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Replacing a Failed Thermostatic Control Valve: Cleaning First, Cartridge Versus Whole Valve, and How to Order

Updated September 2026

▶Glossary10
  1. Symptoms of a Valve Problem
  2. Try Cleaning the Cartridge First
  3. Cartridge or Whole Valve
  4. Placing the Order
  5. Warranty on the Valve
  6. Installing the New Part
  7. Related Guides
  8. Related Videos
  9. Common Questions
  10. Still Need Help?

A replacement thermostatic control valve or cartridge is often available for Ella tubs that shipped with a thermostatic faucet package. Whether you need only the cartridge or the complete valve depends on which generation of faucet your tub has, so the team confirms the exact part and its current availability from a photo before anything is ordered. Replacement parts are ordered by phone with a credit card and a shipping address, or through the parts order form. Before ordering, it is worth trying a cartridge cleaning, since a fouled cartridge causes the same symptoms as a failed one.

Symptoms of a Valve Problem

The most common reports are water stuck very hot, and hot water flowing with no cold water coming through. Both point to the thermostatic cartridge inside the valve rather than to the faucet spout or the diverter. If the problem is a drip or a leak instead, start with identifying your faucet and the right replacement.

Try Cleaning the Cartridge First

The thermostatic cartridge is sensitive to calcium, iron, and debris in the supply water. Mineral buildup stops it from mixing correctly, and this fouling is not a warranty defect. Ella has videos showing how to disassemble, clean, and reinstall the cartridge, and the team can send the links for your faucet. An inline filter or mesh screen on the supply line, cleaned periodically, protects the cartridge once the problem is solved.

Cartridge or Whole Valve

  1. Take a clear photo of the valve body, the knob, and the supply connections, and note your tub's serial number from the label behind the magnetic access panel next to the door.
  2. Send the photos through ellasbubbles.com/support or call (800) 480-6850. The team matches the part from the photo.
  3. Older tubs used a thermostatic valve with half-inch inlets. That valve body has been discontinued, and in some cases the cartridge alone is the replacement for those units. A missing set screw can be matched at a hardware store.
  4. Current tubs use a three-quarter-inch thermostatic valve, and the team confirms whether the complete valve or the cartridge is the right part for yours.
  5. If a valve for an older faucet can no longer be matched, the thermostatic faucet can be replaced with an Ella fast-fill faucet, and the team will explain what that involves.

Placing the Order

See ordering a replacement part by order form or phone and how to order replacement parts. Some Ella dealers can also help with thermostatic valves and service, so ask your dealer if you have one nearby. Tracking is sent when the part ships, and this article covers tracking and shipping questions.

Warranty on the Valve

The thermostatic control valve carries a one-year limited warranty and is excluded from the lifetime parts warranty. Cartridge fouling from calcium, iron, or contaminated water is not covered, which is why cleaning and filtering matter. If the valve fails within its first year, open a ticket with photos and the serial number instead of ordering. For other frequent parts questions, see common questions about replacement parts.

Installing the New Part

Ella ships the part, and a local licensed plumber does the labor. The same videos used for cleaning show the cartridge change, and technical support is available by phone to your plumber during the work.

Chapters in this video
  1. 0:00 Remove Control Handle And Cover The technician removes the control handle and cover plate after shutting off the water supply.
  2. 0:16 Remove Escutcheon Plate And Collar The technician removes the washers, escutcheon plate, and then unscrews the metal collar.
  3. 0:33 Unscrew Cartridge And Clean Screens The technician unscrews the cartridge and cleans the intake screens and cartridge bottom.
  4. 0:56 Replace Cartridge And Reassemble The technician lubricates and replaces the cartridge, then reassembles the collar, escutcheon plate, and control handle.
  5. 1:30 Inspect Water Intake Screen The technician inspects and cleans the water intake screen and check valve for calcification and debris.
Chapters in this video
  1. 0:00 Remove Handle And Collar The technician removes the colored cap, loosens the bolt with an Allen wrench, and lifts off the handle, then removes the plastic collar.
  2. 0:19 Remove And Clean Cartridge The technician uses a socket wrench to loosen and remove the cartridge, then checks for debris and cleans it with a soft brush.
  3. 0:37 Replace Cartridge And Collar The technician replaces the cartridge, tightening it without over-torquing, and then replaces the plastic collar.
  4. 0:51 Reattach Handle And Cap The technician puts the handle back on in the correct position, tightens the Allen bolt firmly, and replaces the colored cap.

Common Questions

Is the thermostatic control valve still available for my tub?
Often yes. Some older valve bodies have been discontinued while the cartridge alone remains available, and the current three-quarter-inch valve is offered as a part. Send a photo and the team confirms which part fits and whether it is in stock.
Can I just replace the cartridge instead of the whole valve?
Usually yes. The cartridge is the part that fails when water will not mix correctly, and it can be changed without removing the valve body. The team will tell you if your valve needs the full assembly.
Is a stuck or fouled valve covered under warranty?
The valve has a one-year limited warranty. Fouling from calcium, iron, or contaminated water is excluded, so a cleaning is the first step, and an inline filter is recommended to protect the replacement.
How do I pay for and receive the part?
Call the team with your serial number, a credit card, and a shipping address, or use the parts order form. Tracking is emailed once the valve or cartridge ships.
Can a local plumber install the valve for me?
Yes. Any licensed plumber can change the cartridge or the valve, and the team can send the how-to video and answer questions by phone while the work is done.

Still Need Help?

Open a ticket at ellasbubbles.com/support or call (800) 480-6850 and have your model and serial number ready.

Related guides

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