Warewashers

By Staff -- Foodservice Equipment & Supplies, 9/1/2006

Types: Warewasher models include undercounter, doortype, flight-type or rackless-conveyor, rack conveyor-type dishmachines, upright conveyors and circular conveyor-type units. Some warewashers are designed to clean specific types of wares, such as glasses, pots and pans, and utensils. Several niche warewashers are also available. Some manufacturers offer countertop warewashers that clean just a few glasses or plates at a time. Their capacities make them ideal for bars, mobile carts, and ice cream or limited beverage service operations. Also available are specialty warewashers for glasses that consist of a set of spinning brushes installed in a small dish sink. Such systems are typically installed at bars in the front of the house, eliminating the need to take glassware to the back for cleaning. Many warewashers meet standards set by healthcare associations.

Capacities/Footprints: The racks or glasses per hour they can wash will distinguish warewashers. Undercounter dishwashers and door-type machines generally wash between 21 to 55 racks per hour, while a glasswasher can wash 1,000 to 2,000 glasses per hour. Flight-type or rackless-conveyor units can wash more than 21,000 dishes per hour at an NSF-rated belt speed of 13.6'/min. Single-tank and multiple-tank rack conveyors can be adjusted to wash up to 288 racks or 28,000 dishes per hour at a maximum conveyor speed of 10.9'/min. Pot, pan and utensil washing machines can have a 6- to 60-pan capacity. Circular conveyors can wash a maximum of 122 to 320 racks per hour at a conveyor speed of 3.4' to 9.0'/min.

Undercounter dishwashers and door-type machines are the most compact, function best and are best suited for use in smaller kitchens. Undercounter dishwashers usually do not exceed 23" wide x 25" deep x 53" high in overall dimensions. Door-type machines are also designed to conserve space, while providing high production in small dishroom areas. Door-type machines are typically approximately 26" wide x 25" deep x 92" high. Glasswashers can be as large as 72" wide x 22" deep x 38" high. Upright conveyor systems offer high-volume operators continuous dish rack or direct drive loading. Conveyor systems’ largest section can be 4' wide x 7' to 10' high.

Energy Source(s): The majority of warewashing machines operate on electric power levels ranging from 115V for smaller machines to 460V for larger units. Some warewashers offer the option of either electric, steam or gas water-heating systems, while others are available only with single-source gas-heating systems.

Standard Features: While most warewashing machines are constructed of stainless steel and almost all feature common utility connections, door safety switches, idle pump shutoffs, tank heaters and low-water tank heat protection, almost all other features vary greatly.

Undercounter dishmachines, for example, can include built-in electric booster heaters, “airglide” door designs, fully automatic wash and rinse cycles, self-sealing gasketless doors, upper and lower wash and rinse spray systems, removable rack glides for easy cleaning and flexible hoses designed to make installation easier.

Door-type machines, which are designed for opera tions with limited space, typically feature automatic tank fills, door-activated drains, front-mounted tanks for easier cleaning, built-in 40° or 70° rise booster heaters, straight-through or corner-model configuration, top-mounted controls, interchangeable upper and lower spray arms, 1-hp pump motors and detergent/chemical connection provisions.

Flight-type or rackless warewashing units usually feature dual fresh-water rinse functions. The systems’ large removable panels and inclined, self-cleaning tanks are designed to simplify daily maintenance. Designed with energy efficiency in mind, these systems’ double-wall insulation reduces noise and retains heat. Wash-arm warewashers maximize pressure, which can result in superior soil removal.

Rack conveyors usually feature automatic tank refill, leak-proof doors, rinse-saver devices, 2-hp wash pumps, a door-activated drain closure, removable spray arms, convenient top-mounted controls and interchangeable spray arms.

Upright warewashers usually have extra-wide conveyors for high-capacity operations. Some standard features include idle pump shutoffs, rinse-savers, top-mounted control consoles, push-button start-stop controls on the load end, conveyor shut-off shelves on the unload end, common drains and electric connections, chemical dispensing connection provisions and water regulating valves. Upright conveyor systems also usually offer a choice of tank heat: electric, steam coils or direct-steam injectors. Some units feature access doors on both sides of the hood and clean-out doors on the end and sides of a machine for easier access.

