Question 31Steam Plants - Assistant Engineer

The correct answer is B) prevent backflow of water from the boiler in the event of a feed pump failure. The main feed check valve is designed to prevent the backflow of water from the boiler into the feed system. This is crucial to maintain the proper water level in the boiler and prevent damage in the event of a feed pump failure. If the feed pump stops working, the check valve will close to stop hot water or steam from the boiler from flowing back into the feed system, which could potentially damage equipment or create unsafe conditions. The other answer choices are incorrect because they do not accurately describe the primary function of the main feed check valve, which is to prevent backflow from the boiler.