New York Low Pressure Boiler Certificate of Fitness (COF) Practice Test 2026 - Free COF Practice Questions and Study Guide

During the shutdown of a boiler, prioritizing the proper closure of all valves is critical for several reasons. Closing valves carefully ensures that the system is securely isolated from potential hazards, such as the release of steam or pressure that could pose safety risks to personnel and equipment. It also prevents any unintended fluid flow that could cause leaks or damage to the system or surrounding areas once the boiler is no longer operational.

Additionally, properly closed valves contribute to the integrity of the boiler system, maintaining its condition until it is ready to be used again. This practice is essential to prevent accidental re-pressurization or the mixing of incompatible fluids that could lead to operational issues or safety infractions.

In contrast, a rapid cooldown could lead to thermal shock and damage to boiler components, while quick discharge of steam might not be safe or appropriate depending on the current conditions. Lastly, while documentation is important, it is a secondary task that follows safety procedures during shutdown. Prioritizing valve closure directly relates to maintaining safety and operational integrity, which is why it is the correct answer.