Check out our online tech training courses at Master Samurai Tech…

Click here to check out our structured, online appliance repair training courses for rookies and experienced techs.

FAQs | Repair Videos | Academy | Newsletter | Podcast | Contact

Stay connected with us...

Samurai on Facebook - become a fan today! Sign up for our free newsletter and keep up with all things Appliantology. Subscribe to our YouTube channel for lots of appliance repair tips and help! Follow the Samurai on Twitter and get timely morsels of Appliantological Wisdom! Subscribe to our MST Radio podcast to learn secrets of the trade.

Samurai Appliance Repair Man's Blog

  • entries
  • comments
  • views

The Big Three Deadly Dishwasher Mistakes

Samurai Appliance Repair Man


Deadly Mistake Numero Uno: Using a gel detergent or powered detergent that is old or has already gotten wet.

The main tasks of a detergent are to remove soil from surfaces and prevent the re-deposits of soils on the surfaces. The best detergent formulations will be powdered. Do not use gels or liquid detergents.

Why powdered detergent? Because in today's phosphate-free world, you need two types of cleaners in a detergent formulation to get dishes clean:

1. Enzymes to remove protein-based stains

2. Bleach to remove other stains

These two cleaners are incompatible with each other-- if they're released at the same time, the bleach will destroy the enzyme and, after this epic battle, there will be little or nothing left of the bleach to do even its little bit of cleaning. The result: dirty dishes. They can coexist in a powdered form because they are not activated until 1) they get wet and 2) the water temperature reaches 125 deg. F. In a liquid or gel form, everything is already wet so you're only getting one kind of cleaning action.

Detergent has a shelf life. Old detergent will not work well because the enzymes denature over time. Also, the detergent must stay dry until it's time to use it. Once it gets wet or even damp, it activates and will no longer be active when put to work inside the dishwasher.

In my experience as a professional Appliantologist, my customers have enjoyed much better dishwashing results after I switched them over to Finish Powerball tablets. I leave two free samples behind and invariably, they report vastly improved washing results. BTW, I do not make a kickback for giving out the Finish Powerball samples-- I do it because the manufacturer, Reckitt Benckiser, puts on an excellent training seminar at the appliance training sessions I attend and it really does work well.

Deadly Mistake Numero Duo: Pre-rinsing dishes.

It is not only okay to put dirty dishes into a dishwasher, it is mandatory to properly activate the detergent! Detergents are designed to work with food soils, not clean water. Without the food soils, the detergent will create a caustic slurry inside the dishwasher which will etch the glassware by removing the silica from the glass.

Not only that, but pre-rinsing the dishes wastes water. DOE estimates that pre-rinsing dishes uses 20 gallons of water per load. Scrape the chunks off with a fork and leave the rest on the dishes. It's a dishwasher, for crying out loud! Let it do what it was designed to do!

Deadly Mistake Numero Trio: Not scraping the chunks of food or solid debris off the plates before loading them into the dishwasher.

Taken together, these last two Deadly Mistakes are a great illustration of the saying, "The opposite of dysfunction is dysfunction." People tend to fall into one camp or the other: they're either OCD pre-rinsers or they use the dishwasher as a garbage disposal.

You wouldn't believe some of the junk I've pulled out of dishwashers! Here's a short list of some of the things I've dredged up from deep within the bowels of broken dishwashers:

- plastic wrappers

- tooth picks

- bits of bone

- broken glass

- mayonnaise jar label

- an adult human tooth!

- crab leg shells

- candle wick holders

- ear rings

- a tongue stud-- yes, a tongue stud!

Today's dainty little dishwashers can't handle hard solids and these things end up damaging the innards of the dishwasher such as breaking the macerator or binding the wash motor impeller.

So there you have it, the Big Three. Almost every dishwasher service call I go out on, the customer is doing at least one of the Three Deadlies. But not you! Nawsir, not no more 'cuz the Samurai hath done enlightened yo ace.


Since you slogged (or scrolled) through to the end of this post, here are a couple of bonus tips for getting the best performance from your dishwasher:

Tip #1: Use Rinse Aid!

It’s not an option with today’s dinky dishwashers. Rinse aid allows the dishwasher to use less water with the same amount of cleaning and drying effectiveness. It does this by creating what we professional appliantologists call “sheeting action” of the water. By making the water sheet along dishes, rather than cluster into beads, it evaporates faster and with less energy.

Tip #2: Do Routine Dishwasher Tune-Ups

No tools needed! Regularly using a dishwasher cleaner (Affresh) and performance booster (Glass Magic) to clear out the gookus and reduce the build-up will keep your dishwasher clean and fresh smelling and operating at peak performance.


Kevin Vasconcellos


We have hard water in our neck of the woods & filming is a big problem. I've been tossing 4 or 5 salt tablets, the kind used in water softners, into the dishwasher before each load, along with detergent & using the longest, hottest cycle. The inside of my dishwasher is no longer getting the mineral buildup that it used to. Any thoughts on doing this?

Share this comment

Link to comment
Samurai Appliance Repair Man


Asko and Miele dishwashers actually do the same thing.  They even have a salt reservoir for this very purpose.  It's the same chemistry as the brining tanks used in household water softeners.  

Share this comment

Link to comment


Do you think it is important to tell the customer that incoming water temp should be above a certain temp?

I can remember being told detergent will not dissolve properly unless water is at 140 degrees.

That seems hot today. Most people have water heater set low to save money.

If I take a temp reading at sink and its 120 or below I try to get the customer to raise it.

Share this comment

Link to comment