Furnace clean and tune. Cycled system. Checked heat exchanger. Found heavy rusting and corrosion in all chambers. Burners are rusted. Flame sensor is corroded. Checked and tightened electrical connections and clamps. Found ventor motor bearings are worn. Checked venting. Preformed combustion test and found higher levels in exhaust. No CO found in airstream. Found water leaking from ventor motor. This joint is a boot seal, this is where the water is leaking. Average life expectancy for this unit is 14 years. This system is over 30 years and in poor condition. Failure is expected. Job complete. Due to age, comdion, and cost of repai, second opinion is recommended.