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1212 M-Core Cartridge 2 Series: 3 Port Valve

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This article will give step-by-step instructions on how to replace a 1212 cartridge in a single handle M-Core valve shower.

Preparation:

  • The water supply shut off valves must be turned off- see article How To Turn Off The Water Supply To The Faucet.
  • Recommended Tools: Adjustable Wrench or Pliers, Needle-Nose Pliers, 3/32" Hex Wrench
  • We recommend covering the drain before beginning so to not lose any parts down the drain.

 

Handle Removal:

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Using a 3/32" Hex Wrench, loosen the Handle Screw until you can remove the Handle.

 

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Slide the Sleeve off of the assembly.
Parts Legend

 In 2024 the 1212 cartridge was changed, the white Installation Sleeve is no longer required. Parts 3 and 4 that were originally black are now off-white. 

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5 Valve Body

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4 Adapter with Check Valves

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3 Pressure Balancing Puck

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2 Cartridge

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1 Cartridge Nut
Cartridge Removal and Valve Body Preparation

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Unthread and remove the Cartridge Nut (1). Pull the gray Cartridge (2) out.

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Using Needle-Nose pliers, remove the Pressure Balancing Puck (3), O-Ring and Adapter (4).

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Grease the Outer O-ring and inside of Valve Body (5).

Note: If you notice residue inside the Valve Body (5), see article Valve Body Cleaning and Flushing.
3 Port: Shower Only Valve - For 4 Port Tub Shower Valve, Click Here

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Align the tab on the Adapter(4) with the hole in the Valve Body (5).

Note: The Installation Sleeve illustrated above is no longer supplied

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Align the two posts on Cartridge (2) to matching feature on Pressure Balancing Puck (3) and push Cartridge (2) into Valve Body (5) until it stops. Tighten Cartridge Nut (1) onto Valve Body (5) by turning it clockwise until hand tight, and then turn an additional 1/4 turn with a wrench.


 

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To View Complete Installation Video

Click,  M-Core 1212 Cartridge Replacement

 

For additional information on M-Core Shower products, visit Single Handle Shower: M-Core at Solutions.moen.com.

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