Maxitrol M520H-3/4 Gas Valve

The Maxitrol M520H-3/4 is a precision-engineered modulating gas valve specifically designed for LP gas applications requiring a wider modulation span. Built for compatibility with atmospheric burners and direct-fired systems, this 3/4" NPT valve operates within the Selectra electronic gas flame modulation system to provide instantaneous, non-fluctuating temperature control. Unlike standard regulators, the M520H functions as a modulator that requires a separate upstream pressure regulator. It is optimized for "H" suffix applications where the outlet pressure exceeds 7" w.c., featuring a factory-set minimum outlet pressure of 1.75" w.c. to ensure stable combustion at low-fire settings. The 3/4 inch NPT gas valve construction supports a 1/2 PSI maximum inlet pressure, making it a staple for HVAC contractors servicing industrial space heaters and commercial process heating equipment. By utilizing a 24V AC power requirement and a magnetic plunger assembly, it eliminates the need for mechanical butterfly valves, ensuring reliable liquid propane gas control in demanding environments.

Key Benefits

• High-Span Modulation: Specifically tuned for LP gas with a modulation span capable of reaching up to 10" w.c., preventing hunting in high-pressure applications.
• Precision Temperature Control: Delivers immediate response to voltage changes from Selectra amplifiers for tight setpoint maintenance.
• Durable Construction: NPT threaded connections and robust internal diaphragms designed for long-term service in commercial heating system components.
• Atmospheric Burner Compatibility: Ideal for indirect fired units, providing stable low-fire bypass settings and consistent high-fire performance.

Common Questions

Does this valve require an external regulator?
Yes. As a modulator-only valve, a separate upstream pressure regulator must be installed in the gas train to manage the 1/2 PSI max inlet pressure.

Can the M520H-3/4 be used for Natural Gas?
While the M520 series is compatible with various gases, the "H" models are specifically factory-configured with the springs and bypass settings required for the higher pressures associated with LP gas applications.

What is the proper mounting orientation?
For optimal plunger operation and to prevent debris accumulation, this valve should be mounted in an upright position within a horizontal run of pipe.

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.