Red LED is constant and the beep sounds every 30 seconds. The manual says to call for service. The door works fine. What is the problem and why is it necessary to call for service?

It sounds like the battery system is not working. How old is the battery, they do eventually, just quit working, and require battery replacement. Extract and test the battery. try an external (different) charger.

If you have an opener with battery backup this may help. BBU stands for 'battery back up.'

This is battery related. On top of your unit is a battery pack with three colored led lights. You can tell what is going on by looking at these. This information is in your manual or here it is.
GREEN LED: All systems are normal. A solid LED light indicates the batteries are fully charged. A flashing LED indicates the batteries are being charged. NOTE: Batteries do not have to be fully charged to operate the motor unit. YELLOW LED: The motor unit has lost power and is operating off of the BBU. A solid LED with beep, sounding approximately every 2 seconds, indicates the motor unit is activating the door and is operating off of the BBU. A flashing LED with beep, sounding every 30 seconds, indicates batteries are low. Once the power is restored the BBU will recharge. This is indicated by a flashing GREEN LED. RED LED: An error has been detected and the BBU will automatically shut off. The BBU will attempt to restart by reconnecting to the batteries. If the error is still present it will shut itself off again. This process will repeat every 5 minutes or until the error has been resolved. This is used to prevent further draining of the batteries. If a red LED remains on when the power is restored, and is accompanied by a beep sounding every 30 seconds, please call for service.

Here is some general information that you probably already have. The opener should keep that battery charged. I would recommend getting a service technician out. Just when you really need that battery backup it will be out.

On top of your unit is a battery pack with three colored led lights. You can tell what is going on by looking at these. This information is in your manual or here it is. GREEN LED: All systems are normal. A solid LED light indicates the batteries are fully charged. A flashing LED indicates the batteries are being charged. NOTE: Batteries do not have to be fully charged to operate the motor unit. YELLOW LED: The motor unit has lost power and is operating off of the BBU. A solid LED with beep, sounding approximately every 2 seconds, indicates the motor unit is activating the door and is operating off of the BBU. A flashing LED with beep, sounding every 30 seconds, indicates batteries are low. Once the power is restored the BBU will recharge. This is indicated by a flashing GREEN LED. RED LED: An error has been detected and the BBU will automatically shut off. The BBU will attempt to restart by reconnecting to the batteries. If the error is still present it will shut itself off again. This process will repeat every 5 minutes or until the error has been resolved. This is used to prevent further draining of the batteries. If a red LED remains on when the power is restored, and is accompanied by a beep sounding every 30 seconds, please call for service.

On the back of the garage door opener there is a red button. Depress this button and sync your keypad to the opener. This will re-establish the code and reset the remote.

This is battery related. On top of your unit is a battery pack with three colored led lights. You can tell what is going on by looking at these. This information is in your manual or here it is.
GREEN LED: All systems are normal. A solid LED light indicates the batteries are fully charged. A flashing LED indicates the batteries are being charged. NOTE: Batteries do not have to be fully charged to operate the motor unit. YELLOW LED: The motor unit has lost power and is operating off of the BBU. A solid LED with beep, sounding approximately every 2 seconds, indicates the motor unit is activating the door and is operating off of the BBU. A flashing LED with beep, sounding every 30 seconds, indicates batteries are low. Once the power is restored the BBU will recharge. This is indicated by a flashing green LED. RED LED: An error has been detected and the BBU will automatically shut off. The BBU will attempt to restart by reconnecting to the batteries. If the error is still present it will shut itself off again. This process will repeat every 5 minutes or until the error has been resolved. This is used to prevent further draining of the batteries. If a red LED remains on when the power is restored, and is accompanied by a beep sounding every 30 seconds, please call for service.

This is battery related. On top of your unit is a battery pack with three colored led lights. You can tell what is going on by looking at these. This information is in your manual or here it is.
GREEN LED: All systems are normal. A solid LED light indicates the batteries are fully charged. A flashing LED indicates the batteries are being charged. NOTE: Batteries do not have to be fully charged to operate the motor unit. YELLOW LED: The motor unit has lost power and is operating off of the BBU. A solid LED with beep, sounding approximately every 2 seconds, indicates the motor unit is activating the door and is operating off of the BBU. A flashing LED with beep, sounding every 30 seconds, indicates batteries are low. Once the power is restored the BBU will recharge. This is indicated by a flashing green LED. RED LED: An error has been detected and the BBU will automatically shut off. The BBU will attempt to restart by reconnecting to the batteries. If the error is still present it will shut itself off again. This process will repeat every 5 minutes or until the error has been resolved. This is used to prevent further draining of the batteries. If a red LED remains on when the power is restored, and is accompanied by a beep sounding every 30 seconds, please call for service.

This is battery related. On top of your unit is a battery pack with three colored led lights. You can tell what is going on by looking at these. This information is in your manual or here it is.
GREEN LED: All systems are normal. A solid LED light indicates the batteries are fully charged. A flashing LED indicates the batteries are being charged. NOTE: Batteries do not have to be fully charged to operate the motor unit. YELLOW LED: The motor unit has lost power and is operating off of the BBU. A solid LED with beep, sounding approximately every 2 seconds, indicates the motor unit is activating the door and is operating off of the BBU. A flashing LED with beep, sounding every 30 seconds, indicates batteries are low. Once the power is restored the BBU will recharge. This is indicated by a flashing green LED. RED LED: An error has been detected and the BBU will automatically shut off. The BBU will attempt to restart by reconnecting to the batteries. If the error is still present it will shut itself off again. This process will repeat every 5 minutes or until the error has been resolved. This is used to prevent further draining of the batteries. If a red LED remains on when the power is restored, and is accompanied by a beep sounding every 30 seconds, please call for service.

The only information I can find.

RED LED: An error has been detected and the BBU will automatically shut off. The BBU will attempt to restart by reconnecting to the batteries. If the error is still present it will shut itself off again. This process will repeat every 5 minutes or until the error has been resolved. This is used to prevent further draining of the batteries. If a red LED remains on when the power is restored, and is accompanied by a beep sounding every 30 seconds, please call for service.

This is battery related. On top of your unit is a battery pack with three colored led lights. You can tell what is going on by looking at these. This information is in your manual or here it is.
GREEN LED: All systems are normal. A solid LED light indicates the batteries are fully charged. A flashing LED indicates the batteries are being charged. NOTE: Batteries do not have to be fully charged to operate the motor unit. YELLOW LED: The motor unit has lost power and is operating off of the BBU. A solid LED with beep, sounding approximately every 2 seconds, indicates the motor unit is activating the door and is operating off of the BBU. A flashing LED with beep, sounding every 30 seconds, indicates batteries are low. Once the power is restored the BBU will recharge. This is indicated by a flashing green LED. RED LED: An error has been detected and the BBU will automatically shut off. The BBU will attempt to restart by reconnecting to the batteries. If the error is still present it will shut itself off again. This process will repeat every 5 minutes or until the error has been resolved. This is used to prevent further draining of the batteries. If a red LED remains on when the power is restored, and is accompanied by a beep sounding every 30 seconds, please call for service.

My battery is bad. I knew it, but did not feel like it was worth any of my attention. The beeping started yesterday and this was worth my attention. Everyone in the family complained. I suspected it was the battery.

I unplugged the unit. Disconnected the battery. Waited for 30 seconds. Plugged it back in. It works fine and no beeping.

I suspect it is a warning to replace the battery.