Undercounter dishwashers are typically geared for smaller operations with low volume. These machines are sized to handle between 21 and 55 racks per hour.

Low-temp warewashers utilize water that is at 120 degrees F, while also incorporating chemicals for proper sanitizing. With high-temp warewashers, water is heated to 150 degrees F for washing and 180 degrees F for sanitizing.

In comparing the two types, low-temp machines only require 120 volts of power, but dishes come out wet. With high-temp units, dishes come out hot and, therefore, dry more quickly, but either 208 or 220 volts are required to operate the machine.

Undercounter warewashers typically accommodate one rack per cycle. Staff remove this rack once the wares are clean and then load in a different rack with dirty dishware and glasses.

Fill and drain machines are available in partial and complete variations. With complete fill and drain machines, 100 percent of the rinse water drains out once the wash cycle completes. With this type of unit, there is never water in the tank, except during the wash cycle.

Partial fill and drain units use 100 percent of the wash water and drain all of it, then bring in the rinse water before sanitizing. The unit uses the rinse water for the next wash cycle. These types of units are suitable for operations washing heavily soiled items.

In addition to fill and drain warewashers, foodservice operators can specify an overflow unit. These types of units reuse the wash water cycle after cycle and incorporate fresh water for rinsing. The cycle is broken when the unit is powered down and drained. Overflow warewashers are generally utilized with less soiled items, such as glassware.