Originally Posted by onetonford
They do eventually but they last for years. They sell repair kits for them also. I have had them fail from being used Dry rubber gasket rolls over. Also they have left things in tank when they cut the openings and get caught in the valve. also sawdust.
Any valve can plug, open valve with a bucket under it & wash with a water hose to loosen up plug.
Or use a long rod, once fluid moves, close value drain tank & wash throughout the inside, after washing,
Inspect the inside of valve using a flashlight, repeat if needed. Determine what plugged the valve if possible.
One of the things is female napkins, ect. Hope this helps.