Maxitrol M611-3/4 Valve

The Maxitrol M611-3/4 is a precision-engineered modulating gas valve specifically designed for direct fired burners operating under negative pressure conditions (pull-through applications). This 3/4" NPT component utilizes a specialized counter spring mechanism that ensures the valve remains securely closed against the downward pull of negative pressure, common in make-up air units and industrial space heating. With a 1/2 PSI maximum inlet pressure rating, this valve provides a linear relationship between the electrical control signal and the gas flow rate, allowing for precise temperature control and steady-state burner performance without the hysteresis found in mechanical butterfly valves.

Built for durability in commercial environments, the Maxitrol M611-3/4 features an adjustable low fire bypass orifice, enabling technicians to fine-tune the minimum firing rate during low-load conditions. As a dedicated modulator, it must be installed downstream of a separate upstream pressure regulator to maintain stable inlet pressure. It is fully compatible with Maxitrol Selectra series amplifiers (such as the A1494 or AD1094) and SC11 signal conditioners, facilitating seamless integration into existing HVACR burner control systems.

• Designed exclusively for negative pressure applications to prevent accidental opening from suction.
• Supports instantaneous response to control signals for non-fluctuating discharge temperatures.
• Includes a 1/8" NPT vertical vent outlet for standard field piping requirements.
• Provides infinite flame adjustment for superior combustion efficiency and energy savings.
• Reliable performance across an ambient temperature range of -40°F to 125°F.

Does this valve provide 100% safety shut-off?
No, the Maxitrol M611-3/4 is a modulating control valve and does not provide redundant seats for safety shut-off. It must be installed in sequence with a dedicated safety shut-off valve.

When should I adjust the low fire bypass?
The low fire adjustment should be verified whenever the high fire manifold pressure is changed to ensure a stable minimum burner flame and prevent flame failure at the lowest modulation point.

Can I use this for propane gas applications?
Yes, this valve is rated for use with natural, manufactured, mixed, and LG gas-air mixtures typical in industrial heating.

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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.