Honeywell 310668 Diaphragm

The Honeywell 310668 is a heavy-duty, 5-inch high temperature silicone diaphragm specifically engineered for legacy pneumatic systems. Built to withstand the rigorous thermal demands of steam and high-pressure hot water service, this replacement diaphragm is compatible with Honeywell MP953A, MP953C, and MP953E valve actuators. By replacing a worn or ruptured component with this genuine OEM part, technicians can eliminate air leakage and ensure precise proportional control of HVAC control valves. Its specialized silicone construction facilitates low hysteresis and consistent rolling action, preventing the common "stick-slip" behavior associated with degraded elastomers in pneumatic valve actuators. Whether you are maintaining a V5011 or V5013 assembly, this 5" rolling diaphragm provides the mechanical integrity required for accurate stem positioning in high-ambient environments. This "old style" flat-edge design is the professional standard for restoring proportional pneumatic control in commercial building automation systems without needing to replace the entire actuator housing.

• High-Temperature Resilience: Engineered with silicone elastomer to maintain flexibility and seal integrity in high-heat steam and hydronic applications.
• Optimized Compatibility: Direct fit for 5-inch Honeywell MP953 series actuators (A, C, and E models), ensuring factory-spec performance.
• Enhanced Control Precision: Features a rolling diaphragm design that reduces hysteresis for smoother, more accurate valve modulation.
• System Longevity: Prevents pneumatic pilot air loss, reducing duty cycles on compressors and extending the life of the HVAC actuator.

Is the Honeywell 310668 compatible with the newer MP953D or F models?
No, this specific version is designed for the 5-inch diameter "old style" MP953A, C, and E models. For MP953D and F actuators, which typically use a 7-inch diaphragm or different EPDM materials, a different part number is required.

What symptom indicates this diaphragm needs replacement?
The most common indicator is a persistent air hiss from the actuator vent or a failure of the valve to reach its full stroke (either 2-7 psi, 4-11 psi, or 8-12 psi ranges) despite receiving full branch pressure from the pneumatic thermostat.

Does this diaphragm support steam valve applications?
Yes, because it is the high temperature silicone variant, it is specifically rated for the elevated temperatures found in steam-to-water heat exchangers and steam coil actuators where standard neoprene diaphragms would fail prematurely.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.