I arrived into a heat pump not defrosting. During inspection I put the heat pump in test mode for defrost and it would not cycle. Replaced the defrost board when I was ready to test the generator shut down the heat pump and the electric furnace in the attic so I was unable to test. Customer is going to call the support for the Generator and get back to us when he is up and running. Returned and restarted generac system. System is heating at this time.