What is required for a boiler connected in battery when there is a manhole opening?

In a battery of boilers, particularly when there is a manhole opening, having a free blowing drain is crucial for ensuring safety and operational efficiency. The term "free blowing drain" refers to a drain that allows for the unrestricted release of steam or water from the boiler system, which is essential for managing excess pressure and ensuring that any water or contaminants can be effectively removed from the system.

The presence of a manhole opening means there is access for maintenance and inspection, increasing the risk of pressure and water buildup. A free blowing drain allows operators to promptly and effectively manage these conditions, avoiding potential hazards such as pressure build-up or contamination. This is vital for safe operations, especially in a system where multiple boilers may be interconnected, as improper drainage can lead to severe consequences.

Other options, while relevant in specific contexts, do not directly address the need for proper drainage in relation to a manhole opening when managing a battery of boilers. For example, a separate feed pump is typically required for maintaining water levels, dedicated safety valves ensure overpressure protection for individual units, and pressure relief valves function to allow for controlled release but do not specifically facilitate drainage. Thus, the choice of a free blowing drain is the most appropriate to fulfill the requirements for safety and operational