Circular conveyor machines usually feature automatic tank fills, a choice of chain or upright conveyor peg belts, splash protection, start-stop stations and load-end and top-mounted controls.

Many types of warewashers are designed to clean specific types of items: pot and pan washers, utensil washers, glasswashers and the like. One reason for the existence specialized machines is that water comes out of a warewasher’s cleaning arms in a specific pattern. The farther away the arms’ nozzles are from the wares being sanitized, the more that pattern is lost. Cleaning is then less efficient. These specialized units, therefore, have arms positioned as close to wares as possible while still allowing room for clearance.

Glasswashers generally feature a built-in dispensing system for detergent, rinse additives and sanitizers, and an automatic conveyor drive system.

These single-switch machines feature separate wash and rinse temperature gauges, powerful wash pump motors and a 100-percent fresh-water rinse, which is designed to eliminate rinse-water contamination problems.

Pot, pan and utensil washers typically feature separate wash and rinse tanks; self-contained booster heaters; adjustable wash and rinse cycles with a selector switch; high-velocity spray nozzles designed for fast stripping action; an external pre-rinse wash-down hose; automatic fill functions on utensil models; heavy-duty racking systems; electric, steam or gas heating systems; and, sometimes, a loading ramp or pit grid for rack washers.

Warewashing machines can be customized to meet operators’ specific needs. For example, adding a motorized rack advance curve and a roller table to a rack conveyor machine allows a smaller dishroom to provide high-production warewashing. Cantilever sideloader tables, on the other hand, allow for loading of racks from the front of a machine, thus saving space in a smaller dishroom. Many machines can be programmed on-site with customized wash and rinse times that meet operators’ washing requirements.

Newly developed spray nozzles in conveyor-type warewashers can cut the amount of water required by 50 percent, thereby providing savings by reducing water usage, the amount of energy required to heat water and cutting rinse agent/chemical use. Such technology can offer an up-front saving by allowing operators to purchase a smaller water booster heater with their machines.

New Features/Technology/Options: Increasingly, high-tech features are being built into warewashers. Some manufacturers offer units that are compliant with the NAFEM Data Protocol. Also new on the market are handheld computer interfaces that can communicate with and control single or multiple warewashers. These interfaces can perform functions such as start-up, timed cycle selection and machine shutdown. They also allow for control of the internal booster heater and for service diagnostics, machine programming or to check individual operating components.

Since health codes typically require dishes coming out of a warewasher to reach and maintain a specified surface temperature, manufacturers offer sensors that can extend a wash cycle to ensure such temperature is attained.

For those machines that use racks, manufacturers offer various types of options designed to hold specific types of wares, such as trays and sheet pans. To wash plates, racks with pegs are most efficient, while pegless racks are designed for glassware and flatware.

Purchasing Guidelines: Since different wares have different washing requirements, operators must determine what they intend to wash in order to specify the correct unit.

Operators should also take into account how often dishes are used during a given period of time. A catering facility that uses each dish only once per night will not need a warewasher with as much capacity as an operation that reuses the same dishes several times.

Space considerations have led many consultants and operators to move away from specifying large flight-type machines. The space they require, they feel, would be put to better use in the front of the house, providing more room for revenue-generating customers.

Like many pieces of equipment, operators should consider the costs associated with the many consumables related to warewashing, such as detergent, rinsing agents and other chemicals. Many local codes require warewashers’ water temperatures reach a minimum of between 160°F. and 180°F. Using a building’s water heater to reach such temperatures can result in patrons being burned when they wash their hands. Operators should consider adding water temperature-boosting devices to their warewashers.

Maintenance Requirements: To maintain the performance of a warewashing machine, most manufacturers suggest using commercial-grade detergents and making sure water temperature and pressure do not exceed specifications. One common practice to keep machines operating smoothly is to run a wash cycle while the unit is empty. Staff can program some machines to run a cycle automatically after every wash.

Food Safety & Sanitation Essentials: Warewashing machines eliminate any contamination of cooking, eating and drinking utensils by effectively sanitizing wares at high water temperatures.