Chain-drive Genie opener is very noisy; chain slaps rail during operation.

Safety first: Disconnect power before adjusting chain tension. Do not overtighten the chain.

Steps:

• Inspect chain sag: At mid-span, the chain should have slight sag but not hang down significantly.
• Adjust tension: Use the chain tension nut at the trolley end to tighten the chain until sag is minimal but not rigid.
• Lubricate: Apply light garage door chain lubricant to the chain and sprockets. Wipe off excess.
• Test: Run the opener and listen for reduced noise. Re-adjust if necessary.