Final answer:
The pressure relief valve prevents bursting and contamination of fuel in a Type III hydrant system.
Step-by-step explanation:
The filter separator control valve function that prevents the elements from bursting and allowing contaminated fuel downstream in a Type III hydrant system is the pressure relief valve.
The pressure relief valve is designed to relieve excessive pressure in the system and protect it from bursting. It opens when the pressure reaches a preset limit and allows the excess pressure to escape, ensuring the safety of the system and preventing the contamination of fuel downstream.
For example, if there is a sudden increase in pressure due to a malfunction or other factors, the pressure relief valve will open and release the excess pressure, preventing any negative consequences.