Furnace clean and tune. Cycled system. Checked heat exchanger. Found rust in the front and on the first bend of primary heat exchanger. This is common with burner damage and corrosion. Checked, removed, and cleaned burners and flame sensor. Cleaned burners as best I could. They are now in working order. Checked and cleaned flame sensor. Found that flame sensor is chipped. This will cause flame sensor failure in future. Ventor motor bearings are also worn and noisy. This motor will seize at any time. Rust throughout the system. Found water leaking from Ventor motor gasket and also a cracked transition assembly. Water rust spots also found in blower compartment. Igniter is worn and replacement is recommended. System is 13 years old and there are several issues throughout the unit. Due to age, condition, and cost of repair, second opinion is recommended. Future failure is expected. Job complete.