Chemical feed systems rely on small check valves to control injection flow and help prevent water or chemical backflow. The Pentair Pool Products IChem/IpH Injection Check Valve [1/4" Jayco x 1/2" MPT] (522513Z) is a replacement injection check valve for compatible Pentair iChem and iPH chemical automation systems. This valve is useful when chemical feed is inconsistent, the injection point is leaking, or the existing check valve no longer seals properly. Replacing the injection check valve helps maintain controlled chemical dosing and protects equipment from unwanted backflow through the chemical line. For compatible Pentair iChem and iPH systems 1/4 inch Jayco x 1/2 inch MPT reference Helps control chemical injection flow Useful for leaking or failed injection points Supports reliable automated water chemistry treatment