What is required for an oil supply line located more than 4 feet above a burner?

In systems where the oil supply line is located more than 4 feet above the burner, it is essential to have specific safety devices to ensure proper function and prevent potential hazards. A required device in such setups is a valve that can prevent overpressure or release pressure safely. The OSV (oil safety valve) or PRV (pressure relief valve) is critical in protecting the system.

When an oil line is positioned significantly above the burner, the pressure generated can exceed safe limits, especially if a blockage occurs or if there is a malfunction. The OSV or PRV functions as a safety mechanism that activates to release any excess pressure, helping to maintain safe operating conditions and protect both the equipment and the surrounding environment.

In this context, other options do not fulfill the necessary safety requirements for an oil supply system operating under the specified conditions. Therefore, utilizing an OSV or PRV valve is a critical aspect of the setup for an oil supply line at such a height.