Where in an oil pump discharge line shall a relief valve be installed?

In an oil pump discharge line, a relief valve should be installed between the pump and the first shut-off valve. This position is crucial for several reasons.

Firstly, placing the relief valve between the pump and the shut-off valve ensures that it can effectively relieve excess pressure generated by the pump. If pressure builds up too high in the system, the relief valve will open, allowing the fluid to escape safely, thus protecting the pump and other components from damage.

Secondly, situating the relief valve in this location allows for immediate pressure regulation, which is important for maintaining the safe operation of the burner system. If the valve were installed after the shut-off valve, it would not respond to the pressure fluctuations generated by the pump while it is operating, potentially allowing dangerous pressure levels to reach the burner itself.

While each of the other options may seem to incorporate safety measures, they do not provide the same level of direct protection for the pump and system under operational conditions. Therefore, the correct positioning of the relief valve is essential for the overall safety and efficiency of oil burner systems.