What type of systems commonly employ check valves?

Check valves are essential components in various systems, particularly in refrigeration and air conditioning systems. Their primary function is to allow fluid or gas to flow in one direction while preventing backflow. In refrigeration and air conditioning applications, check valves help maintain the correct flow of refrigerant through the system, ensuring that it circulates effectively and prevents any reverse flow that could disrupt the system's operation. By providing this one-way flow, check valves help to maintain system efficiency, protect components from potential damage caused by back pressure, and facilitate optimal performance of the refrigeration cycle.

In contrast, while check valves can be found in heating, solar heating, and solid waste systems, their most characteristic and critical use is within refrigeration and air conditioning systems, where maintaining a specific directional flow of refrigerant is critical to the operation and efficiency of the entire system.