What is the function of the limit control on an oil-fired furnace?

The function of the limit control on an oil-fired furnace is primarily to prevent overheating by shutting off the burner when the temperature exceeds a preset limit. This safety mechanism is crucial because it protects both the furnace and the surrounding environment from potential damage caused by excessive heat.

When the furnace operates, the limit control continuously monitors the temperature within the system. If it detects that the temperature has risen beyond the safety threshold, it will interrupt the power to the burner, halting the combustion process. This action not only safeguards the components of the system from damage but also reduces the risk of hazards, such as fire or structural damage.

While other options might relate to various functions within a heating system, they do not specifically address the critical safety role that a limit control plays in managing the furnace's operational temperature. Therefore, this safety feature is essential for maintaining safe operation in an oil-fired heating system.