What valve must be opened manually?

The container valve is designed to control the flow of fuel into and out of the storage container, and it typically requires manual operation for opening and closing. This ensures that personnel can assess and confirm the conditions before allowing fuel to be released or contained, which is a crucial safety measure in handling fuel-oil systems. Manual operation allows the operator to take precise control over the flow based on system requirements and safety protocols.

Unlike other valves, such as the relief valve which automatically responds to pressure changes to prevent over-pressurization, or security and pressure valves that serve specific functional roles within a system and generally do not require manual intervention, the container valve's operation is directly controlled by the operator to ensure safe handling and servicing of the fuel-oil system. This manual control is vital in maintaining safety and preventing spills or leaks during the operation.