Maxitrol M620B-1 Modulating Gas Valve with Low Fire Adjustment HVAC Control Valves & Actuators - 1

The Maxitrol M620B-1 is a 1-inch modulating gas valve designed exclusively for direct-fired negative pressure (pull-through) burner applications. This valve is part of Maxitrol's Selectra series and provides precise, non-fluctuating, instantaneous temperature control without requiring a motor or mechanically driven butterfly valve.

Key Features:

• 1-inch NPT pipe size for optimal flow capacity
• Low fire adjustment accessible from both sides for convenient field setup
• Integrated bypass orifice for smooth modulation throughout the firing range
• Counter spring design keeps valve closed under negative pressure conditions
• Provides infinite, continuous flame adjustment for precise temperature control
• Maximum outlet pressure of 7.0" w.c. (water column)
• Maximum current draw of 0.5 amps
• Requires separate upstream gas pressure regulator (M valve configuration)

Applications:

• Direct-fired burners in negative pressure environments
• Makeup air systems
• HVAC applications requiring precise temperature control
• Industrial heating processes
• Baking and drying applications requiring consistent temperatures

Technical Specifications:

• Compatible with natural gas, manufactured gas, mixed gas, liquefied petroleum, and LP gas-air mixtures
• Static pressure rating: 5.0 psi
• Operating temperature range: -40°F to 125°F
• Voltage increase corresponds to outlet pressure increase for proportional control
• Must be mounted in upright position in horizontal pipe run, downstream of other controls

The M620B-1 valve operates by applying voltage to the control's solenoid, which creates a magnetic force on the plunger. This force pushes down on the main diaphragm, similar to the spring loading of a gas pressure regulator. When the force overcomes the counter spring, the main valve opens and allows modulated gas flow in addition to bypass flow. This unique design delivers smooth, responsive flame modulation for applications demanding precise temperature control.

Designed for use with Maxitrol Selectra series modulation systems including Series 14, 24, 44, 94, and SC11 signal conditioners. The SC11 can convert computer or PLC controller signals when standard Maxitrol companion controls are not specified.