My Nutone G578 garage door opener will not reverse. It only wants to go up. What do I need to repair it?

Answer 1

realign or repair photo-eyes

The problem is relatively simple , if the motor is operating properly in one dirction. The problem must be either with capacitor or with reverse current of three phase motor

Answer 2

Try to hold the wall button continually when the door is open, if the motor will close the door there is 2 things to check: sensors alignment, door balance (the door should free hang when its half opened. if didn't help, you should contact a professional garage door repair