What effect does a clogged filter have on an oil burner system?

A clogged filter in an oil burner system primarily affects the flow of fuel. When the filter becomes clogged, it restricts the amount of oil that can pass through, leading to lower flow rates. This reduced flow can result in inadequate fuel delivery to the burner, which can impair combustion and lead to inefficiencies in the system.

In contrast, other effects described in the options would not occur with a clogged filter. For instance, combustion efficiency would not increase, nor would fuel atomization improve; rather, the opposite is likely true, as there would be insufficient fuel to adequately atomize and burn. Additionally, a clogged filter does not eliminate air leaks; instead, it can contribute to operational issues that could potentially exacerbate air leaks if not addressed. Thus, the primary consequence of a clogged filter is the reduced flow rates of oil to the burner, which is accurately captured in the answer provided.