The commercial dishwasher is one of the most heavily used appliances in any kitchen – it runs every day, sometimes for ten hours straight. The most expensive mistake is choosing a machine by price rather than by need: you end up without clean glasses, the dishwasher operator’s back aches and the kitchen is full of steam. In this guide, we explain how to choose the right machine – glass washer, front-loading, hood-type, rack conveyor or utensil washer – and what to look out for.
In short: five questions to ask before you buy
- What are you washing? Glasses, dishes, or pots and trays – each has its own type of machine.
- How much? How many racks need washing in your peak hour – this determines the size of the machine.
- What is your water like? Hard water ruins both the washing result and the machine; spot-free glasses need reverse osmosis.
- Where does the steam go? The moisture released by the machine must be removed from the room – with heat recovery or proper ventilation.
- Who maintains the machine? A dishwasher has to work every day, so fast servicing and spare parts are essential.
Always choose the machine to suit your needs
A typical story from our experience: a customer needs a machine for washing glasses. A quality glass washer seems too expensive, so they buy a cheap hood-type dishwasher instead. Then they ask the detergent supplier for a reverse osmosis filter in front of the machine and for detergents that will make the glasses sparkle. The result is endless arguments between the machine seller, the chemical supplier and the customer – because the one thing that is missing is clean glasses.
The cause is neither the detergent nor the filter, but the fact that the machine was not designed for the job. Each type of machine is built for its own task, and no amount of extra equipment will turn a cheap dishwasher into a good glass washer.
Glass washer – quality glassware deserves a quality machine
Glasses should be washed in a glass washer. A machine designed for glasses has the right wash pressure, temperatures and programmes, and the better glass washers usually also have a soft start function: the wash pump starts gently so that delicate and tall glasses do not tip over or break.
If you do not have a separate glass washer, the last-resort solution is to wash the glasses first in the dishwasher, then the dishes, and change the water in the machine afterwards. Greasy wash water full of food residue will never give glasses a sparkle. We cover glass washing in more detail in our guide How to choose a glass washer?
When should you choose a glass washer with reverse osmosis?
Rule of thumb: if your wine glasses cost from around €35 each, choose a glass washer with a built-in reverse osmosis unit. Reverse osmosis removes the minerals from the water that would otherwise remain on the glass as spots when it dries. Glasses come out of the machine sparkling, do not need hand polishing, break less often and stay beautiful for longer. Examples include Meiko M-iClean machines with the GiO MODULE and the Comenda HB35 RO and YB35 RO.
Why can’t a reverse osmosis filter be fitted in front of just any machine?
A reverse osmosis filter significantly reduces water pressure and flow rate. In most standard dishwashers the boiler is closed, i.e. pressurised: it is connected directly to the water mains and requires a stable pressure of 2–6 bar. Water from a reverse osmosis unit, however, comes slowly and at low pressure, so the boiler does not fill properly, the machine shows error codes and the rinse is weak. Excessive back pressure also damages the filter membrane.
To work with reverse osmosis, the machine must be designed for it:
- an open (atmospheric) boiler (a “breathing” boiler, e.g. Comenda RCD – Atmospheric Booster) – the boiler fills via a float valve and does not depend on the incoming water pressure;
- a pressure pump inside the machine – ensures the correct, consistent rinse pressure regardless of the water mains.
Only then will reverse osmosis work reliably and deliver the result it was installed for.
Commercial dishwasher – undercounter or hood-type?
When choosing a commercial dishwasher, consider how many dishes you need to wash:
- A front-loading (undercounter) dishwasher suits a café, bar or smaller restaurant. It fits under a worktop and washes up to around 40 racks per hour.
- A hood-type (pass-through) dishwasher suits a restaurant, hotel or canteen. It washes 40–75 racks per hour and is ergonomic – the rack slides from the table into the machine and back onto the table, with no bending and no lifting of heavy racks. This saves both time and the dishwasher operator’s health.
- A rack conveyor (tunnel) dishwasher suits large-scale kitchens, hospitals and ships, where hundreds of racks are washed every hour.
If you have a lot of dishes and are torn between an undercounter and a hood-type machine, it is often worth going straight for the hood-type. With an undercounter machine, the operator bends down for every rack, and in the long run that costs more than the price difference between the machines.
When calculating capacity, base it on peak-hour demand: a 500 × 500 mm rack usually holds about 18 plates. The manufacturer’s maximum capacity assumes the shortest programme and the next rack going in immediately – in practice, the actual capacity is lower.
