What is a cast iron check or flapper valve?
A check valve is a valve that has a disc that is in the free hanging closed position. Since this valve is always closed it relies on the force of the waste water exiting the home to force the solid waste past the closed valve. What usually happens is that he water passes through, while the solid waste stops at the valve. Some units will block frequently requiring immediate removal of the obstruction. But, what usually happens is that the water passes through, while the solid waste stops at the valve, forcing it and holding it in the open position. Unfortunately, many people find this out when they begin to flood.
