Dishwashers and Warewashers

The unit that best suits an operation depends on the kitchen, the restaurant’s volume and the items it will wash.

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A Guide to Warewashers

Warewashers can clean a variety of items. But some units may be better than others when it comes to cleaning certain items, like plastic trays and beer mugs.

Although warewashing tends to get overlooked because it does not generate revenue, the dishwashing area typically includes some of an operation’s most expensive equipment.

Dish machines can be broken down into five types: undercounter, door-style, rack or circular conveyer, glass washers and ventless.

Undercounter machines are built around 1 or 2 dish racks and clean in 45 seconds to 2 minutes.

Door-style machines come in single- and dual-rack models. These units are similar in style to undercounter types but are taller and connected to dish tables. Capacities range between 21 and 60 racks per hour. Door-type machines have many wash cycles for various cleaning needs. The normal cycle can handle glassware, like beer mugs and pitchers as well as plates and utensils. Pots, pans and heavily soiled items benefit from an extra heavy cycle, which is about 5 minutes versus 1 minute for regular washing and sanitizing.

Rack or circular conveyor units are continuous-motion machines with an average production rate between 100 and 300 racks an hour. Flight-type or rackless warewashers can wash more than 21,000 dishes per hour with belt speeds as high as 14 feet per minute. Pot, pan, and utensil machines are specialty units that hold 6 to 60 pans at one time. Larger operations can consider conveyor machines, available in 44- and 66-inch sizes.

Glass washers are small undercounter machines between 36 and 38 inches tall. Rotary-type machines wash and sanitize glassware in about 15 seconds, while other types have 90-second cycles. In the past, the only glass washers available were low-temp machines. Because these only heat water between 120 and 140 degrees F, chemical sanitizing was required. This type was preferable because no steam was released into the bar area when the door was opened after washing. However, the downside was the smell of chlorine and the possibility that sanitizing chemicals would impact the taste of beverages. Newer ventless glass washers have systems that eliminate hot and potentially damaging clouds of steam.

With ventless warewashers, there is often no need for hoods or exhaust fans since there is no steam that needs capturing. With these units, a fan draws steam out of the chamber at the end of the rinse cycle, pulling it into the warewasher’s heat exchanger. When the door is opened after the rinse cycle, no steam escapes. By pulling out the steam, the warewasher can utilize this to heat incoming wash water. This increases energy and saves money on electricity typically used for heating the water from 110 to 180 degrees for washing.

Before purchasing a ventless warewasher, operators should check local codes and requirements. Although this technology increases the cost of these machines, it can save money on utilities used for heating wash water as well as cooling kitchen environments over the long term.

Commercial dishwashers that have earned the Energy Star designation are on average 40% more energy efficient and 40% more water efficient than standard models, per Energy Star. The designation is for high-temp (hot water sanitizing), low-temp (chemical sanitizing) and dual sanitizing machines. This includes undercounter, single-tank, door-type, single-tank conveyor, multiple-tank conveyor and flight-type machines. Glass washing, pot, pan, and utensil machines are also eligible. Energy Star-certified flight-type machines can save more than 150,000 gallons of water annually.

Advanced controls and diagnostics, improved nozzles and specific rinse arm designs can save energy and water. Operators can increase a warewasher’s energy efficiency if units are run fully loaded, wash cycles are cut, and water pressure is at 25 psi or below.

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