Warewashing Buying Guide


Different Types of Dishwashers

There are various different options to choose from, including under counter, rack door, rack conveyor or extremely large continuous conveyor machines.  Some of these have single or multiple wash tanks and use different water temperatures too.  Water temperatures range from 43.3 Deg C to 60 Deg C.  If you have been advised to use a higher temperature, you can buy an additional water heater booster.  High temperatures are recommended for excellent cleanliness and for killing off germs.

Water Softeners

Commercial dishwashers need a soft water supply to work to their optimum ability.  There are different types of water softeners which can be installed:

  • Integral which are placed inside a dishwasher but commercial dishwashers do not run automatically, you need to remember to switch this type of softener on when using the dishwasher. Some high-spec dishwasher appliances have a mechanism to remind you to use the water softener.  These need to be topped up with salt regularly and are only recommended for areas with moderately hard water.
  • Continuous these work the same as those in a household dishwasher and need regular topping up with salt. These are suitable for use in moderate water quality areas.
  • Automatic cold these are suitable for use on a cold water supply and look like a small plastic box with switches. The box is plugged into the mains and operates automatically but you need to check the salt levels.   Boxes are often placed alongside the dishwasher or very close by for example, in a cupboard. Automatic cold water softeners are suitable in all water quality areas and are usually the most expensive.
  • Automatic hot these operate on a hot water supply and like the automatic cold they are very similar, suitable for use in all water quality areas these are usually the most expensive.
  • Manual these have a stainless steel cylinder which has a water inlet and outlet fitted close to the dishwasher (note: must have easy access). These need to be manually re-generated up to twice a week depending on how hard the water is in your area and how much you use your dishwasher.  Manual water softeners are suitable for all water areas but do need careful maintenance.

Glass Washers

Glass washers are very popular in bars, pubs and hotels and often are purchased in addition to a commercial dishwasher.  Especially for businesses which turnover plenty of drinks, there are various sizes to cope with your requirements, some able to wash up to 810 glasses per hour.

Drain Pump

Drain pumps are essential if your waste pipe or water exit is higher than your machine’s drain outlet, check where yours is to find out whether you need one or not.

What Size Commercial Dishwasher?

It can be confusing to know what size dishwasher you need for your business; this brief guide will give you some guidance:

Type Basket Size mm Glasses per hour washed
Glasswashers Front Loading 350 x 350 mm 380
  400 x 400mm 485
  450 x 400 mm 675
  500 x 500 mm 810
    Plates per hour washed
Dishwasher Front Loading 400 x 400 mm 195
  450 x 450 mm 250
  500 x 500 mm 325
Standard Extra Premium 400 x 400 mm 295
  450 x 450 mm 380
  500 x 500 mm 485
Standard Pass-Through 500 x 500 mm 510
Premium Pass-Through 500 x 500 mm Up to 900
Rack Conveyors 500 x 500 mm 1440 to 4590
Flight Conveyor   2020 to 8890


Points to Remember:

  • Dishwashers use up a lot of energy, use a lesser rinse cycle to save on energy and water.
  • Look for the most energy efficient type.
  • For a dishwasher to last you as long as possible buy a high quality commercial appliance.
  • A dishwasher is a far better way of cleaning your goods because there is less time wasted, better sanitary results and drying by hand can sometimes lead to cross-contamination.
  • Your dishwasher will need regular servicing and if you maintain good servicing, it will last you longer.
  • Always use good quality commercial dishwasher detergent and include rinse aid and salt where required. Check your dishwasher regularly to make sure it is topped up properly.
  • Never use domestic dishwasher detergent in a commercial dishwasher.
  • Don’t forget to check to see whether you need a drain pump.
  • For your dishwasher to work best you will need water pressure between 2 to 4 bar, if you use pressure above or below, it can affect the results on your finished wash. For low water pressure invest in an internal or external rinse booster pump.  For high pressure, you could purchase a restrictor valve to counteract.
  • The Water Regulations Advisory Scheme (WRAS) states that type A break tanks need to be fitted to dishwashers used in a commercial business and connected to the water mains supply.

For further information on Warewashing visit the Warewashing pages in the Catering Appliances section or contact the Alliance customer care team

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