Who conducts the boiler flex testing?

The correct choice is the automatic boiler control technician, as they are specifically trained to conduct tests relating to the boiler's control systems and ensure they function properly under varying conditions. This includes performing tests that involve different operational settings to verify that all automatic controls respond correctly and safely during operating scenarios.

Automatic boiler control technicians have expertise in the various automation systems that manage the boiler's operation, such as maintaining pressure and temperature controls, as well as ensuring safety measures are in place. Their role is critical in confirming that the boiler operates efficiently and effectively, especially during flex testing, where the system's responses are evaluated under changing operational parameters.

While other job titles, such as boiler maintenance technicians, steam engineers, and supervising engineers, play important roles in the overall maintenance and operation of boilers, their focus is typically on broader maintenance tasks, engineering principles, or oversight functions rather than specifically on the testing of control systems.