Opener will not run; display shows F5 immediately on power-up.

Safety first: Disconnect power before opening the operator cover. Do not force the door if the mechanism is jammed.

• 1. Allow motor to cool: If the opener has been used repeatedly, leave power off for 20–30 minutes to allow the internal thermal protector to reset. Restore power and test.
• 2. Check for mechanical jams: With power off, remove the cover of the Linear opener. Inspect the chain/belt or screw drive, sprockets, and trolley for broken parts or obstructions. Clear any debris and ensure the trolley moves freely on the rail.
• 3. Test door manually: Disconnect the door and move it by hand to ensure the door is not causing overload. A heavy or binding door must be repaired before using the opener.
• 4. Inspect motor wiring: Look for burnt smell, discoloration, or melted insulation at the motor leads and control board connectors. If present, the motor or board may be damaged.
• 5. Restore power and test: If no mechanical issues are found and the motor is cool, reconnect power and try a cycle. If F5 returns immediately, the motor assembly or thermal protector is likely defective and should be replaced as a unit.