Abstract: Condensation line purging devices and assemblies. The present invention relates to devices and assemblies for purging HVAC condensation lines. Such lines are relatively delicate, as opposed, for instance, to drain lines and plumbing systems. Accordingly, devices of the present invention include a body which is adapted to contain a conventional gas cylinder such as a 12 gram CO.sub.2 cylinder. The body is adapted to connect to a nozzle which in turn is connected to a connector that is attached to the condensation line. The body may be rotated onto the nozzle in a manner that controllably releases gas pressure from the gas cylinder into the condensation line so as to cause a pressure buildup that effectively purges the condensation line without breaching its seals or other discontinuities. Such control may occur by virtue of the shape of a pin protruding from the interior portion of the nozzle and adapted to penetrate the gas cylinder.