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Cold Water Reaches the Tub but Will Not Come Out of the Faucet: Unlocking the TCV Check Valve

▶Glossary8
  1. How to Recognize a Locked Check Valve
  2. Where the Check Valve Is Located
  3. How to Unlock the Check Valve
  4. If Cold Water Still Does Not Flow
  5. Related Temperature Problems
  6. Related Guides
  7. Common Questions
  8. Still Need Help?

If cold water is reaching your walk-in tub but the faucet delivers only hot water, the usual cause is the check valve at the cold-water inlet of the thermostatic control valve (TCV). This small one-way valve sits in the housing of the thermostatic valve right where the cold-water supply line connects, and it can stick in the locked position or become blocked by sediment. A local licensed plumber can usually free it. If that does not restore cold flow, Ella ships a replacement thermostatic valve under the published warranty terms, and your plumber installs it.

How to Recognize a Locked Check Valve

The tell-tale sign is water that comes out hot no matter where the temperature dial is set. When the cold line is disconnected at the valve it has pressure, and the inlet screen is clean, yet no cold water passes through the valve. That combination points to the check valve rather than the cartridge. If the dial itself will not turn, start with the guide to a stuck or unresponsive temperature control. If the opposite is happening and there is no hot water at the tub, see why there is no hot water at the tub when the sinks have it.

Where the Check Valve Is Located

The check valve is built into the housing of the thermostatic valve at the port where the cold-water supply line attaches. A spring and a small screen sit in front of it. The screen catches debris coming in from the supply, and the check valve keeps water from flowing backward through the cold side. For a description of the valve itself and how it mixes hot and cold, read what a thermostatic control valve does.

How to Unlock the Check Valve

  1. Shut off the hot and cold supply to the tub.
  2. Disconnect the cold-water supply line from the thermostatic valve.
  3. Remove the spring and the screen from the cold inlet. Rinse the screen and check the inlet for sediment or any other obstruction.
  4. Release the check valve from its locked position so that it moves freely again.
  5. Reinstall the screen and the spring, reconnect the cold line, restore the supply, and test the faucet through the full range of the temperature dial.

Taking a short video of the check valve and the inlet before you reassemble is a good habit. If the valve still will not pass cold water, that video lets the support team confirm the diagnosis and share a reference video and pictures of the check valve with your plumber.

If Cold Water Still Does Not Flow

When unlocking and cleaning do not solve it, the thermostatic valve is replaced. Open a ticket at ellasbubbles.com/support with your serial number, a description of the symptom, and photos or video of the inlet. Ella does not send technicians, so your plumber does the swap. The thermostatic control valve carries a 1-year limited warranty, separate from the lifetime parts warranty on the rest of the tub, and cartridge fouling from calcium, iron or contaminated water is not covered. Fitting an inline filter or mesh on the supply, and cleaning it periodically, protects both the check valve and the cartridge. Cleaning and replacing the cartridge itself is covered in the TCV cartridge cleaning and replacement guide.

Once cold flow is restored, a valve that delivers water at the wrong temperature can often be adjusted rather than replaced. See why the water in the tub is too hot. Crossover between hot and cold while the tub is off is a different fault, and it is covered in why the mixing valve crosses hot and cold when the tub is off.

Common Questions

Why is only hot water coming out of my walk-in tub faucet?
When cold water reaches the tub but never leaves the thermostatic valve, the check valve at the cold inlet is most likely locked or blocked with sediment. Disconnecting the cold line, removing the spring and screen, cleaning the inlet and releasing the check valve usually restores cold flow. If the valve still will not pass cold water, a replacement thermostatic valve is sent under the warranty terms.
Can I unlock the check valve myself or do I need a plumber?
The job involves shutting off the supply and disconnecting a water line, so a local licensed plumber is the safest choice. Your plumber is welcome to call (800) 480-6850 for guidance while the valve is apart. Support can also send a reference video and pictures of the check valve.
Does Ella send a technician to replace the thermostatic valve?
No. Ella ships the replacement thermostatic valve to you, and a local licensed plumber installs it. Free technical support by phone and email is available to your plumber throughout the repair.
Is the thermostatic valve check valve covered under the warranty?
The thermostatic control valve carries a 1-year limited warranty, which is separate from the lifetime parts warranty on the tub. Fouling caused by calcium, iron or contaminated water is not covered, so an inline filter or mesh should be fitted and cleaned periodically. Support verifies coverage when you open a ticket with your serial number.
What if the screen is clean and there is still no cold water?
A clean screen with pressure on the cold line and no flow through the valve is the classic sign of a locked check valve. Try releasing it as described above. If that fails, send a short video of the inlet with your ticket so a replacement can be arranged.

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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