Question 83Steam Plants - Assistant Engineer

The correct answer is A) the boiler requiring excessive amounts of oxygen scavenging chemicals. A malfunction in the DC (direct-contact) heater is indicated by the boiler requiring excessive amounts of oxygen scavenging chemicals. This is because a DC heater malfunction can lead to increased oxygen levels in the boiler feedwater, which would require more chemicals to remove the excess oxygen and prevent corrosion. The other options are incorrect because they do not directly indicate a DC heater malfunction. Condensate coming in contact with steam (B), water and steam entering at different temperatures (C), and air flowing from the vent (D) may be symptoms of other boiler system issues, but they do not specifically point to a DC heater problem.