Which of the following is a common cause of ignition failure in an oil burner?

In the context of oil burners, ignition failure often stems from an inadequate fuel supply. When the oil burner does not receive enough fuel, it can't achieve the proper mixture of fuel and air required for combustion. This deficiency can occur due to several reasons, such as a clogged fuel filter, blocked fuel lines, a malfunctioning fuel pump, or problems with the oil storage tank. These issues can significantly hinder the burner’s ability to ignite, leading to operational failures.

The other factors, such as low ambient temperature or excessive air, might influence combustion efficiency or overall performance, but it is the lack of sufficient fuel that most directly leads to ignition problems in an oil burner system. A properly functioning transformer plays a crucial role in creating the spark necessary for ignition but does not contribute to ignition failure in a direct manner related to fuel supply.