LiftMaster GH GH LOGIC 3 Manual - Page 23

AUTOMATICALLY LEARNED PROGRAMMING AUXILIARY REVERSAL SYSTEM / RPM SENSOR Feature: This feature utilizes the RPM sensor connected to the logic board to detect when the clutch slips and reverses the door (clutch must be properly adjusted). In addition, the RPM eliminates the need for a centrifugal switch on 1/3 and 1/2 horsepower single phase motors. Benefit: The Auxiliary Reversal System reverses the operator upon hitting an obstruction, preventing excessive door and operator damage. We require the use of safety devices for primary safety protection. By removing the centrifugal for 1/3 and 1/2 horsepower single phase motors, the leading cause of motor failures is eliminated. (Auxiliary Reversal System not applicable on models GH and GT.) NOTE: This feature is automatically learned and does not require programming. LOSE OPEN RPM Sensor Logic Board MAXIMUM RUN TIMER (MRT) Feature: The operator can learn the time it takes to open or close the door plus an additional 10 seconds. Benefit: If the operator does not meet its open or close limit within the set time it will stop, limiting damage to the door and operator. To Program: NOTE: The default setting for the MRT is 90 seconds. In the event the application requires the MRT be manually learned for a longer duration follow steps below. 1. Start with the door in the closed position. 2. Set the selector dial to "PROGRAM". 3. Press MRT button on logic board. 4. Press the OPEN button and wait for the door to reach the full open limit. 5. Once the door has reached the open position, programming is complete. 6. Turn dial to desired wiring type. NOTE: To reset MRT only, turn selector dial to program and press and hold the MRT button until the MAS led flashes rapidly. SELECTOR DIAL Operation will vary depending on wiring type 23