Foodservice Equipment Reports

FER FOCUS: Dish Detail 2.0

Dish rooms in a lot of restaurants are hot, damp, dirty workspaces, and those conditions typically are why it’s hard to keep good employees working in them. But dish detail doesn’t have to be like that. Equipment manufacturers continue to improve warewashers, making them run cooler and quieter than ever.

Since the implementation of Energy Star’s Version 2.0 specs for dishmachines in February 2013, many models are more energy and water efficient than ever. The U.S. Environmental Protection Agency estimates you’ll save at least $1,300 a year with an Energy Star-approved machine. Typically, they’re about 40% more efficient than models that don’t sport the Energy Star label.

Stationary, single-tank, door-type machines fill a nice niche between smaller undercounter dishmachines and rack conveyor machines. Strong and powerful enough to handle pots and pans, these workhorses can wash up to 60 racks an hour (if your employees can load/unload that fast), or as many as 1,200 dishes, in a small footprint of a little more than 4 sq. ft., not counting feed and landing tables.

Actual cycle times typically range 55-90 seconds, but the number of customers one of these machines can handle depends on your tableware. A high-end bistro with more tableware per guest than a midscale restaurant will experience lower productivity. A sandwich shop with small 8-in. plates, for example, will be able to rack more dishes per cycle than, say, a Mexican restaurant using oval platters. If you plan on washing a lot of sheet pans, spec a machine with higher door clearances.

Operations that find door-type machines most useful are restaurants with 100-150 seats; high-volume quick-serve units that use disposables and only need to wash pots, pans and parts; or larger stores that want a separate machine for pots and pans or even just glassware.

Running Hot And Cold

Finally, the type of food you serve will be a factor in your decision. Most manufacturers make both high- and low-temperature, chemical sanitizing machines. Hot water is more effective at removing greasy, sticky soils, including high-protein foods like egg yolk and melted cheese or greasy residue from fried foods. Low-temp machines can clean light soils very effectively and offer their own advantages that we’ll discuss later in this article.

The ultimate purpose of warewashers is to clean and sanitize dishes and utensils. To pass most local health codes, dishmachines have to meet NSF/ANSI 3: Commercial Warewashing Equipment standards. NSF/ANSI 3 sets the parameters for wash- and rinse-water temperatures, chemical-sanitizer concentration, etc. Energy Star sets the bar for how efficiently dishmachines achieve NSF standards.

There are two ways to sanitize dishes, utensils and cookware: using heat or chemicals. High-temp machines use a higher wash temperature and a final sanitizing rinse of fresh water heated to 180˚F-195˚F. NSF/ANSI 3 requires the surface temperature of whatever is being rinsed to be heated to 165˚F for at least 15 seconds to kill any microbes that might linger after the wash cycle.

Low-temp machines use 120˚F-140˚F wash water and a chemical sanitizing solution (usually chlorine or iodine) in the final rinse to kill microbes. Because they don’t require a lot of power to heat water, most low-temp units run on 115V electrical service, making them suitable for a variety of applications in which lighter soils are the rule, such as sandwich shops, or areas where electrical service isn’t adequate to power a high-temp machine.

Many chemical suppliers also offer low-temp machines on a lease basis, requiring a lower upfront investment. Longer term, of course, the cost of chemicals can outweigh the initial expense of high-temp machines. Energy savings in low-temp machines are dependent on local utility costs but may provide an advantage over high-temp machines where electricity is inexpensive.

Veni, Vidi, Ventless

You easily can find equipment that provides energy and water savings by looking for the Energy Star label. As you can see from the table below, Energy Star-qualified dishmachines have to achieve or exceed ratings for water usage per rack and energy usage during idle periods. You can find a list of which models have qualified to use the Energy Star label on the program’s website,

When comparing models, you’ll see manufacturers quote figures for water consumption and racks per hour, which will help you compare one model to another, but how a machine performs in a lab isn’t necessarily the same as how it performs in the field. The amount of energy and water savings you get in your stores, even with Energy Star-labeled equipment, will depend on a host of variables, some of which you can control and others that may be more difficult to handle.

For example, if you train your dish-room employees to scrap properly and load racks efficiently, you’ll run the machine through fewer cycles, saving both water and energy. On the other hand, if the temperature of your incoming water is inconsistent and you need a booster capable of a 70˚F degree rise, you may end up having higher energy costs than expected.

