High-side piping can be simply described as the piping that connects various components of a refrigeration system that operate at, or near, the system condensing temperature. This includes, but is not limited to, condensers, receivers, thermosyphon oil coolers, purgers, and oil separators.
Twenty years ago, high-side piping was just “condenser piping,” although the necessity to purge noncondensibles was well understood. How it was to be accomplished was not very clear.