Which of the following indicates a possible issue in the oil delivery system?

A decrease in system pressure can indicate a problem in the oil delivery system. In an oil heating system, proper pressure is essential for maintaining the flow of oil from the tank to the burner. When there is a drop in pressure, it can suggest potential issues such as blockages, leaks, or a failing oil pump. These issues can compromise the effectiveness of the heating system and may lead to inadequate fuel delivery to the burner, resulting in reduced efficiency or even system failure.

Stable system vacuum, consistent burner operation, and increased boiler efficiency generally signify that the system is functioning properly. A stable vacuum suggests good system integrity without leaks, while consistent burner operation indicates that the burner is performing reliably. Increased boiler efficiency is a sign of optimal operation, meaning that the system is delivering and utilizing oil effectively. In contrast, a decrease in system pressure is a clear warning sign that something may be amiss within the delivery system, necessitating attention and possible remediation.