Maxitrol MR212D-2-1212 Valve

The Maxitrol MR212D-2-1212 is a high-performance 1-1/2" NPT modulating gas valve and regulator specifically engineered for direct-fired (negative pressure) burners. As a critical component of the Selectra Series electronic gas flame modulating system, this valve eliminates the mechanical lag associated with motor-driven butterfly valves, providing instantaneous response and non-fluctuating temperature regulation. It is designed to handle a maximum inlet pressure of 5 PSI, making it suitable for high-demand industrial make-up air heaters and process drying equipment.

This negative pressure gas valve features a specialized counter spring mechanism that ensures positive closure against vacuum forces. Factory-calibrated for systems operating at -1.5" w.c., the MR212 can be field-adjusted to accommodate up to -3.5" w.c. of suction. The integrated modulator-regulator design maintains a consistent manifold pressure, ensuring stable firing rates even when upstream supply pressures fluctuate. For contractors servicing industrial oven controls or HVAC air handlers, the Maxitrol MR212D-2-1212 provides the precise dual pressure settings required for optimal combustion efficiency and repeatable thermal performance.

Key Benefits for Technicians:

• Precision Modulation: Uses a frictionless modulator/regulator design for smooth, precise control without the maintenance headache of mechanical linkages or motors.
• High Pressure Capability: Rated for 5 PSI maximum inlet pressure, significantly reducing the need for additional step-down regulators in many commercial footprints.
• Negative Pressure Optimized: Specifically balanced for pull-through burners to prevent inadvertent valve opening during startup or high-vacuum cycles.
• Field Versatility: Direct Maxitrol Selectra series compatibility allows for easy integration with existing amplifier systems and discharge air sensors.
• Stable Output: Maintains a steady gas-to-air ratio, improving the reliability of the direct-fired heating process and reducing nuisance flame-outs.

Common Questions:

Can this valve be used on positive pressure systems?
No, the MR212D-2-1212 is internally balanced with a counter spring specifically for negative pressure applications. Using it in positive pressure setups may result in improper regulation and safety risks.

What is the maximum vacuum this valve can handle?
While factory-set at -1.5" w.c., the internal mechanism is adjustable to maintain stable operation up to -3.5" w.c. vacuum.

Does this require a separate regulator?
This unit functions as both a modulating valve and a pressure regulator, though a manual shut-off and high-pressure regulator may still be required based on your local codes and supply pressure.

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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.