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Adjusting a toilet ball valve

General advice

• Check to see if a service valve is fitted. If a service valve is fitted, the water supply to the cistern can be turned off temporarily. To turn the water off, turn the screw on the service valve a quarter turn.
• If the ball float does not float, it needs to be replaced by a plumber. Contact the repairs hotline to arrange for the work to be carried out.
• You can stop the water flowing temporarily by placing a piece of wood across the top of the cistern and tying the float arm to it.

You need

• Small screwdriver
• Small adjustable spanner

What to do

• Remove the cistern lid and flush the toilet. Then lift the ball float up and check if the water flow stops.
• If the water does not stop, the ball valve needs replacing or rewashering.
• If the water flow stops, the ball valve needs adjusting.
• If the ball valve is the older, metal piston type, carefully bend the float arm to push the ball float down about one inch (25 millimetres). Then let the cistern fill and check the new water level. Adjust the float arm again if necessary.
• If the ball valve is the modern, plastic diaphragm type, loosen the lock nut (turn anti-clockwise), turn the adjusting screw on the float arm a couple of turns (clockwise) and tighten the lock nut. Let the cistern fill and check the new water level. Adjust the float arm further if necessary by repeating the above procedure.