Also, note that when the EPA created the latest version of Energy Star standards, requirements for high-temp machines got more stringent, but those for low-temp machines didn’t change. Therefore, the onus has been on high-temp-machine manufacturers to do the same job using less water and energy, at least at idle rates.

Manufacturers have responded with a couple of clever innovations. The first is a “ventless” machine. Most local codes require that the heat and humidity from dishmachines be vented outside, which means installing a Type II hood. Ventless dishmachines eliminate the need for a hood by including a condensing coil in the machine. The condensing coil contains incoming cold water. As hot humid air rises in the machine, the water vapor condenses on the coil and drips back into the tank and the heat is transferred to the incoming water. By buying a ventless unit, you get the dual benefit of saving on the cost of a hood as well as some of the energy that would have been required to heat wash water in the tank. An added bonus: Because you don’t have to supply make-up air to the dishroom hood, you’ll save on HVAC costs, too.

If you go with a ventless unit—and who wouldn’t, especially in newly built stores—make sure the machine also has a self-cleaning feature for the condensing coil. The coil must be cleaned periodically to prevent the growth of bacteria or mold, which thrive in warm, humid conditions. A self-cleaning option creates less guesswork for employees.

A second innovation that’s offered on many models is “active water filtration.” That’s a fancy way of saying the wash water is filtered continuously, usually through several screens. Instead of waiting until the end of the day to clean them, the machine automatically flushes the screen filters after each wash cycle, removing dirt and food. Cleaner wash water results in better cleaning performance over the course of many cycles and requires less detergent.

Getting Down and Dirty

While there are perfectly good door-type machines out there with a simple on-off switch, following are some of the features and benefits you should consider:

Construction. Per NSF/ANSI 3, dishmachines should be constructed of stainless nearly throughout, but design differences exist among the various makes and models. Look for double-walled construction of the doors, hood and even sides. Insulated machines retain heat, improving energy efficiency, and dampen noise. 

Machines may have doors or a three-sided hood that employees lift with handles. Look for models where the doors or hood can be raised easily with one hand. The doors/hoods on virtually all units will fit under standard ceiling heights, but if you need a taller machine to accommodate sheet pans, double check to make sure ceilings in your stores are high enough to clear the door when it’s raised. 

Pumps. Most models use a 1-hp motor in a pump with a stainless impeller. Some models feature a 2-hp pump, giving you plenty of wash power. If you plan to use your machine for scrubbing pots and pans or have a menu heavy in eggs or cheese, the extra power is probably a good idea. Be sure the model you choose uses a self-draining, vertically mounted pump so water doesn’t sit in the pump between cycles or when the dishwasher is not in use. Otherwise, bacteria can build up, making the next day’s cycles less sanitary, and the pump becomes susceptible to corrosion.

Because the final-rinse cycle is independent of the machine’s wash pumps, it depends on incoming water pressure to your store, which can vary. Several dishmachine models are available with rinse pumps. The advantage is that you get a more dependable pressure of fresh rinse water, and pumped rinse water provides better coverage, makers say, ensuring your loads are sanitized properly. Rinse pumps typically are smaller than wash-tank pumps, usually ranging ½-1 hp.

Heaters. Heating elements (or gas-fired burners) have to maintain proper wash-water temperatures (120˚F-140˚F for a low-temp machine; 160˚F for a high-temp machine). Most makers offer options on heater power depending on your incoming-water temperature.

Most models also give you the option of a built-in booster heater to warm sanitizing rinse water to at least 180˚F, per NSF/ANSI 3. The advantage of a built-in vs. an external booster heater is that they are pre-wired, pre-plumbed and usually don’t take up additional space in your already cramped dish room. Booster heaters usually are sized to provide a rise of either 40˚F (for incoming 140˚F water) or 70˚F (for incoming 110˚F water) depending on the temperature of the hot water feeding into your kitchen. Be sure to spec the booster properly to accommodate the rise in temperature you need it to produce.

Spray arms and nozzles should give you full coverage no matter what type of rack—glass rack, dish rack or flatware rack—you use. Make sure they are easy for employees to disassemble, clean and reassemble. Many manufacturers build machines with interchangeable upper and lower spray arms to make the process smooth. Wash and rinse arms usually have different designs, though, making it nearly foolproof to put the right pieces back in place after cleaning.

