What safety device prevents oil from flowing to the burner if ignition fails?

The safety device that prevents oil from flowing to the burner if ignition fails is the safety shut-off valve. This valve plays a crucial role in ensuring safety within oil burner systems. In the event that the burner fails to ignite, the safety shut-off valve automatically closes to stop the flow of oil. This is essential because continued oil flow without ignition could lead to serious hazards, including the risk of fire or explosion. By halting fuel delivery when there is an ignition failure, the safety shut-off valve helps to mitigate such dangers and protect both the equipment and the surrounding environment.

Other devices listed do not serve this specific function. For instance, a pressure relief valve is designed to release excess pressure within a system, protecting it from damage due to over-pressurization, rather than controlling fuel flow based on ignition status. An automatic ignition system facilitates the ignition process itself but does not directly prevent oil flow upon failure. Finally, a flow control valve regulates the amount of oil that reaches the burner but does not have the safety function tied to ignition failure. Thus, the safety shut-off valve is the critical component designed specifically for safeguarding against the consequences of ignition failures in oil burners.