How to Change the Cartridge of a Delta Monitor Shower Valve.




The purpose of this Instructable is to illustrate how to change the cartridge of a Delta Monitor shower valve.  The cartridge is the internal working part of the shower valve, if the cartridge is bad, water will continually leak out the spout or you will notice a sudden loss of pressure.   Expensive repair bills may be avoided when you make the repair yourself, also your water bill will decrease, both will save you money. This task can be performed with common household tools.  If you do not own any of the following tools listed, they can be purchased at a local hardware store.  The hardware store should also carry the replacement cartridge for the Monitor shower valve.  To ensure the shower valve is in fact a Delta Monitor, look on the trim plate, there should be the words Delta on the bottom and Monitor on the top (see pictures).  Although these instructions are written so anyone can complete this task, an avid do-it-yourselfer should be able to finish in about 15 minutes.

Step 1: Gather Material Needed

To easily execute this process the following tools are necessary:

     • Allen Wrenches
     • Tongue and Groove Pliers
     • Needle Nose Pliers
     • Faucet Grease
     • New Cartridge

Step 2: Turn Off the Water and Drain the System.

Caution: Treat old valves with care.

1.  Locate the main water shut off for the house or apartment.  It will most likely be located in the basement of a house or duplex.  There will be one of two types of valves ,a ball valve (see picture 1) or another style of valve shown in picture 2. 

2.  Close the ball valve off by gripping the handle and rotate it clockwise.  Move the handle until it has moved a full 90° from the original position. For the other style of valve pictured, grip the round handle and turn it in a clockwise direction until is fully closed.

3. Check to see if the water is shut off by turning on a nearby faucet, the water should slow down and stop running after 30

Tip: If the water does not shut off completely, return to the main shut off, open it back up by turing it in a counter-clockwise direction and the shut it again, this time applying slightly more pressure.  If the water still does not shut off, call a professional to replace the valve.

 4. If the water stops completely, leave the faucet open. This will drain the water that is left in the pipes once the shower cartridge is removed.

Step 3: Remove Trim From the Valve

1.  Locate the set screw on the handle.  This will be in a recess somewhere on the handle.  To disassemble the style in picture 1, the lever will need to be removed to access the screw.

2.  Once the lever is removed the screw can be found (see picture 2). Try to evaluate what size allen wrench is going to be needed.  Insert that wrench into the hole.  To make sure the allen wrench is seated into the set screw, wiggle the wrench back and forth.  If the wrench does not move at all you have selected the appropriate size wrench; if the wrench moves without resistance select a different size.  Select the wrench that moves the least.  For the other style of trim, the set screw can be found in the recess under the lever (see picture 4).

3.  Loosen the set screw and remove the handle.

4.   Next remove the chrome collar by gripping it and pulling straight back while twisting (see picture 5).

Step 4: Unscrew the Bonnet

  Grip the bonnet with your hand and twist in a counter-clockwise direction, continue until the bonnet is completely removed.  

Tip: To remove the bonnet of an older valve the channel locks may need to be used as shown in the picture. 

(Caution:  Be careful not to apply excessive force when using the wrench, this will deform the bonnet when using the tongue and grove pliers.)

Step 5: Remove the Old Cartridge.

​Grip the old cartridge and pull straight back towards you,  while applying steady pressure slightly wiggle the cartridge up and down. (Shown in picture 1)

Tip: If the cartridge will not come out, the cartridge can be removed with tongue and grove pliers (shown in picture 2), or the needle nose pliers may also be used.

Step 6: Prepare and Install New Cartridge.

1.  â€‹Put a small dab of faucet grease on your finger and apply the grease to the o-rings of the new cartridge. This will help the cartridge to be installed and seat in the valve body (See picture 1).

2.  Locate the H that signifies the hot side of the cartridge.  When inserting the cartridge, be sure that on the H is on the hot side of the valve body, which, while facing the valve, is on the left hand side. (The H is grey and raised on the cartridge, in picture 2 it was made black for viewing purposes.)

3.   Align the notches of the cartridge with the indents of the valve body (See picture 3).
4.  Once aligned, apply steady pressure on the cartridge until there is no gap between the notches (See picture 3).

Step 7: Replace the Bonnet Turn the Water Back on and Check for Leaks.

1.  Once the cartridge is installed, replace the bonnet.  Tighten by hand only, even if it was necessary to loosen the bonnet with pliers, still tighten by hand (see picture 1).

2.  Slowly open the main shut off valve about half way (see picture 2).  Leave the faucet used to relieve the pressure open while the system is filling.  Once all the air is purged and a steady stream is running out of the spout, shut all faucets off and let the system fill completely.  Turn the main water shut off all the way on.

3.  Inspect the shower valve and make sure there are no leaks (see picture 3).  If there is a drip repeat steps 2-7, if the leak persists call a professional.   

Step 8: Replace the Chrome Collar and Handle.

1.  Next replace the chrome collar.

2.  Finally replace the handle and tighten the set screw.  
    (Caution:  Do Not Over Tighten the Set Screw.)

Once the shower valve is re-assembled and there are no drips you have successfully repaired your shower.   



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    13 Discussions


    Question 1 day ago on Step 8

    I am stuck on step 3. I removed the lever and then unscrewed the set screw. I am unable to remove the handle. You can see the picture I uploaded. The part circled is stuck. Tried to spray wd-40, but no luck. What can I do? Please help. Thanks.


    5 weeks ago

    Thanks for the article. It helped a lot considering every part of my 10-year-old delta monitor shower lever was a bit of a challenge to get off. I did find a strap wrench (<$10) that helped me unscrew the bonnet. They also make a bonnet wrench, but that seems more for a professional plumber.


    Question 2 months ago on Step 1

    Would you know the make and.model.of the shower handle in you tutorial. I recently changed mine, same handle, but had to drill thru the corrosion so it desteoyed the knob. I would like to replace but theres no model number on the handle. Any help would be greatly appreciated. Have a great day

    Joe Bratton

    Question 11 months ago on Step 3

    Screw removed cannot get handle off!!


    1 year ago

    I was able to get through the entire repair but now that everything is back together and leak-free, the hot water does not get hot. It gets warm, but not hot. There are two shower heads and faucets in this shower and the other one gets plenty hot. It is definitely this cartridge/installation. Any thoughts? Thanks in advance.


    4 years ago on Introduction

    I removed the lever and set screw with an allen wrench. I can't remove the piece they go into. Any suggestions?

    1 reply

    Reply 2 years ago

    ? ..into.. ? You mean onto right... go back to step 4 and remove that collar next.


    2 years ago

    In Step 5, only the front half of the cartridge came out. How do I get the other half out without damaging anything?

    1 reply

    Reply 2 years ago

    Halves are separated by twist-lock.. put the front half back in and twist lock it back onto the rear half.. then pull the whole assembly straight out.. rocking it around helps loosen the rear, not spinning it as you found out!

    If that's no longer an option, you have no choice but to collapse the back half, grab a piece of it with vise grips, and yank it out that way.


    3 years ago on Introduction

    How do you work the shower on this delta faucet looks like the 2nd picture


    4 years ago on Introduction

    There are two models of Delta cartridge that look almost identical. They are not interchangeable. The cartridge for the old monitor 1300/1400 series showers has a white plastic top PN# RP19804. The cartridge for the newer 1700 series showers has a grey plastic top PN# DRP32104. Often times these fail because the springs inside lose tension. Try stretching out the springs inside your broken cartridge before buying a new one.


    4 years ago on Step 8

    Not sure, but it might be good to shut of the breaker to the water heater in case the water level in the tank drains below the upper element.