Liftmaster 71-MLSBC Field Modification, Logic SBC

Single-Button Control Upgrade for Medium-Duty Logic Operators

The LiftMaster 71-MLSBC Field Modification Kit enhances Medium-Duty Logic (MDL) door operators by providing a single-button control solution. This kit modifies the input functionality, allowing a single control input to function as both Open and Close depending on the door’s position. If the operator is at the open limit, the input acts as a Close command. At all other times, it functions as an Open command. For safety and proper functionality, this kit must be used in conjunction with a wall control that has a stop button.

Key Features

• Provides single-button control for Open and Close functions
• Adaptive input changes based on the door’s position
• Compatible with Medium-Duty Logic operators
• Integrates with external radio receivers for wireless operation
• Requires a stop button wall control for safe use
• Includes limit switch, terminal block, mounting brackets, and wiring components

Technical Specifications

• Manufacturer: LiftMaster®
• Part Number: 71-MLSBC
• Compatibility: Medium-Duty Logic (MDL) door operators
• Input Function: Close command when at the open limit, Open command at all other times
• Required Components: Must be used with a wall control featuring a stop button
• Installation Requirements: Disconnect power before installation, mount auxiliary limit switch to the existing Open Limit switch, secure the terminal block inside the electrical box, connect provided wires to the logic board terminals, replace cover, and restore power

Conclusion

The LiftMaster 71-MLSBC Field Modification Kit is a necessary upgrade for Medium-Duty Logic door operators requiring single-button control with external radio receivers. By automatically switching between Open and Close functions based on the door’s position, this kit ensures smooth operation while maintaining compatibility with LiftMaster MDL systems. Before purchasing, review the installation manual and confirm compatibility with your operator.