ACT D'MAND KONTROLS System S3-100-PF Series System System includes an electronic circuit board, thermosensor mounted in stainless steel volute, 3/4" CPVC threaded connections and internal check valve Includes (2) stainless steel 3/4" ID, 18" corrugated flexlines with threaded male/female ends and (2) custom machined tooled no lead brass T's Recommended for use with standard plumbing systems in building up to 4,000 sq. ft. with tank water heaters Pipe runs up to 100 lineal ft. with tankless water heaters