The Spence Engineering D550 Pilot is a heavy-duty, spring-operated pressure pilot designed to interface with Type E and Type C main valves for high-accuracy steam regulation. Constructed with a rugged cast iron body, this normally closed pilot is specifically engineered for secondary pressure control in steam heating systems and industrial vapor applications. It features a 5-50 PSI spring range, allowing contractors to field-adjust delivery setpoints with a stainless steel diaphragm and packless construction that eliminates typical maintenance issues associated with stem packing leaks. For technicians running high-demand boiler rooms, the D550 provides a consistent 1 PSI regulation accuracy, ensuring that downstream processes remain stable despite fluctuations in initial inlet pressure. Its inline design simplifies the installation of pilot-operated regulators, while the Inconel adjusting spring maintains tension integrity under the continuous thermal stress of 450°F maximum operating temperatures. Key Benefits Stable Output: Maintains accurate pressure regulation within ±1 PSI, critical for sensitive steam equipment. Durability: Cast iron construction and stainless steel internals provide long-term reliability in high-cycle industrial steam processes. Ease of Maintenance: Packless design and modular internals allow for rapid service and diaphragm replacement without removing the valve from the line. Versatile Compatibility: Seamlessly integrates with the Spence Type E main valve to form a complete pressure-reducing station. Common Questions What is the maximum inlet pressure for the Spence D550 pilot? The D550 cast iron pilot is rated for a maximum inlet pressure of 250 PSIG and a maximum temperature of 450°F. How do I adjust the delivery pressure on this pilot? The delivery pressure is adjusted by turning the top nut on the 5-50# spring range assembly. Tightening the nut increases the downstream pressure setpoint. Can this pilot be used for air or water service? Yes, the D550 is suitable for fluid, gas, and vapor applications, though it is most commonly utilized as a steam pressure pilot. This item is not eligible for free shipping. 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.
