SMOOTH OPERATION Wall-mount design and DC motor reduce noise for quiet, powerful performance. Locate the Manual Force Adjustment dials at the back of the LiftMaster garage door opener. Model 3900 is a light-duty jackshaft operator for light-duty commercial sectional applications only. Note: The adjustment button is the rectangular button between the Up and Down arrow buttons. Intended for applications using smaller, lighter sectional commercial doors requiring 25 cycles or less per day, the LJ8900W is ideal for dock doors, small warehouses, small businesses, and outbuildings. Residential Jackshaft Opener: How to resolve issues with the RJO losing its travel limits. STORM-PROOF POWER Keeps the operator running even when the … Resolving issues with the Residential Jackshaft Operators (RJO and RJO10) travel limits, 3800, 3900, 8500, 8500W, 8500WRGD, 8500WLA, LJ8900W, LJ8950W. If the door is hard to hold or doesn't reverse, DECREASE the DOWN (close) force by turning the control counterclockwise. It features a compact design ideal for limited height, cathedral, or obstructed ceiling installations. The LJ8900W is LiftMaster's first wall-mounted commercial door operator with built-in Wi-Fi®. Optional accessories are available for the LiftMaster® LJ8900W and LJ8950W to create the best solution for each application. Elevate your sales by making their commercial door operator system even more reliable and secure. After each adjustment, run the opener through a … Before you adjust the force setting of your garage door opener, ensure your garage door tracks, jambs, and rollers are in good condition. LiftMaster 3900/LJ8900W Light Duty Commercial Jackshaft Operator $ 365.00. Make small adjustments until the door reverses normally. You might damage the motor of your garage door opener if there is a lot of resistance from the door tracks. See Adjustment Step 3, page 30 in your installation manual.