Dishwasher buying guide

Commercial dishwasher buying guide

Commercial dishwashers are an essential part of an efficient food service operation, or other food production environment like a bakery. Although the cost of purchase might seem high, particularly for larger machines like pass through systems, the labour saving and associated cost saving involved mean that the right dishwasher will pay for itself very quickly indeed.

This guide is intended as supplementary advice for dishwasher purchase on top of the essential advice given in our commercial warewasher guide for installers and purchasers. If you haven't read that we encourage you to do so first, as it covers the following important areas.

  • Break tanks and WRAS legal requirements
  • Servicing valves
  • Water pressure
  • Drain pumps
  • Water softener
  • Electricity supply
  • Hot vs cold water supplies

Once you are comfortable with the above, you will find you have already narrowed your options considerably, and can focus on choosing the best device using the following extra guidance.


Size and capacity

The most obvious factors to consider are external dimensions and internal capacity for crockery and cookware - unless you are designing your kitchen from scratch it will most likely be a case of measuring the space you have and then finding the machine with the highest capacity which fits. The custom search filters along the left hand side of Catering Appliance Superstore's range of commercial dishwashers will help you quickly narrow your search by brand and by plate capacity, and from there you can check the external dimensions of a reduced range of products.

We stock from 11 to 18 plate models, with 18 plates being sufficient for quite busy hotels and restaurants, but if you have especially high overall volume or extreme peaks of trading then you might want to consider a pass through or hood system.

To give you an approximate idea of the size of device you might need to keep pace with service, simply multiply the capacity of the machine in plates by an average washes per hour of 16 to 18, based on cycle of 3 minutes plus 30 seconds for loading and unloading and for temperature recovery time. Much is often made of the kw input to the dishwasher and how higher powered machines recover temperature faster ready for the next wash, but in the vast majority of cases your loading and unloading time is more than sufficient for the machine to do this anyway.

Once you've got your number of plates washed per hour, take just a third of your figure to account for the fact that to serve each customer there is a good deal more washing up than just the plate! If your customers generally eat two or three courses, you might even want to take a quarter or a fifth of the figure. If the end result is equal to or more than the number of customers you serve in an hour at peak trading, you should be fine.



The majority of dishwashers we supply are front loaded under-counter or cabinet dishwashers, generally positioned underneath work surfaces where they can be accessed perfectly fine. Remember most dishwashers open with a drop down door so you will need to allow room for this and to load and unload full trays, as well as to allow service staff past - consider that the machine will be opened for 10 to 20 seconds every 3 to 4 minutes during your peak service, which may not sound a lot but will become an irritation if the machine is poorly positioned. Avoid narrow gaps that are used as a thoroughfare for service staff.

Positioning on the floor is ok, but Catering Appliance Superstore can supply a general purpose universal washer stand to raise the dishwasher to a more convenient working height, and some of the models have multifit stands as optional extras within the product page. There are some efficiency benefits to dishwashers positioned at waist height, as staff will find it easier to load and unload the machine.

Finally, don't forget you'll need to position a decent sized drum of detergent and one of rinse aid somewhere quite close to the machine (note - only use commercial dishwasher detergent and rinse aid, the higher quality the better).


Drain pumps

The majority of the dishwashers stocked by Catering Appliance Superstore either include a drain pump as standard or can be fitted with one at a small additional cost. Drain pumps are necessary where drains are higher than the surface the dishwasher will be positioned on, and are in any case a good idea to ensure efficient draining each and every time the device is used.

There is more detailed guidance on drain pumps in the commercial warewasher guide for installers and purchasers.


Rinse boost pumps

If you're especially keen to ensure a very high standard of finish and sanitation, we recommend selecting a model with a rinse boost pump to ensure maximum power in the part of the wash cycle that adds the finishing touch and really gets your plates and other crockery sparkling.


Water softener

In hard water areas, it is strongly recommended that a water softener is used in conjunction with your commercial dishwasher to avoid a build up of limescale that will block jets and render the machine ineffective. Even in areas where limescale build up is less noticeable, water softeners are a good idea if you want to extend the working life of your dishwasher, or at least reduce the need for regular disassembly and deep cleaning of rotary jets.

There is more detailed guidance on water softener in the commercial warewasher guide for installers and purchasers.

By Philip Wearmouth | Catering Appliance Superstore