What safety device is used to prevent backfire in an oil burner system?

The flame safeguard control is designed to ensure safe operation of an oil burner system by preventing conditions that could lead to a backfire. It continuously monitors the presence of a flame during the burner operation. If the burner fails to light correctly or if the flame goes out unexpectedly, the flame safeguard control will shut down the burner and prevent oil from continuing to flow. This function is critical because it mitigates the risk of unburned oil accumulating within the combustion chamber, which could ignite explosively if a flame is introduced later, leading to a backfire situation.

While the other options play important roles in the overall operation and safety of the oil burner system, they do not specifically address the prevention of backfire. A pressure relief valve is designed to release excess pressure, a thermostat regulates temperature, and an oil filter removes impurities from the fuel. None of these devices have the direct function of monitoring flame presence or controlling burner operation to specifically prevent backfire, as the flame safeguard control does.