5 stars!! Roof 234 Package Unit Daikin D987 46808763: Preventative Maintenance - Quarterly -Inspect heat exchanger or heating elements. -Inspect flue system—check for proper attachment to the furnace, any dislocated sections, and for signs of corrosion. ... -Inspect control box, associated controls, wiring and connections. -Clean or replace air filters. -Inspect conditioned airflow system (ductwork)—check for leaks. Cafeteria 2 Global G4500 65402654 87321321: 1. Tighten all electrical connections in the electrical panel. 2. Check fan motors and blades. 3. Check all defrost heaters. 4. Clean the drain pan and check for proper drainage. 5. Clean the evaporator coil surface. Roof 123 Package Unit Carrier New 12345 9481741: Preventative Maintenance - Quarterly -Inspect heat exchanger or heating elements. -Inspect flue system—check for proper attachment to the furnace, any dislocated sections, and for signs of corrosion. ... -Inspect control box, associated controls, wiring and connection