While water softener technology is the same for a house as it is for a large hospital, for example, a large disparity in volume requirements makes the design, installation, planning and service more complicated for a commercial water softener.
When sizing a water softening system for this application, doing the math and getting reasonably accurate volume demand information in gallons is critical to determining the size of the commercial water softener or softeners. Water softening resin has a finite amount of water that it can soften before it needs to go into a backwash (or self cleaning) cycle to clean the resin beads for continued softening. Additionally, determining the size of the brine tank for softener salt storage is also very important to keep the tank filling requirements at a reasonable level for the personnel maintaining this.
Space available for the equipment is another important consideration. To avoid a long piping run to and from the system, a good location needs to be selected. Additionally, any space restrictions will need to taken into consideration when sizing both the softener and brine tank sizes.
WHEN ARE TWO COMMERCIAL WATER SOFTENERS NEEDED?
In a hospital setting or other setting where water is being used essentially 24 hours per day, a back up softener may be required. The main reason for this is when one softener goes into its backwash cycle, the second softener will be able to provide a steady supply of softened water to the facility. Without this backup, unconditioned water will be pulled through the system while the softener is in the backwash cycle. In the photo at the top of the page, this system is feeding make-up water to the boiler. It has to be clean water 24 hours a day.
For more on water softening and how it works, see the link at Water Softening.