What type of valve must steam boilers be equipped with at the bottom?

Steam boilers must be equipped with a blowoff valve at the bottom to safely remove sediment and impurities that accumulate in the boiler. This valve is essential for maintaining water quality and ensuring the efficient operation of the boiler. By allowing operators to periodically flush the boiler, the blowoff valve helps prevent scale buildup, which can lead to overheating and damage to the boiler structure.

The blowoff valve is specifically designed to discharge water from the boiler effectively, so it's crucial for the maintenance of steam boilers. Regular blowoff is part of the operational protocol to extend the life of the system and improve its efficiency. This operational importance makes the blowoff valve a required safety feature according to mechanical codes.

In contrast, while relief valves protect against excessive pressure and drain valves are used for routine maintenance or emptying systems, they do not serve the same purpose as a blowoff valve in relation to sediment removal. Check valves are primarily used in systems to prevent backflow and are not directly relevant to the operation or maintenance of steam boilers in this context.