How to Clean and Descale a Commercial Dishwasher

Advanced Chemical Solutions
July 26, 2022
5 min read

Adding steps to clean and delime your commercial dishwasher will not only increase performance but significantly extend the life of your equipment. 

Advanced Chemical Solutions is the leading regional chemical and service provider in Montana, Wyoming, Washington, Idaho, and South Dakota. We specialize directly in helping customers clean and maintain their warewashing equipment. We offer premium commercial detergents needed for cleaning dishwashers and the best limescale remover that we recommend every customer use. 

In this quick guide, we'll show you the steps we perform on every service call. As an ACS customer, you can expect this level of service on every visit. 

How to clean a commercial dishwasher?

The difference between a dishwasher lasting 10 years and 20 years is dependent on the amount of maintenance allocated to that machine. A machine that receives little care in a high volume establishment is lucky to have 7-10 years. With proper and regular cleaning and deliming, that same machine will last well into 15-20 years.
At ACS, we perform a thorough inspection of equipment and chemical performance on each service visit. If you are not an ACS customer, try incorporating these steps into a routine for better results.

1. Turn Off Power

To thoroughly clean and remove waste and removable parts, you will be required to reach into the machine. All commercial dishwashers run automatically when the doors close or with a button/switch; however, it is always good practice to reduce the risk of an accident by ensuring the power is off.

2. Drain the Machine

Drain the dishwasher and empty the tank. If your dishwasher is a high temp machine, we recommend leaving the doors open to allow the inside to cool down before removing any parts.

Drain Lever on a Hobart Dishwasher

3. Inspect and Clean Wash/Rinse Arms

Inspect the wash and rinse arms inside the machine. If there is excessive damage or continual rattling, it may be time to replace them. Clear the arms of any leftover food waste or other debris. Inspect the gaskets for wear as these could also limit the arms rotational performance. When removing the wash/rinse arms, place items aside to avoid losing small pieces.

Rinse Arm on a Hobart AM Dishwasher

4. Clean Interior

With a soft cloth or a light brush, clean the interior of the machine. Include the door guides and hard to reach corners. Scrape the debris into the scrap basket and use potable water or the spray nozzle to rinse the interior.

Employee washing the inside of a Hobart CLen Conveyor

5. Remove and Clean Screens and Baskets

Remove the screens, filters, or baskets and clean them in the sink with a brush and warm water. Be sure to gather any food waste in the sink and empty it into a trash can. This avoids a buildup of food waste in drains that can cause odor and damage pipes. We recommend establishments, especially restaurants use an enzymatic drain cleaner to keep drains clear.

Removable Basket from a Hobart Dishwasher

6. Reinstall Parts

After you have inspected and cleaned the removed parts, it is time to reinstall them where they belong. At this point, we suggest reapplying any Teflon Tape to parts that require it. Be sure to return all removable components such as screens, baskets, wash/rinse arms or drain balls to their correct positions.

Employee reinstalling a wash arm on a Hobart Undercounter

7. Run a Cleaning Cycle

When everything is back in place, and you have refilled the tank, our techs like to run a quick test cycle. We suggest this for two reasons when completing the cleaning process.

  1. It allows for additional cleaning to the interior with fresh water, premium detergent, and no debris.
  2. If any strange noises occur, our techs know to double-check all parts are in their correct position.
Employee performing a washing cycle on a Hobart Dishwasher

8. Leave Doors Open

If this is the end of the shift or the end of the day, be sure to leave the machine door open and remove any curtains. Drain the tank if it is the end of the day. Allow the interior of the machine to dry. This will decrease the growth of bacteria in your machine.

Hobart undercounter dishwasher display
above images Copyright ITWEFG


For many establishments, hard water is a common problem that causes a limescale buildup on machines such as Dishwashers and Steamers. Installing a water softener is a great way to filter minerals such as magnesium and calcium.
Using a premium limescale remover for maintenance will help your machine operate at optimal levels. When a dishwasher has excessive amounts of mineral buildup around heating elements, door guides, or clogging wash/rinse arms, you may notice the following.

  1. Wash/rinse Arms can loosen, causing them to rattle and shake.
  2. Wash/Rinse Arms can become clogged, not allowing water to pass through.
  3. Electrical issues can compromise your machine's efficiency.
  4. Overuse and over-reliance on detergent to get clean results.

Follow these quick steps to create a comprehensive maintenance routine.

Heating Element with Lime Scale Build Up

1. Safety First

Deliming a commercial dishwasher is helpful for equipment performance, however not required for daily care. Having the right safety gear and detailed instructions will help employees properly perform this level of care. Gear such as heavy-duty latex gloves, eyewear, masks, and protective clothing will greatly assist employees.

2. Follow Delime Cycle Settings

Most commercial dishwashers will have settings intended for what is called a Delime Cycle. Make sure to adhere to the settings and follow instructions given by the manufacture.

Hobart Dishwasher Display Settings

3.Use a Premium Lime Remover

ACS provides customers with a Premium Concentrated Delimer call Lime Free. We use this product ourselves when refurbishing equipment with large amounts of mineral deposits. It works great for large jobs and regular maintenance. Introduce Lime Free into the machine at an amount instructed on the label. Be sure to run a cycle to allow Lime Free to work. Continue until satisfied with removal.

Lime Free Premium Lime Scale Remover

4. Clean The Exterior

If this is a refurbishing project or a deep clean, dilute Lime Free, according to ACS instructions, in a 32 oz. Spray-bottle to clean outside areas. Remember to wear protective gear and ensure adequate ventilation. Rinse and clean surfaces and repeat until satisfied.

Lime Free Spray Bottle

5. Inspect Dishwasher

Inspect the dishwasher after the delime cycle. Repeat step 3 until the mineral buildup is gone. When satisfied, drain the tank and refill it with fresh water. Run another cycle to rinse and remove any remaining Lime Free.

Service before the sale

Depending on machine condition, an ACS customer can expect a similar level of maintenance upon every service visit. It is this level of customer care that makes ACS your local choice for service and products.

Contact ACS for more information on our chemical programs, service solutions, machine rental agreements, and partnerships. Take action today for better service!