Maxon 125SMA11AA11BB21A0 Gas Valve

The Maxon 125SMA11AA11BB21A0 is a heavy-duty, 1 1/4" industrial gas shut-off valve designed for high-reliability combustion systems. This electromechanical safety valve features a robust cast iron body and a 2-way, normally closed configuration, ensuring instantaneous fuel shut-off in less than one second upon power interruption. Engineered with Buna-N body O-rings and bumpers, the 125SMA series is optimized for general-purpose gas service, providing a Standard Port flow capacity and a Cv of 45 to maintain consistent pressure regulation in 1.25-inch NPT threaded piping runs.

This automatic reset valve is powered by a 115VAC 60Hz solenoid and motor assembly, featuring a 6-second motor timing for controlled opening cycles. For advanced system monitoring, it includes VOS1/VCS1 switch options, providing integrated proof of closure (VCS) and proof of open (VOS) signals to your burner management system. The assembly is housed in a NEMA 4 enclosure, making it suitable for demanding mechanical rooms where protection against dust and water is required. With a 100 PSIG maximum operating pressure differential (MOPD) and internal Trim Package 1, this Maxon valve is a standard-tier solution for contractors and technicians maintaining industrial boilers, furnaces, and process heating equipment.

Key Benefits

• Fast-Acting Safety: Internal spring-loaded mechanism ensures positive gas shut-off in under one second during power loss.
• System Integration: VOS1/VCS1 auxiliary switches allow for seamless interlocking with safety circuits and DCS control platforms.
• Durable Construction: The cast iron body and metal-to-metal seating are designed to handle rigorous industrial thermal cycles.
• Environmental Protection: NEMA 4 rating ensures internal components remain shielded from moisture and debris in the field.
• Automated Operation: The motorized automatic reset facilitates remote restarts without requiring manual intervention at the valve.

Common Questions

The VOS1 (Valve Open Switch) signals when the valve has reached its fully open travel limit, while the VCS1 (Valve Closed Switch) provides a proof of closure signal. These SPDT switches are critical for meeting safety codes and confirming valve status to the main control panel.

Yes, the Maxon 125SMA is compatible with natural gas, propane (LP gas), and air as a general-purpose shut-off valve. Always verify that the fluid temperature remains within the -20°F to 140°F range for reliable performance.

Yes, the top actuator assembly can be rotated in 90-degree increments to accommodate specific piping layouts and clearance requirements in tight mechanical spaces.

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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.