The Cooling Water Isolation Skid (CWIS) is an economical, practical means of maintaining on-line sample temperature where abundant, cool surface water sources exist (i.e. river, lake or dam). It is designed to allow the use of high solids or hard water supplies for cooling a process line or battery of sample coolers without concern that the solids in the raw water supply will precipitate or plate out in the process or shell of the coolers. The CWIS isolates the raw water from the process or coolers through the use of an intermediate plate heat exchanger. Waters Equipment Co. P.O. Box 576, 204 DeKalb Pike Lansdale, PA, 19446