LiftMaster 3840 3840 Manual - Page 31
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HAVING A PROBLEM? 1. My door will not close and the light bulbs blink on my motor unit: The safety reversing sensor must be connected and aligned correctly before the garage door opener will move in the down direction. • Verify the safety sensors are properly installed, aligned and free of any obstructions. Refer to Installation Step 4: Install The Protector System®. • Check diagnostic LED for flashes on the motor unit then refer to the Diagnostic Chart on the following page. 2. My remotes will not activate the door: • Verify your Smart Control Panel® is not blinking. If it is blinking, deactivate the Lock Mode following the instructions for Using the Smart Control Panel®. • Reprogram remotes following the programming instructions. Refer to Programming. • If remote will still not activate your door, check diagnostic LED for flashes on motor unit then refer to Diagnostic Chart on the following page. 3. My door reverses for no apparent reason: Repeat safety reverse test after adjustments to force or travel limits. The need for occasional adjustment for the force and limit settings is normal. Weather conditions in particular can affect door travel. • Manually check door for balance or any binding problems. • Refer to Adjustment Step 2, Setting the Force. 4. My door reverses for no apparent reason after fully closing and touching the floor: Repeat safety reverse test after adjustments to force or travel limits. The need for occasional adjustment for the force and limit settings is normal. Weather conditions in particular can affect door travel. • Refer to Adjustment Step 1, Program the Travel Limits. 5. My lights will not turn off when door is open: • The garage door opener is equipped with a security light feature. This feature activates the light on when the safety sensor beam has been obstructed. Refer to Operation section; Using the Wall Mounted Door Control, Light Feature. 6. If battery status LED is not lit properly: • Check battery connections. Safety Reversing Sensor Sending Eye Safety Reversing Sensor (Amber Indicator Light) Diagnostics Located On Motor Unit "Learn" Button LED or Diagnostic LED "Learn" Button Receiving Eye Safety Reversing Sensor (Green Indicator Light) 31