Went for an out on a system, did notice unit is not sized properly with an4 on coil and 3 ton condenser unit. Did check charge in system and is low on refrigerant. Temp split was off for system and didn’t meet specifications. Inspected evaporator coil and does have rust around it. Secondary heat exchanger and blower is dirty as well. System lacks of airflow going into the system. Hence for wear and tear on coil throughout the years. Did have a supervisor come out and will have solutions for customer with all options presented.