Which fitting is considered the most important on a boiler?

The safety valve is considered the most important fitting on a boiler due to its critical role in maintaining safe operating conditions. Its primary function is to prevent excessive pressure buildup within the boiler, which could lead to catastrophic failures, such as explosions or ruptures. When the boiler pressure exceeds a predetermined limit, the safety valve automatically opens, allowing steam to escape and reducing pressure back to a safe level. This automatic response safeguards both the boiler and personnel operating it.

In this context, the safety valve's importance is underscored by its direct impact on safety in boiler operations. No other fitting has the same level of responsibility for preventing dangerous situations caused by pressure violations, making it a crucial component in boiler design and operation. The other fittings, while important for their respective functions—like regulating water supply with the feed valve or allowing for system maintenance via the blow-off valve—do not possess the same level of importance in terms of immediate safety risks as the safety valve does.