Opener chain or belt is slapping the rail or sagging excessively.

Safety first: Unplug the opener before adjusting chain or belt tension.

• 1. Locate tension adjustment: On the Linear rail, find the tension bolt and nut near the trolley or header end.
• 2. Adjust tension: Tighten the nut until the chain or belt has only slight sag (about 1/4 inch) at mid-span. Do not overtighten.
• 3. Inspect for damage: Look for kinked chain links or cracked belt sections. Replace if damaged.
• 4. Check sprocket alignment: Ensure the motor sprocket and rail sprocket are in line to prevent side wear.