Utensil washer – plan for your largest item
Choose a utensil/pot washer that can take the largest pot, pan or tray in your kitchen – measure them before you buy and compare them with the machine’s rack size and door opening height.
If it is not a granule pot washer, make sure the machine has good water pressure during the wash cycle. The larger the machine, the more powerful the wash pump needs to be. In addition, there should be a separate rinse pressure pump to ensure a consistent, hot rinse.
Granule pot washer – for the dirtiest items
A granule pot washer must also be able to take the largest item you use. The granules wear down and need topping up from time to time, so they are an ongoing running cost of the machine.
However, if the items going into the machine are very dirty or always dried on before washing, there is currently no better solution than a granule pot washer. It does everything a standard utensil washer does, but in addition the granules safely remove burnt-on and dried-on dirt – without pre-soaking or scrubbing.
Ventilation – applies to every machine
Whichever machine you choose, think about ventilation too: the moisture released by the machine must be removed from the room, otherwise staff, walls, ceilings and other equipment all suffer. There are two solutions:
- A dishwasher with heat recovery – the machine captures the heat from the released steam and uses it to heat the incoming water. Much less steam comes out of the machine, and you save energy too.
- A two-way ventilation system – the dishwashing area must have both extract and supply air. Extract alone is not enough, because the air has to be replaced from somewhere.
Wash arms: plastic, stainless steel or chrome-plated brass?
There is a lot of debate about whether dishwasher wash arms should be plastic or stainless steel. As the old saying goes: each to their own.
- Plastic wash arms on a quality machine generally last at least as long as stainless steel ones. They also often have better water jet distribution – water is spread more evenly in the machine and the washing result is better.
- Stainless steel wash arms are durable, but usually simpler in design and less able to distribute water evenly.
- Chrome-plated brass wash arms, found in some cheap machines, are the worst solution: once the chrome layer is scratched, strong washing chemicals quickly eat away the brass.
With a very cheap machine, however, it makes no difference what the wash arms are made of – such machines generally do not deliver any real washing result at all.
What else should you consider?
- Water softening – hard water causes limescale in the machine and spots on the dishes. Most machines need a water softener; some models have one built in.
- Drain pump – needed if the drain is higher than the bottom of the machine.
- Tables and pre-rinse – for hood-type and rack conveyor machines, plan a dirty and a clean table, a pre-rinse shower and suitable racks.
- Detergents – dose correctly and use the type of detergent recommended by the machine manufacturer.
- Maintenance – a dishwasher is in use every day, so choose a machine for which maintenance and original spare parts are quickly available in Estonia. Read also how to choose a maintenance partner.
Frequently asked questions
Can I wash glasses in an ordinary dishwasher?
You can, but the result will not match a glass washer. If you do not have a separate glass washer, wash the glasses first, then the dishes, and change the water in the machine afterwards. For expensive glassware, choose a glass washer with reverse osmosis.
Can a reverse osmosis filter be added to an existing machine?
Only if the machine is designed for it – it must have an open (atmospheric) boiler and a built-in pressure pump. A reverse osmosis unit reduces water pressure, so a standard machine with a closed boiler will not work properly with it.
Should I choose an undercounter or a hood-type dishwasher?
For small volumes of dishes, an undercounter machine is enough. If you have a lot of dishes and washing takes up much of the day, choose a hood-type machine – it is faster and more ergonomic, and it spares the dishwasher operator’s back.
Does a commercial dishwasher need ventilation?
Yes, every machine releases moisture. Either choose a machine with heat recovery, which significantly reduces steam, or plan two-way ventilation for the dishwashing area, with both extract and supply air.
Ask for a quote
Haktek Seadmed will help you work out what and how much your kitchen washes, and choose the right machine from the Meiko and Comenda ranges – complete with water treatment and ventilation solutions. You will find the full range in the Dishwashing and accessories category.
Ask for a quote – we will help you choose the right commercial dishwasher and take care of installation and maintenance. All products come with a warranty of at least 2 years. Contact us.
Read also: How to choose a glass washer? · How to plan a professional kitchen? · How to choose a maintenance partner for kitchen equipment? · How to choose a combi oven?
Author: Gert Laineste, Haktek Seadmed. Haktek has been selling, installing and maintaining professional kitchen equipment since 1997.
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