a. Check if there is any distortions or crack at the bottom of the exterior toilet tank near the flush valve.
b. Insure that the installation surface of the flush valve is uneven.
c. Check if flush valve is installed in the proper postion.
d. Insure the flush valve hardware (lock nut) is firmly tightened.
e. Make sure flush valve gasket and seal are not distorted or if there is any debris on the surface.
f. Check to insure that there is not any space between the flush valve's rubber seal and the sealing surface.
g. The water lever is too high, over overflow pipe or tank lever hole.
h. Length of flush valve chain is too short.
i. Inlet valve is constantly refilling the bowl.
j. Ceramic bowl problem, crack breakage etc.
II) Water will not shut off
a. Check if fill valve float moves up and down freely. If not, the wall of the ceramic tank or other components inside the tank may be impeding the float.
b. Remove fill valve cap, check if there is any distortion, breakage or impurities to the seat of the valve. (sealing surface).
c. Check if fill valve's inlet tube is cracked.
d. Refill tube is inserted lower than water level.
III) Fill valve not filling water
a. Water pressure is too low or water supply valve is not turned on.
b. Check to insure filter is not clogged with debris.
c. Check to insure fill valve float moves up and down freely. If not, the wall of the ceramic tank or other components inside the tank may be impeding the float.
d. Inlet tube problem.