Functions of a LiftMaster Logic 5 Control Board - DDM Garage Doors Blog

Posted September 11th, 2020 at 2:09 pm by Dan Musick

Four-wire motors

When I first got into the door business, the most common wiring for a 110-volt circuit consisted of a four-wire motor and two power leads. The two power leads ran straight to the motor. The other wires from the motor could go to either power lead. Switching these two wires would change the direction of the motor, allowing the motor to open and close a door. The new operators no longer require this type of function since they contain a LiftMaster Logic 5 control board.

A wiring diagram representing how the reversal of two wires changes the direction of the motor, pertaining to the LiftMaster Logic 5 control board.
A relay reverses two of the wires to change the direction of the motor.

The development of these systems occurred over a hundred years ago. Now, commercial operators use circuit boards to reverse motor direction and to provide a host of functions to better serve the customer. We provide the details of these functions in our new video pertaining to the LiftMaster Logic 5 control board.

The LiftMaster Logic 5 Control Board

The LiftMaster Logic 5 control board is powered by a 15-volt current supplied through a transformer in the operator. The control board outputs a 5-volt current to power the photo eyes and RPM sensor, as well as to signal the opening and closing of the door.

A few basic settings

The switch at the center of the control board allows the user to switch between the different settings of the operator.

The switch at the center of a LiftMaster control board
The switch at the center of the control board
  • B2 has three commands: open the door, stop the door from moving, and close the door
  • C2 is similar to B2. The main difference is that the door will not close unless you hold the button down.
  • T stands for timer. While using this setting, you can set the opener to close automatically a set time after opening.

A more detailed description of the different LiftMaster Logic 5 settings can be found in the owner’s manual.

This entry was filed under News. You can follow any responses to this entry through the RSS 2.0 feed.

Comments are closed.

Unmatched Support. The Right Part. DIY with Confidence!


Huge inventory of parts and torsion springs for same or next day shipping! Here you will find all you need in the most common sizes of 1 3/4," 2," 2 1/4," and 2 5/8" inside diameter springs. Please contact us for specialty springs such as TorqueMaster, EZ Set, self-Storage, and steel rolling door springs as many of these have been subject to supply chain shortages. Larger 3 3/4" and 6" inside diameter commercial and industrial springs may require a day or two to ship.

COVID update. No mask, no service! When picking up parts please wear a mask. We'll gladly provide one. Please honor the six foot social distancing rule. Thank you for your patience and understanding.

Shipping times and costs have changed. Normal transit times are currently not guaranteed, even on next day and second day shipments. Shipping prices on items over eight feet have more than tripled.