Are you a Professional Plumber Contractor looking for Fluidmaster's PRO Products?


Back To Fluidmaster Fix It Zone

Fluidmaster Fix It Zone


Toilet Fill Valve Runs Non Stop

If your 400 Series fill valve will not turn off, follow these steps:

  1. Check for debris in the seal area by removing the top cap assembly.

    1. Turn off water supply and flush the tank.

    2. Reach inside the tank with your right hand under the float cup and lift it up. With your right hand hold onto the gray shaft keeping the float cup all the way up. Do not allow the float cup to drop or valve shaft to turn.

    3. Place your left hand on the top of the valve cap and while placing your left hand thumb on the side of the arm coming out of the top. Turn the cap and lever counter clockwise 1/8th of a turn to unlock. You should be able to lift off the cap and lever from the valve body.

    4. Once the cap assembly has been removed inspect for debris on the seal (rubber disc with pin coming through) and also the valve portion still in the tank.

    5. Hold a cup upside down over the exposed opening of the valve and turn on the water supply full force for 10-15 seconds, allowing the pressure to free any debris inside the valve inlet.

    6. Reassemble the top of the valve by placing the cap arm next to the refill tube. To lock, press the cap down while turning it and the arm clockwise.

  2. If you find no debris in the valve, then the seal may need to be replaced.

  3. If your valve is more than 2 years old, replace the seal (located in the cap assembly). You can purchase a new seal Model # 242 at your local hardware store.

The bottom hand is lifting up on the float cup which raises the black arm under the top cap. The top hand is gripping the cap while the thumb is pressing on the raised lever arm.