At what pressure should drum vents be closed when putting a boiler into service?

The correct pressure at which drum vents should be closed when putting a boiler into service is 170 kPa. This pressure is significant because it represents a safe operational level that helps ensure the integrity of the boiler system when it transitions from a cold to a hot state. Closing the vents at this pressure helps to prevent the escape of steam and maintains the safety and efficiency of the boiler during startup.

Typically, during the process of bringing a boiler online, specific guidelines and standards are followed to maintain safety and efficiency. The choice of 170 kPa reflects these standards, as it signifies a point where the boiler can handle the increasing pressure without risk of damage or operational issues.

Maintaining the correct pressure is vital for the safety of the system and personnel. Closing the vents too early or at a lower pressure could lead to a potential buildup of unsafe conditions, while waiting too long could create operational inefficiencies. It's important during pre-service checks to ensure that all parameters align with industry standards to provide a reliable service.