Question 472Steam Plants - Assistant Engineer

The correct answer is D) automatically regulates the quantity of oil and air flow to the burner. The pressuretrol is a safety device installed on an auxiliary boiler that senses changes in steam pressure. When the steam pressure increases, the pressuretrol automatically reduces the quantity of oil and air flowing to the burner, thereby regulating the combustion process and preventing a dangerous increase in steam pressure. This automatic regulation of the fuel and air flow is the primary function of the pressuretrol. The other answer choices are incorrect because they do not accurately describe the main purpose of the pressuretrol. The pressuretrol does not control the flow of feed water (A), monitor the boiler's high water level (B), or secure the fires when a fusible plug burns out (C).