BUYING A COMMERCIAL DISHWASHER

TYPES OF COMMERCIAL DISHWASHER

The three most common types of commercial dishwasher are undercounter dishwashers, pass-through dishwashers and conveyor dishwashers, each with valuable benefits to different types of caterer.

TIP: Whichever type you choose, using a commercial dishwasher means you’ll be able to reach rinse temperatures of up to 82°C, heats that can’t be guaranteed when handwashing. This makes cleaning your equipment with a commercial dishwasher the only way to ensure effective sanitation when washing - protecting staff and customers against transferrable viruses and bacteria.

Undercounter Dishwasher

Commercial Undercounter Dishwashers are compact and fit well into small to medium size establishments such as cafés, village pubs and small restaurants. These models usually require manual front loading and emptying.

Undercounter dishwashers can typically wash up to 500 plates per hour.

• Compact design: can be positioned where they are needed. Perfect for smaller sites.
• Rapid wash: much faster than domestic dishwashers. Cycles are usually around three minutes.
• Front loading: easy to access and clean.

Pass Through Dishwasher

Pass Through Dishwashers are large commercial units with technology similar to undercounter versions. However, the distinctive shape is designed so that plates can be Pre-Rinsed and loaded onto Dishwashing Racks during washes, speeding up the whole washing process.

Pass through dishwashers can typically wash between 600 to 1200 plates per hour.

• Large size: designed to make the dishwashing process more productive and efficient. Position a pass-through between two Dishwasher Tables for maximum effect.
• Rapid wash: although pass-throughs tend to wash at the same speed as equivalent undercounter dishwashers, the dishwashing process is faster due to quick loading and operation.
• Working height: as the user pulls the hood down, there’s no bending down - making a pass-through much more ergonomic than an undercounter version. However, the height could prevent some staff from operating the machine.

Conveyor / Rack Dishwasher

Conveyor Dishwashers offer the most automated, high volume cleaning, where racks of crockery and glassware are automatically channeled through a large chamber. Often called rack dishwashers, this type of machine can usually wash hundreds of racks per hour – perfect for busy school or staff canteens.

Pass through dishwashers can typically wash between 1700 to 2300 plates per hour.

• Large size: designed to make the dishwashing process more efficient. Position between dishwasher tables with pre-rinse for maximum effect.
• Time saving: in comparison with smaller dishwashers (or hand washing), a conveyor is vastly more productive. What might normally take all day could be done in an hour.
• Drying option: some premium rack dishwashers can have your plates ready to use again in minutes, thanks to a handy drying chamber.

INSTALLATION AND POWER REQUIREMENTS

Despite advances in technology, all modern commercial dishwashers still tend to use significant amounts of water and power. As such, many would require a direct “mains” water and power connection, although some smaller versions may be able to operate via a standard three-pin 13A plug. For more information about these types of power supply, see the Single Phase vs 3 Phase Power guide.

It’s also important to consider positioning. Is the washer close to the water and power supply? Will it fit through the doors? In undercounter models, will opening the door during loading and unloading create an obstruction or trip hazard to passing staff?

Some dishwashers can release a lot of steam when opened, so installing an overhead extraction canopy can make a much more comfortable working environment, especially so in smaller kitchens.

Professional installation is recommended on most commercial dishwashers, as it's much more than just hooking up the water and power. Getting installation right from the start ensures a fully functional and efficient washing solution. Larger units, especially pass-through or conveyor dishwashers often require a site survey prior to installation. More detail is available on these product pages.

GRAVITY DRAIN OR DRAIN PUMP?

During the washing cycle, commercial dishwashers dispose of dirty water by draining it away by either gravity or powered pump. If the dishwasher waste outlet is lower than the drain standpipe, a drain pump is required - otherwise water would need to go against gravity to drain away. The diagram below illustrates the two types.

If a drain pump is required, they can be purchased pre-fitted with most dishwashers. Alternatively, external drain pumps are available through the Spares and Accessories category.

Check and double check the planned location before purchase to confirm where the drain is in relation to the machine’s waste outlet. In some circumstances, a gravity drain model may be suitable simply by placing it on a compatible dishwasher stand which raises the waste outlet. This gives the additional benefit of making the dishwasher a more comfortable and accessible working height for staff.

