Upon arrival the technician went over the system top to bottom to find any reason why the system would shut off in the middle of the day. The technician was unable to determine any reason why the system was shut off and heat of the Day. The customer stated that his nest thermostat had an eco feature, this feature would since if anybody was home, And if it had nobody that crosses sensors within an hour it was shut off and called the temperature at 76. But the customer was noticing that it was keeping it at 80° constantly. The technician recommended switching off Eco mode for now and testing to see if this solves the issue.