While your vessel is steaming with one boiler, the automatic combustion control system sensing line for the idle boiler is accidentally opened. How will this affect the steaming boiler?

Correct Answer: Option D — The steam pressure will rise.

Opening the sensing line of an idle boiler exposes the master controller to dead or atmospheric pressure, causing the combustion control system to misinterpret the signal as a severe pressure drop, commanding maximum fuel and air, which forces the active steaming boiler pressure to rise.