Which component is primarily used to protect against boiler overpressure?

The pressure relief valve is crucial for protecting a boiler against overpressure situations. It is designed to automatically open when the pressure exceeds a predetermined limit, allowing excess steam or fluid to escape safely from the system. This function helps maintain safe operating conditions and prevents potential hazards, such as equipment failure or explosions due to excessive pressure buildup.

Pressure gauges, while important for monitoring and providing information about the pressure within the boiler system, do not take action to prevent overpressure; they merely indicate the pressure level. A condenser and a feedwater heater serve different purposes, such as improving system efficiency and heat exchange, but they do not play a direct role in pressure relief and safety. The pressure relief valve's active role in maintaining pressure limits is what makes it the primary protective device in a boiler system.