These pumps are based on the T31 • T41 • T51 Series pumps. Please see those product pages and curves to make rough model selections. Note that due to the requirement for controlled leakage designed into these units for proper bearing lubrication, custom factory sizing to your specific application is necessary. These pumps have the distinct advantage of eliminating the need for a mechanical seal, by allowing a controlled leakage to pass through the bearings and back into the fluid source tank. For small chiller systems that can accept a tank mounted immersible design, the S Series represents the most cost effective sealless pump solution. Please note that the high pressure characteristic of a single stage S Series unit allows the replacement of multiple stacked stages of an equivalent immersible multi-stage centrifugal. This is extremely important where standardization of tank sizes and/or depths are necessary for OEM system cost reductions. These units are produced in a custom designed fashion for your particular fluid, performance, and immersion (or tank) depth. Please contact the factory for samples, pricing, and delivery for volume OEM customers only.