Opener runs briefly then stops and reverses; door may move a few inches and return to open; diagnostic LED flashes three times repeatedly.

Safety first: Disconnect power before adjusting mechanical components. Keep hands and tools clear of the door path while testing.

Steps to correct travel and force:

• 1. Check door balance: Pull the emergency release cord to disconnect the Stanley opener from the door. Manually lift the door halfway and release. A properly balanced door should stay in place. If it falls or shoots up, have a professional adjust the torsion or extension springs before proceeding.
• 2. Inspect tracks and rollers: Look for bent vertical or horizontal tracks, flat-spotted rollers, or debris in the track. Clean the tracks with a dry cloth and lightly lubricate the roller bearings with garage door lubricant (not grease).
• 3. Reconnect opener: Re-engage the trolley to the opener carriage by running the opener until it clicks back into the release latch, or manually push the trolley until it locks.
• 4. Adjust down travel limit: On most Stanley openers, locate the DOWN LIMIT adjustment screw or dial on the side or rear of the motor head. Turn it slightly in the direction indicated to increase travel (usually clockwise). Make small adjustments (1/4 turn) and test.
• 5. Adjust down force: Locate the DOWN FORCE control. Increase it slightly (1/8–1/4 turn) to allow the opener to push through normal resistance, but do not over-increase; the door must still reverse when it hits an obstruction.
• 6. Test safety reversal: Place a 2x4 board flat on the floor under the door. Close the door with the opener. It should contact the board and reverse within 2 seconds. If not, reduce force and call a technician.