Wash tank. The size and shape of the wash-water tank can affect efficiency and performance. Some manufacturers say the larger tanks on their models retain more washwater heat and tend to be more efficient. At least one maker claims that a deeper tank design does essentially the same thing. But larger tanks also take longer to warm up at the beginning of the day. Another feature to look for: Most washers these days are designed with coved corners in the tank for easier cleaning.

Filtering. Some manufacturers offer one-piece scrap baskets, others market two-piece units that double-filter debris and soil. Whatever the design, scrap baskets should be easy to get to, remove and clean. As mentioned earlier, some models are designed with active filtration so water flows one direction during the wash cycle, trapping food and debris, then flows the other direction at the end of the wash cycle, flushing soil out of the scrap basket and down the drain.

Under Control

As with many other equipment categories, some of the biggest changes in door-type dishmachine design in the past five years have to do with the switch from electro-mechanical to electronic controls. Following are some other features you might want to consider:

Variable cycle. Base models offer a single cycle, but some models give you a choice of two or even three cycles. The variable simply may be a longer wash cycle, while the rinse cycle remains the same from one “mode” to the next. More models, however, give you control over the time of the cycle and the wash water pressure, which lets you wash everything from delicate china or glassware to pots and pans.

Automatic cleaning and deliming. Some models have an optional delime cycle that automatically washes the inside of the machine with scale remover. At the very least, look for models with a deliming warning light. A few models also offer a self-cleaning cycle.

Programmable electronics. Newer models feature electronic controls that provide self-diagnostics, telling you if something goes wrong with the machine or when it needs service. Some can be programmed for the exact wash cycle your stores need. Several models can communicate with PCs, tablets and other mobile devices, letting you monitor and record HACCP data, such as wash and final-rinse temps, and alerting you when machines need deliming or servicing.

Safety features. Standard safety features on most models include a door switch that turns off the machine when the door is opened and a low-water shutoff that turns off the heating elements if the water in the tank is too low. The door switch also lets employees start the machine every time they load a rack by simply pulling the door closed.

Options available on some models include a rack sensor and temperature interlock. The former saves energy by running only when it senses the presence of a rack in the machine. The latter won’t run the machine unless wash and rinse water are at their proper temperatures.

There are more than enough models on the market to choose from, so you’ll find one that fits your needs as well as your pocketbook. Don’t forget to compare service networks and warranties, but read the fine print to see what is included.


Coming Clean

Maintenance and a few sensible tips are keys to getting the best performance from your door-type dishmachine.

• Provide at least 48 in. of worktable—enough to hold two racks of dishes—on either side of the dishmachine. This will give your employees adequate feed and landing space for loading and unloading dishes. Most modern machines can be field-retrofitted for straight-line or corner setup.

• Scrape dishes thoroughly before loading racks. The faster your wash water gets dirty, the more detergent you have to use and the less clean the results.

• Check wash- and rinse-water temperatures. Most machines now have thermometers with digital LED readouts, but it doesn’t hurt to check their accuracy periodically.

• Clean out the machine between each shift or more often if needed. Again, dirty water affects the machine’s cleaning ability and can clog spray nozzles. 

• Wash the entire machine daily. Disassemble and clean spray arms; empty and wash scrap baskets. Leave the machine open to dry overnight.

• Use the right racks. Racks that aren’t properly matched to the wares you’re washing not only can prevent dishes from getting clean but also may result in more chipped or broken glasses or tableware. Spacing of the pegs in a rack could be too far apart for small dishes or too close together for large plates. The individual compartments in glass racks should be sized to fit the glassware’s diameter.

• Use detergent and rinse agents in the right amounts. If you don’t use an automatic dispenser, measure chemicals to be used in the machine.

• Filter and treat incoming water if necessary. Detergent doesn’t work well in hard water. Most dishmachines, especially low-temp models, clean better with water that contains only 2-4 grains of hardness. A filtration system that removes sediment and some minerals will help. You may need a water softener, too. Check your warranty: Water filtration might be part of the agreement, and failing to filter might render the warranty void.

• Delime the machine as necessary. Watch for a white haze on interior walls, spray arms and nozzles and prevent scale buildup by following manufacturer recommendations.

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