🔍 Key Concepts

• Auxiliary boiler purpose and what it is supplying on a ship • What variable an automatic combustion control system is usually trying to keep constant • Typical control signal used to modulate or cycle burners in marine boilers

💭 Think About

• Ask yourself: in normal operation, what output from an auxiliary boiler must be kept within a narrow range to safely serve shipboard systems? • Which of these pressures would change most directly as ship steam demand rises or falls? • Which variable is most commonly used as the primary feedback signal in boiler control loops?

✅ Before You Answer

• Identify the controlled variable versus the measured but secondary variables in a boiler system • Think about which pressure directly reflects the load (demand) on the auxiliary boiler • Eliminate any option that is more of a supply condition than an output condition of the boiler.