An Introduction to Commercial Warewashers

Almost any item can be cleaned in a warewasher but certain items are better handled in some units than in others.

For the best cleaning capabilities, it's important to understand the impact different washing methodologies have on various types of materials and composites.

Water in dishwashing generally must be heated to 180 degrees F for sanitization; maintained at 150-160 degrees F for washing; chemically treated with detergent and rinse additive; and then drained into the sewer system. Generally, oils and fats need to be heated to at least 110 degrees F to be broken down properly.

There are a number of warewasher types designated for different types of foodservice operations with a variety of volume needs.

The main types of warewashers include undercounter; door-style; rack or circular conveyors; flight-type or rackless; pot, pan and utensil; and continuous pot and pan washing systems, which are three-bay sinks with a wash pump.

Certain units also are best used for washing particular items. For example, dedicated glass washers have a longer wash cycle and lower water pressure so that fragile glassware is not damaged during washing. By contrast, dedicated pot-and-pan washers and tray washers use higher water pressure and longer wash cycles to better remove heavier soiling.

Capacities are determined by how many items can be washed per hour. While the majority of glasswashers can clean 1,000 to 2,000 glasses per hour, smaller single-rack undercounter and door-type dishwashers handle between 21 and 60 racks per hour.

Larger operations are more likely to utilize rack or circular conveyor warewashers, which handle between 100 and 300 racks per hour. For banquet operations and institutional settings, flight-type or rackless conveyor units can clean more than 21,000 dishes per hour.

Specialty warewashers, such as pot, pan and utensil washing machines, can have between a 6- and 60-pan capacity, depending on the unit.

Because of electricity and water use warewashers are one of the back of house's biggest energy users. Most are electric, but some models offer steam or gas water-heating systems.

Features vary on these units, but most have stainless steel construction, door safety switches, idle pump shut-offs, tank heaters and low-water tank heat protection.

Heat recovery systems capture steam coming out of the warewasher and redirect it out of the space and/or repurpose it as a heat source for the unit to help save air conditioning and electricity costs.

Newer ventless door machine models don't require exhaust hoods.

Also, variable speed conveyor warewasher models correlate the water to the belt speed to help increase efficiency in operations with varying cleaning volume.
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