) off. 
  8. Lift the washer (#9) off to remove.

For replacing the cartridge see article 1225 Cartridge: Single Handle Bathroom Faucets (Prior to 2009).


  1. Place the washer (#9) on top of the faucet and set the finished transition collar (#10) on top of the washer (#9) with the large portion of the lip to the back of the faucet.
  2. Thread on the plastic pivot retainer (#8).
  3. Replace the finish ring shield (#8) with the open side to the back of the faucet.
  4. Hook the lug on the adapter/connector (#6) into the groove on the pivot retainer (#8). 
    adapter connector install.png
  5. Thread and tighten the Phillips screw (#5) in.
  6. Place the handle (#4) on top of the faucet.
  7. Using a 7/64" Hex wrench, thread the Hex screw (#3) into the handle (#4).
  8. Place the temperature indicator (#2) on top of the handle (#4) with red on the left and blue on the right.
  9. Snap the cap (#1) back into the handle (#4).

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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