LiftMaster MHS Medium-Duty Slow-Speed Commercial Door Operator is a wall-mounted door control solution designed for rolling sheet doors that require controlled, slow-speed operation in commercial environments.

This operator is recommended for small rolling sheet doors and grilles in medium-duty cycle applications where slower operating speed and a manual hoist are required. It delivers dependable performance for facilities with moderate daily usage.

The MHS series is engineered with solid-state logic control, mechanical limit settings, and emergency manual operation, making it a reliable choice for commercial and industrial door systems.

Specifications Application

• Rolling sheet doors and grilles

• Medium-duty commercial use

• Wall-mounted installation 

Rated Duty Cycle

• Up to 12 cycles per hour

• Up to 50 cycles per day

Operator Speed

• 4–5 inches per second (slow speed) 

Limit Settings

• Mechanical 

Emergency Operation

• Floor-level manual emergency release sash chain

• Automatic re-connect when tension is removed

Control & Programming

• Solid-state medium-duty logic circuit board

• Tactile programming buttons

• Programmable timer-to-close: 5–60 seconds (5-second increments) 

Controls

• 3-button wall control station

• Push-button station (Open / Close / Stop) 

Electrical & Drive

• Voltage: Single-phase 115V

• Control circuit: 24V NEC Class 2

• Drive reduction:

– First stage heavy-duty 4L V-belt

– Second and third stages #48 chain

• Bearings: Heavy-duty oil-filled bushings

• Brake: None (slow-speed operator for light sheet doors)

Construction

• NEMA 1 electrical enclosure

• Heavy-duty 11-gauge steel frame

• Baked-on powder coat finish

• All reduction sprockets drilled and pinned to shafts

Capacity

Maximum door area (approx.):

• Aluminum grilles (24-ga): up to 320 sq. ft.

• Aluminum doors (22-ga): up to 275 sq. ft.

• Steel grilles (20-ga / 18-ga): up to 200 sq. ft.

Installation Limits

• Maximum door height: 14 ft (standard)

• Maximum door width: 22 ft

• Maximum allowable square footage: 320 sq. ft.

Compliance & Safety

• Designed to meet UL 325 requirements

• Compatible with LiftMaster monitored entrapment protection devices

Warranty

• Limited warranty: 2 years

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Price available upon request. Contact us for a custom quote.