The Johnson Controls D-251-6003 is a high-performance replacement diaphragm specifically engineered for pneumatic actuator maintenance and repair

This universal interchangeable hub is optimized for 3-blade

the E9-16 is technically identical to and interchangeable with HK-E9-16 and HKN-E9-16 part numbers

37" WC setpoint is accurate to factory specs

contains activated alumina for acid removal

Lochinvar & A.O. Smith 100163257 Bypass Assembly 322056-301 The Johnson Controls D-251-6003 isThe Lochinvar & A. O. Smith 100163257 Bypass Assembly is a critical OEM component engineered for precise flow management in high efficiency pool and spa heating systems. Built to withstand the rigorous demands of commercial and residential hydronic applications, this 1 2" NPT bypass kit ensures optimal heat exchanger performance by regulating water velocity and preventing thermal shock. This assembly is a direct replacement part designed specifically