RINSE BOOSTERS & WATER PRESSURE

As all commercial dishwashers use powerful water jets to effectively clean the contents, it's important that there's enough water pressure to feed those jets.

Every site is different and water pressure can be affected lots of different things. For example, even a single hand wash basin could reduce the effectiveness of a washer if there's not enough pressure. The general rule is washers need around 2 bar water pressure.

If there's insufficient water pressure, the washer will need to be fitted with a rinse booster pump. This can either be fitted externally or pre-installed internally when you buy the washer. Either way, it's a vital consideration, so make sure to check your water pressure before you buy a washer.

TIP: An easy way to test water pressure is the 'thumb test'. Simply block off the spout of a tap with your thumb and turn on the water. If you can completely prevent any water exiting the tap, you may well need a washer with a rinse booster pump. A site survey can identify whether a rinse booster pump is required.

LIMESCALE & WATER SOFTENERS

In hard water areas, limescale can quickly build up on internal dishwasher components. This can rapidly affect the performance and efficiency of the dishwasher. If left untreated, the machine could fail and potentially lead to a chargeable out-of-warranty repair.

The recommended way to combat this is to use a Water Softener, which breaks down and filters the calcium carbonate (limescale) in the water before it enters the machine.

There are two standard types of dishwasher water softeners available: manual and automatic . Both require occasional regeneration to work at their full potential, however automatic versions can be programmed to do this outside of your service hours. Manual water softeners require a member of staff to manually add Dishwasher Salt much more regularly than in automatic versions.

Some premium dishwashers feature a built-in internal automatic softener, as well as a warning indicator on the machine to prompt the user when the softener requires additional salt - very convenient for busy sites.

TIP: Water softeners aren’t always absolutely necessary. The water hardness map can be used as a general guide to help, although it’s worth checking with your water supplier to be absolutely sure.

Dishwashing Chemicals

In order to clean crockery thoroughly, commercial dishwashers use intelligent washing cycles combined with careful dosing of dishwasher detergent and rinse aid. These products are typically purchased in 5 Litre containers.

Depending on the dishwasher, the chemical is drawn into the machine via internal chemical pumps to ensure the exact amount is used. The dosing is usually set at the time of installation, a process called commissioning.

As different chemicals have different concentrations, it’s important to read the instructions on the container to ensure the correct dilution is used. Commissioning is usually included when you purchase installation alongside a new dishwasher.

New and replacement chemical pumps can be found within the Spares and Accessories category.

Frequently Asked Questions

What’s the difference between a commercial dishwasher and glasswasher?

As the name suggests, a glasswasher is specifically designed to clean glassware. Dishwashers tend to reach higher temperatures - perfect for dirty utensils and plates. A glasswasher takes care to keep delicate items such as champagne flutes and dessert glasses intact and sparkling.

Can I use a dishwasher as a glasswasher?

It’s not usually recommended to wash glassware in dishwashers, mainly due to the intensive nature of the washing inside. That said, some premium Winterhalter dishwashers have the option to be re-configured on-site for use as dedicated glasswasher if required.

Can I use a glasswasher as a dishwasher?

Glasswashers aren’t designed for the intensive, high heat washes that dishwashers produce. As such, the results won’t be as good or sanitary as a dedicated commercial dishwasher.

Can I wash GN pans in a dishwasher?

Yes - although smaller washers might not be big enough for your larger pans. If you want to wash the largest double-size GN pans and large cooking pots, it might be worth considering a utensil washer, as these are specifically designed for this type of cleaning.

What is a bistro dishwasher?

A bistro dishwasher is simply a machine which can clean glassware, crockery and utensils all together. These flexible machines can be a great choice if space is limited, however dedicated dishwashers or glasswashers are usually preferable if you're washing in bulk.

Why does cutlery rust in my dishwasher? It’s stainless steel!

Firstly, a common misconception is that stainless steel can’t rust. It can. See our How to Clean Stainless Steel guide for more information. The best advice to prevent rusting or “pitting” in cutlery and other utensils is:

• Wash silver and stainless steel items in separate loads if possible. If not, keep silver cutlery in separate parts of the dishwasher.
• Pre-rinse food off cutlery and utensils before washing. Acidic or salty residue can quickly seep into microscopic holes in stainless steel.
• Ensure correct detergent and rinse aid dosing. If you have a water softener fitted, excess dishwasher salt could also be causing rust.