What is the function of the check valve located at each end of the feed line of an air compressor?

The function of the check valve located at each end of the feed line of an air compressor is to keep compressor air from forcing lube oil back to the lubricator. Check valves are designed to allow flow in one direction while preventing it in the opposite direction. In the context of an air compressor, this is crucial because it helps maintain the proper lubrication of the compressor system by preventing the lube oil from flowing back into areas where it could be detrimental, such as the intake of the compressor where it might mix with the compressed air. This ensures that the compressor operates efficiently and that the lubrication system functions correctly, helping to avoid potential damage or performance issues.

Other options, while relevant to air compressor operation, do not specifically pertain to the primary role of the check valves in this particular setting.