Maxitrol M611R-3/4 Valve

The Maxitrol M611R-3/4 is a precision-engineered modulating gas valve specifically designed for direct-fired burners operating in negative pressure (pull-through) configurations. Unlike standard regulators, this component functions as the core of the Selectra Electronic Gas Flame Modulating System, providing instantaneous, non-fluctuating temperature control without the need for motorized butterfly valves or external mechanical linkages. It features a 3/4" NPT connection and is rated for a maximum inlet pressure of 1/2 PSI. This specific "R" model is equipped with a low fire by-pass adjustment on the right side, allowing technicians to fine-tune the minimum firing rate for optimized burner stability. Constructed for high-demand industrial and commercial HVAC applications, the Maxitrol M611R-3/4 utilizes a counter-spring mechanism to remain seated against the downward pull of negative pressure, ensuring consistent performance in spray booths, makeup air units, and process heating systems. It is compatible with Maxitrol Selectra Series 14, 44, and 94 controls. To ensure proper operation and pressure monitoring, the valve includes a 1/8" NPT tap. For reliable HVAC gas modulation, this valve provides a seamless relationship between control voltage and outlet pressure, maintaining a constant low fire rate even when the main valve is closed.

• Precise Temperature Control: Delivers instantaneous flame adjustment for direct fired negative pressure burners without mechanical lag.
• Enhanced Fine-Tuning: Features a right-side low fire by-pass adjustment for setting the exact minimum firing rate.
• Robust Design: Engineered with a counter-spring to prevent valve opening under suction in pull-through applications.
• Seamless Integration: Fully compatible with Selectra electronic modulation systems and signal conditioners.
• Reliable Pressure Monitoring: Includes a dedicated 1/8" NPT connection for accurate field pressure readings.

What is the difference between the M611 and MR212 series?
The M611 is a dedicated modulator that requires a separate upstream pressure regulator, whereas the MR212 series performs both modulation and pressure regulation in a single unit.

Can this valve be used in positive pressure systems?
No, the M611 series is specifically designed with a counter-spring for negative pressure applications. Using it in a positive pressure system may result in improper seating or erratic gas flow.

Does the mounting orientation of the low fire adjustment matter?
This "R" designated model has the bypass adjustment specifically located on the right side. Ensure your piping layout allows for sufficient tool clearance to access the adjustment screw during commissioning.

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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.