HotSpring Spa This 3/4" water check valve is installed in the inlet side of the circulation pumps plumbing to prevent the back flow of water through the circulation pump once the jet pump is activated. All water check valves have arrows stamped on the outside to indicate the direction of flow which should be pointer towards the circulation pump. These low flow water check valves come in two sizes (1/2" #70173 & this 3/4").
