Two-way control valves differ from other types of valves used in HVAC systems, such as isolation valves and check valves, in their function and operation. While isolation valves are used to isolate sections of the system for maintenance and repair, and check valves are used to prevent backflow, two-way control valves are used to regulate the flow of fluid to the process under control. Two-way valves are typically more complex and sophisticated than other types of valves, requiring actuators and controllers to operate effectively.