What safety device is used to prevent pressure from exceeding safe levels in a boiler?

A pressure relief valve is designed specifically to prevent pressure from exceeding safe levels within a boiler system. It automatically opens whenever the pressure climbs above a pre-set limit, allowing steam or fluids to escape safely and thereby reducing excessive pressure. This action is crucial because high pressure can lead to dangerous conditions, including the risk of boiler explosions or equipment failure.

In contrast, a pressure gauge simply measures the pressure within the system, providing information rather than controlling it. A water level indicator shows the level of water inside the boiler, which is important for maintenance and operation but does not directly manage pressure. A safety switch may serve various functions, including shutting down the system under certain conditions, but it does not specifically address pressure control like a pressure relief valve does. Thus, the pressure relief valve is the primary safety device for managing pressure in boilers.