What could be the result of improper venting of an oil tank?

Improper venting of an oil tank can lead to the creation of a vacuum within the tank. This situation arises because as oil is drawn from the tank for use, especially in heating systems, air must be allowed to enter the tank to replace the volume of oil being removed. If the venting system is inadequate or blocked, air cannot enter, and a vacuum forms. This condition can cause several issues, such as restricting the flow of oil, potentially damaging the tank due to the pressure differential, or even leading to a complete failure of the oil delivery system.

In contrast, proper venting plays a crucial role in maintaining optimal pressure and flow. It ensures that fuel can be delivered smoothly and effectively to the combustion equipment. The other options imply scenarios that are either unrelated to venting or describe ideal functioning conditions that do not result from improper venting. For example, improved combustion efficiency and stable oil pressure depend on correct venting, not the opposite.