How do I remove and replace the thermostatic valve cartridge?

To remove the thermostatic valve cartridge on an Ella walk-in tub, shut off the hot and cold supplies, lift off the control handle, remove the cover plate, TCV governor, washers and escutcheon plate, unscrew the metal collar from its flat wrench area, and unscrew the cartridge. Cleaning comes before replacing, because a cartridge fouled with calcium, iron and sediment often works again once its screens are brushed clean, and Tub Fills Only Scalding or Only Cold and Will Not Mix to Warm explains why that fouling is the usual reason the valve stops mixing. This page gives the full removal and reassembly sequence shown in the TCV video, the plastic collar step for the 5-piece faucet, and where the written guide lives.

Confirm You Have the Thermostatic Valve

Ella drills each tub for the faucet chosen on the order, and three different cartridges are used across the faucet packages, so check which faucet is on your deck before buying any part.

• Thermostatic faucet package. A temperature dial on a chrome deck plate with a built-in Thermostatic Control Valve (TCV) that blends hot and cold to a set temperature, plus two diverter valves, one for the spout and one for the sprayer. Its cartridge is the thermostatic one covered on this page.
• 5-piece fast-fill faucet. Separate hot and cold handles with red and blue caps and the diverter as the middle lever. Each handle has its own cartridge under a plastic collar. This faucet is not thermostatic.
• 2-piece fast-fill faucet. One spout with a lever handle and a diverter button under the spout, with one cartridge in the spout housing.

Only a tub ordered with the thermostatic package has a TCV; the standard sets mix by hand, as Does the Ella Fast-Fill Faucet Hold a Set Water Temperature Automatically? explains. Water that jumps between scalding and cold with nothing in between points to the TCV cartridge. Hot and cold meeting while the tub is off is a crossover, and the cartridge is the first place to look, though the hand shower's check valve is the other path, as Why Does the Mixing Valve Cross Hot and Cold When the Tub Is Off? walks through.

Before You Start

• Close both shut-off valves at the tub so no hot or cold water reaches the faucet.
• Have an Allen wrench for the handle bolt, channel locks or vice grips for the metal collar, a soft brush, some CLR and lithium grease ready.
• Lay the small parts out in the order they come off, because they go back in reverse: handle, cover plate, governor, washers, escutcheon plate, collar, cartridge.
• Whatever you tighten, tighten securely without over torquing. Every Ella procedure repeats that instruction.

Removing, Cleaning and Refitting the TCV Cartridge

The first video on this page shows this job from start to finish, and the steps it follows are:

1. After shutting off the water supply, loosen the Allen bolt on the control handle and lift the handle off. If there is a colored cap over the bolt, take that off first.
2. Loosen and remove the cover plate.
3. Slide off the TCV governor.
4. Remove all the washers, then remove the escutcheon plate.
5. Loosen the metal collar with channel locks or vice grips, gripping only the unthreaded flat wrench area so the threads are not damaged, and unscrew the collar completely.
6. Unscrew the cartridge.
7. Check and clean the intake screens. Sediment, salt and other debris build up on them; a soft brush with some CLR cleans them. Check the bottom of the cartridge so it is also free of debris and sediment.
8. Lightly lubricate the gaskets with lithium grease, then replace and re-tighten the cartridge.
9. Carefully replace the outer collar and tighten it securely without over torquing.
10. Replace the escutcheon plate, then the washers, then the TCV governor.
11. Put the control handle back on and secure it with the Allen bolt.
12. Open both shut-off valves fully and confirm the fill temperature responds to the dial.

Whenever the TCV is serviced, also inspect the water intake screen on the bottom, including the screen and the check valve, because calcification and debris there can impede proper water flow. The same soft brush and CLR clean it. If the cleaned cartridge still will not mix, fit a new cartridge using the same sequence; if the valve itself has failed, replacing the whole TCV is the recommended repair.

Is There a Manual for the Valve?

Yes. The Thermostatic Control Valve page on ellasbubbles.com walks through disassembling and cleaning the cartridge step by step and offers a downloadable Cleaning Thermostatic Control Valve PDF guide, and the TCV Valve Replacement video on this page shows the same job. Support can also send the video link directly. For a second hand tub with no hot water at the faucet, send photos of the faucet and of the valve along with the model and serial number through ellasbubbles.com/support or by calling (800) 480-6850, so the team can see what is actually installed before any part ships.

Getting the Plastic Cover Off Under a 5-Piece Handle

If the cover under your handle is plastic rather than a chrome cover plate, you have the 5-piece fast-fill faucet, and that plastic collar comes off only once the handle is clear. The second video shows the sequence: remove the red or blue cap on the handle, loosen the bolt beneath it with a 3 millimeter Allen wrench, lift off the handle, then lift the plastic collar off, which leaves the cartridge exposed. Loosen and remove the cartridge with a 17 millimeter socket wrench, check for debris, foreign objects or calcification, clean with a soft brush and rinse, then replace the cartridge and tighten without over torquing. Put the plastic collar back, set the handle facing the correct way, red on the left for hot and blue on the right for cold, tighten the Allen bolt firmly and replace the colored cap. The 2-piece faucet releases its cartridge with a brass locking collar instead of a socket; both standard sets are covered step by step in How do I replace the faucet cartridge on an Ella walk-in tub?. If you have the thermostatic set with the chrome deck plate and are unsure which part you are looking at, send a photo through ellasbubbles.com/support before taking anything apart.

Warranty, Parts and Who Does the Work

The TCV carries a 1-year limited warranty and is excluded from the lifetime parts warranty. Cartridge fouling caused by calcium, iron or contaminated water is not a covered defect, which is why an inline filter or mesh must be fitted on the water lines and cleaned periodically; that protection is required for the TCV, and it keeps a new cartridge from fouling the way the old one did. Fast-fill faucet parts, including the 2-piece and 5-piece cartridges, are covered under the lifetime parts warranty, so a worn cartridge there is requested through support rather than sourced locally. When a part is covered, Ella ships it under the warranty and a local licensed plumber does the labor; Ella does not send technicians. If cleaning the thermostatic cartridge becomes a recurring chore in a hard water area, tech support may suggest switching to the Ella 5-piece fast-fill faucet, which has no thermostatic cartridge to foul but does not hold a set temperature on its own.

Watch: Ella's Bubbles: Cartridge Replacement 5 Piece with chapters and a full transcript.

Related Guides

• How Do I Adjust the Maximum Temperature on a Walk-In Tub Thermostatic Valve?
• Replacing an Older TCV: 1/2 Inch vs 3/4 Inch Supply Inputs, the Hidden Deck-Plate Screw, the Governor Button and What Is Supplied
• How Do I Replace the Faucet Cartridge on My Walk-In Tub?

Common Questions