Had a power outage this morning Generator came on like it was supposed to but the transfer switch did not move to cut off utility and go to standby power. Both generator and transfer switch has operated as is supposed to ever sense installation about 4 years ago. This is the first time this has ever happened. I moved switch manually to get standby power and then manually back to utility when power came back on.. I tested it again and it did not transfer then either. Does anyone know what I should check. I can not find my installation nor owners manuals so I don't have a trouble shooting guide.