A defective oil cut-off valve can lead to which issue?

A defective oil cut-off valve can lead to after-drip, which is a situation where residual oil in the burner continues to leak out and drip after the burner has been shut off. This occurs because the cut-off valve is responsible for stopping the flow of oil when the burner is not in operation. If the valve is faulty and does not fully close, it allows oil to leak into the combustion area, leading to continued flow even when the burner is intended to be off. This can result in unburned oil pooling and dripping, which can potentially create hazards such as fire risks or equipment damage.

While fuel leakage can be an associated consequence of a malfunctioning valve, after-drip specifically refers to the oil that drips after the burner has been turned off, making it a more accurate answer in this case. Combustion issues or steam generation may occur due to other system problems, but they are not directly the result of a defective cut-off valve in the same way that after-drip is.