Performed heating maintenance tune up service on heat pump system checking all electrical components, refrigerant balance, unit start up, operation, defrost, shutdown, treatment of drains, checking of humidifier. Customer complaint of unit appears to be running constantly in cooler temps and a noise at intermittent times while unit is running. Checked blower, blower operation, speed taps for both call for back up heat and regular call for heat. Checked blower operation during call for humidifier. Checked defrost and electric heat. Did not identify any unusual noises at this time. Believe system running extended cycles due to low outdoor temperatures at night as refrigerant balance and unit electrical components are within manufacturer's specifications. Adjusted thermostat cycles per hour setting to help address long cycle issues. Everything runs great!