To replace shower valve trim, shut off the water, remove the handle and escutcheon, and fit new trim made for the same valve body, because trim is not interchangeable between valves. Reset the hot limit stop before the handle goes on, then test for leaks with the handle off. Cartridge or valve problems need more than trim.
Can any trim go on any shower valve?
No. The American Standard trim kit sheet opens by naming the exact valve it works with: the Rem pressure balanced shower valve trim kit, model D35100500, is "to be used with" a specific pressure balanced shower valve, model D35000500.191. Moen's sheet for its one handle tub and shower trim carries the same idea. It has a place to write the model number and installation date, and it says the product identification label goes on the back of the escutcheon so the model can be identified later. It also warns that styles and parts vary by model.
Before you shop, identify what is in the wall:
- 1Look at the old trim. Moen's sheet has the installer place a product identification label on the back of the escutcheon, so a Moen trim you are removing may tell you the model.
- 2Keep the model with the valve. Moen's sheet has a spot to write the model number and installation date. If you find an old sheet, keep it.
- 3Ask the maker. Moen says to contact Moen first for installation help or missing parts.
Our pages on how to tell which Moen shower valve you have and pressure balancing versus thermostatic shower valves can help you identify the valve type before you buy anything.
How do you replace the trim, step by step?
The steps below combine the two sheets. Use the instruction sheet for your own trim, because parts differ by model.
- 1Shut off the water. American Standard says to turn off water at the main supply. Moen's sheet adds a caution to turn the hot and cold supplies off before removing the faucet or taking the valve apart, and to open the faucet handle to relieve pressure and confirm the water is completely off.
- 2Remove the handle. Take off the handle and its adapter to reach the escutcheon.
- 3Remove the old escutcheon and note what is behind it. Look at the cartridge and any parts left on the valve. Moen's sheet recommends an access panel behind the valve for future service, so note whether your wall has one.
- 4Check the cartridge orientation. Moen shows the cartridge stem installed with the notch at the end of the stem facing down toward the drain. If hot and cold come out reversed after the job, Moen's troubleshooting table says the cartridge was installed upside down and the fix is to rotate the cartridge stem 180 degrees.
- 5Set the temperature limit stop before you install the trim. More on this below.
- 6Mount the escutcheon. American Standard has you mount the escutcheon holder and gasket to the valve body with screws, mount the escutcheon support, then snap the escutcheon onto the support and push it flush against the finished wall. Moen notes that a gasket on the back of its escutcheon seals against the wall, so make sure the wall is clean.
- 7Install the handle. American Standard has you install the handle adapter on the valve stem and secure it with a screw, then align the lever handle so the lever faces down and tighten the set screw with the supplied hex wrench.
- 8Test. American Standard says to turn the valve off, turn on the water supplies with the handle in the off position and check all connections for leaks, then operate the handle and flush the water lines thoroughly.
### Why does the hot limit stop matter?
Both sheets include a scald protection setting, and it is the step people skip. American Standard describes a hot limit safety stop that limits handle rotation and the amount of hot water allowed to mix with cold, which reduces the risk of accidental scalding. To set it, turn the cartridge stem to the off position, which is the coldest setting, pry free the hot limit stop with a flat blade screwdriver, pull it forward, and rotate it one number counterclockwise to limit the hot water temperature. American Standard says this must be done prior to trim installation. Moen has an adjustable limit stop as well, and its troubleshooting table lists "temperature limit stop out of position" as a cause when the handle does not turn the way it should, with the fix being to position the stop at the desired temperature.
The plumbing code cares about this setting. IPC Section 412.3 says individual shower and tub-shower valves must be balanced-pressure, thermostatic or combination valves, and that they must be equipped with a means to limit the maximum setting of the valve to 120 degrees F, field adjusted in accordance with the manufacturer's instructions so the water does not exceed 120 degrees F. Trim replacement is when that field adjustment gets disturbed, so reset it and check the water temperature at the shower. Our page on what temperature to set a water heater covers the supply side.
What problems does new trim not fix?
Swapping trim changes how the valve looks and feels, not what is inside the wall. Moen's post-installation troubleshooting table lists problems and remedies that show where trim ends and valve work begins:
| Symptom | Moen's cause and remedy |
|---|---|
| Leak or drip from the spout | Grommets not sealing properly. Replace the cartridge. |
| Only hot or only cold | Balancing spool stuck. Replace the cartridge. |
| Handle hard to turn | Cartridge stem difficult to rotate. Replace or lubricate the cartridge. |
| Handle will not install or rubs the wall | Valve set too far back from the finished wall. Contact Moen. |
| Water from the spout and showerhead at once | Restriction between the valve and the spout, or a pipe layout issue. |
| Hot and cold reversed | Cartridge installed upside down. Rotate the stem 180 degrees. |
The row about a valve set too far back matters if you are also changing tile. Moen's installation steps show the valve set so that a plaster ground sits flush with the finished wall, which puts the valve at the correct position to accept the trim. If a remodel changes the wall thickness, the valve depth may need to change too. Our page on what goes behind tile around a tub covers what changes when the wall is rebuilt.
If water is already leaking behind the wall, trim will not help. Our page on a leaking shower valve behind the wall shows the signs.
When do you need a plumber, and a permit?
Call a plumber when the job goes past the trim: a cartridge that will not come out, a valve body that is loose, corroded or set at the wrong depth, or any leak inside the wall. Moen's sheet describes valve replacement, which needs the wall opened and the supplies reconnected, in copper, IPS, PEX or CPVC. Moen notes that specific rough-in fittings are not supplied and that all local building and plumbing codes should be followed, and it suggests testing for leaks before sealing the walls.
On permits, the City of Phoenix exempts clearing stoppages, repairing leaks, and replacing valves or fixtures with compliant new ones, but says a permit is required to relocate any valves, pipes or fixtures. A trim swap on the same valve is a like-for-like replacement. Moving the valve is not. Other Valley cities have their own rules, so check with yours.
HQ Plumbing and Air is licensed and insured, takes emergency calls 24/7, and gives free estimates with an upfront price before work starts. See our plumbing services.