Service any Korky Fill Valve Video Here | https://youtu.be/wL8-KM_28Po Korky QuietFILL Troubleshooting Guide by Korky | http://www.korky.com/fill-valves/quietfill-toilet-fill-valve Hello and Welcome to Korky Toilet repair. This video will help troubleshoot your Korky QuietFill fill Valve if the valve does not shut off, if the valve is hissing or turning on and off by itself while the toilet is not in use, or if the toilet is running. First we have to determine if the water level in the toilet tank is rising above the top of the flush valve overflow tube. If the water level rises above the top of the flush valve overflow tube, the fill valve may not be set to the correct height. Confirm the corner of the fill valve cover lines up with the top of the overflow tube. If the valve is set too high, turn off the water supply and flush the toilet. Adjust the height of the valve by twisting the top half of the valve counterclockwise and push down on the valve until the corner of the fill valve cover lines up with the top of the flush valve. Turn the top of the valve clockwise to lock it in place. If the valve is set to the correct height and the water continues to rise, the valve may need to be serviced. Please refer to our Korky QuietFill servicing video for instructions. If the water level is not rising above the top of the flush valve overflow tube, and the valve is running or hissing, a leaky flapper is likely the cause of the running valve. To test for a leaky flapper, turn the water supply off and mark the water level in the tank with a pencil. Leave the water supply line shut off for at least 30 minutes. If the water level drops below the pencil mark there is a leak in your tank and is an indication that the flapper is not sealing properly This means the flapper is worn and needs to be replaced. In some cases, the flush valve seating surface may be worn or sediment deposits on the flush valve seat are preventing the flapper from sealing. If the flush valve seat feels rough, clean it with a cloth or paper towel. If you are unable to resolve your issue or are in need of more assistance please visit our website or call us at 1-800-528-3553