What must be obtained if a thermally operated valve larger than 1/2" is used?

When using a thermally operated valve larger than 1/2", it is necessary to obtain the written approval of a board inspector. This requirement is in place to ensure that the installation meets safety standards and regulations set forth by building codes and other governing bodies. The board inspector's approval serves as a verification step to confirm that the valve is compliant with the Maine Fuel Code and is safe for operation.

The involvement of a board inspector ensures that any specific nuances related to the installation and function of the thermally operated valve are thoroughly evaluated. This is particularly important with larger valves, as they may have more significant implications for system efficiency, safety, and performance. By acquiring written approval, you are not only adhering to legal requirements but also promoting safe practices in fuel installation.

In contrast, the other options may not directly align with the specific regulatory requirements regarding the installation of thermally operated valves, as approval is inherently tied to formal inspections and safety regulations rather than general permissions or certifications.