How to Cure a Dripping Overflow

How to Cure a Dripping Overflow

How to Cure a Dripping Overflow  The level of water in a toilet cistern or in the water-storage cistern in the loft is controlled by a hollow float attached o one end of a rigid arm fitted to the water-inlet valve. As the level rises, the water lifts the float until the other end of the arm eventually closes the valve, shutting off the incoming water.

If the arm is not adjusted correctly, water continues to flow into the cistern until it escapes to the outside through an overflow pipe.

Usually, the solution is to adjust the float arm.

Essential tools:


Adjusting the Float Arm

  • Adjust the float to maintain the optimum level of water, which is about 25mm (1in) below the outlet of the overflow pipe. On some valves the arm is a solid-metal rod. Bend it downward slightly to reduce the water level.
  • The arm on a diaphragm valve has an adjusting screw that presses on the end of a piston. Release the lock nut and turn the screw towards the valve to lower the water level, or away from it to allow the water to rise.

Replacing a Damaged Float

Modern plastic floats rarely leak, but old-style metal floats eventually corrode and allow water to seep into the hollow ball. The float gradually sinks until it won’t ride high enough to close the valve.

Emergency measures

Unscrew the float and shake it to test whether there is water inside. If you can’t replace it for several days, lay the ball on a bench and enlarge the leaking hole with a screwdriver. Pour out the water and replace the float, then cover it with a plastic bag, tying the neck tightly around the float arm.

Thumb-screw adjustment

Some float arms are cranked, and the float is attached with a thumb-screw clamp. To adjust the water level in the cistern, slide the float up or down the rod.

07. December 2010 by admin
Categories: Plumbing | Tags: | Comments Off on How to Cure a Dripping Overflow


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