Maxitrol MR251D-1 1/2 Regulator

The Maxitrol MR251D-1 1/2 regulator is a dual-function modulator-regulator valve engineered for critical indirect-fired atmospheric burner applications. As a core component of the Selectra electronic gas modulation system, this 1 1/2" NPT unit eliminates the need for external motors or butterfly valves by providing precise, instantaneous temperature control through its internal plunger-diaphragm assembly. Designed for high-demand environments requiring elevated outlet pressures, the MR251D-1 1/2 handles a maximum 5 PSI inlet pressure while maintaining non-fluctuating gas flow. It is compatible with natural, manufactured, mixed, and LP gases, making it a versatile choice for specialized process heating, large-scale baking, and industrial drying systems. Techs should note the negative pressure design, which utilizes a counter-spring to ensure positive closure against pull-through forces, ensuring reliable low-fire bypass settings and steady high-fire gas modulation without hunting or mechanical lag.

• Dual-Function Design: Integrates both pressure regulation and electronic modulation into a single 1 1/2" NPT gas valve body, reducing installation footprint and complexity.
• Precise Burner Control: Specifically optimized for atmospheric burners where consistent, higher outlet pressures are necessary for process stability.
• Robust Pressure Rating: Accommodates 5 PSI maximum inlet pressure, providing the headroom needed for industrial gas loops and high-flow systems.
• Negative Pressure Compatibility: Features an engineered counter-spring to maintain valve integrity in "pull-through" combustion setups.
• Multi-Fuel Support: Factory-rated for a wide range of fuel gases, including Natural Gas and Propane (LP) mixtures.

Common Questions

Is an external motor required for this valve to modulate?
No, the MR251D series uses an internal solenoid-driven plunger to modulate flow, removing the need for external linkages, motors, or butterfly valves.

Can this be used in systems with negative pressure?
Yes, this specific model is designed for negative pressure applications and includes a counter-spring to ensure the valve remains closed when the system is not firing.

What is the maximum allowable inlet pressure for the MR251D-1 1/2?
The unit is rated for an absolute maximum inlet pressure of 5 PSI, making it suitable for both standard and moderately high-pressure gas lines.

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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.