Guardian opener beeps but does not move door when command is given (battery backup model, AC power lost).

Safety first: Do not repeatedly attempt to run the opener on a dead battery; it can over-discharge and damage the battery.

• Check AC power: Restore normal AC power if possible; the opener may be indicating low battery.
• Inspect battery connection: With power off, open the battery compartment and ensure the harness is firmly connected.
• Replace battery: If the battery is older than 3–5 years or measures low voltage, replace it with a Guardian-approved backup battery.
• Test after charging: Allow several hours of charging, then test operation on battery by briefly unplugging AC.