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Moen Solutions

How to Reverse Hot and Cold for a 1212 and 1213 Cartridge

This article will give you step by step instructions on how to reverse the hot and cold water flow for an M-Core shower cartridge.

M-Core 3 Series 1213 CartridgeUnfortunately there is not a way to reverse hot and cold for the M-Core 1213 blue cartridge.


M-Core 2 Series 1212 CartridgeUse the following instructions for the M-Core 1212 gray cartridge.



  • 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
  • The following instructions assume the handle and associated handle pieces have been removed. For additional details, visit Single Handle Shower: M-Core and select the type you are repairing. The faucet guide will contain specific information on handle assemblies associated with that style.
  • We recommend covering the drain before beginning so not to lose any parts down the drain.


5 Valve Body


4 Adapter with Check Valves


3 Pressure Balancing Puck


2 Cartridge


1 Cartridge Nut

You will need to pay special attention to the orientation of the Cartridge (2) and the Pressure Balancing Puck (3). This process will require realigning these parts.


The Cartridge (2) will be gray.


Follow Steps 1-5.

Step 1. Using an adjustable wrench, unthread the Cartridge Nut (1) counter-clockwise.

Step 2. Slide the Cartridge (2) out of the Valve Body (5) paying special attention to the location of the posts on the back of the Cartridge (2), either on the top or the bottom. The Cartridge (2) will be blue or gray.

Step 3. Use Needle-Nose Pliers to pull the Pressure Balancing Puck (3) out of the Valve Body (5), rotate the Pressure Balancing Puck (3) 180 degrees and slide it back into the Valve Body (5) until it stops against the Adapter with Check Valves (4).

NOTE: There are two gaskets that need to be compressed between the Pressure Balancing Puck (3) and the Adapter with Check Valves (4). If they come out and/or need to be repositioned, see image below.


Step 4. Rotate the Cartridge (2) 180 degrees aligning the 2 posts on Cartridge (2) to mating feature on Pressure Balancing Puck (3), see examples below. Push the Cartridge (2) into Valve Body (5) until it stops.

Snag_e37290.png Snag_e1672f.png

Step 5. 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.

 For additional information on M-Core Shower products, visit Single Handle Shower: M-Core at

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