Maxitrol MR212E-1212 Valve

The Maxitrol MR212E-1212 is a heavy-duty 1 1/2" NPT modulating gas valve and regulator engineered specifically for direct fired negative pressure burners. Designed as the primary control component for the Selectra electronic gas flame modulation system, this valve combines high-precision modulation and pressure regulation into a single unit. It eliminates the need for an external mechanical actuator or motor-driven butterfly valve, providing instantaneous response and non-fluctuating temperature control. With a 5 PSI maximum inlet pressure rating, it is robust enough for demanding industrial makeup air units and process heating applications. Pro tip for the field: the MR212 series features a counter-spring design to ensure the valve remains closed against the downward pull of negative pressure systems. This valve is factory-set for -1.5" w.c. but is field-adjustable up to -3.5" w.c., allowing technicians to fine-tune the minimum firing rate via the adjustable bypass for optimal combustion efficiency and burner stability across Natural, LP, and mixed gas types.

• Dual-Function Design: Integrates both gas pressure regulation and modulation, reducing the footprint and complexity of the gas train by eliminating separate upstream regulators.
• Negative Pressure Compatibility: Dedicated pull-through application design prevents unintentional valve opening under high-vacuum conditions.
• Infinite Flame Adjustment: Provides seamless, continuous modulation rather than stepped firing, ensuring precise discharge air temperature control in makeup air systems.
• High Pressure Resilience: Rated for a maximum emergency exposure of 12.5 PSI, offering superior safety margins for industrial gas burners.
• Low Fire Stability: Features an adjustable bypass to maintain a consistent minimum firing rate regardless of the main valve position.

Does this valve require an external amplifier?
Yes, the Maxitrol Selectra system typically requires a companion amplifier (like the A1094 or AD1094) to provide the 0-20V DC signal needed for operation.

Can I use the MR212E-1212 for positive pressure applications?
No. This specific model is strictly for negative pressure burners. For push-through or positive pressure systems, you must specify the MR212E-1 model.

What should I check if the unit stays at low fire?
First, verify that you have 10-13 Volts DC at the modulator head terminals. If voltage is correct, inspect the plunger for debris or ensure the regulator ports in the upper plate aren't restricted by pipe dope or metal shavings.

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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.