Is your toilet cistern overflowing? Or the overflow from the loft tanks?
This may mean that the ball inside it is damaged and not rising enough, or that the float arm needs adjustment.
Take a look inside. If the ball is lower in the water than one-third of its diameter, it probably has a crack or hole in it. Unscrew it from the float arm and shake it, to hear if it contains water. If it does, buy a new one from a hardware shop or plumbers’ supplier and screw it on.
If the ball is not damaged, try adjusting the float arm by means of the screw adjuster, if there is one; if not, slightly bend the metal arm. Make sure that when the arm is adjusted the water level remains below the overflow pipe.
The valve itself may have collected deposits and need cleaning, or it may need a new washer. Turn off the water supply. Then, using pliers, remove the slit pin that attaches the arm to the valve. Unscrew the valve cap and take out the piston, valve washer and piston cap. Use wire wool to remove deposits In or on the piston. Check the valve washer. If it is severely corroded, replace it, a new one can be bought from a hardware shop.
Check the rubber washer on the other side of the valve casing. If it is worn, replace it.
Put the piston back together again and then smear it lightly with petroleum jelly, before inserting it back into the valve casing.
JD plumbing can help with any of your plumbing problems. For advice or a free quote please get in touch