Secrets to Make your Dishwasher Clean Perfectly

December 20,2004

As a service company we are constantly asked, “Why doesn’t my dishwasher clean better”. To this query we offer the following insights and suggestions.

Whenever we diagnose a “poor cleaning” complaint the main things we want to know are:

1 Is the water hot enough?
2 Using a proper detergent?
3 Using a rinse additive?
4 Using proper loading practices?


1 Water temperature

Most manufacturers suggest a minimum 120 Fahrenheit for the dishwasher to begin the cleaning process, 140 to remove food soiling, and 155 to sanitize and remove bacteria. In restaurants they boost the dishwasher temperature to 180 Fahrenheit to satisfy health requirements. Consumers misunderstanding these requirements have led to problems for the household dishwasher.

In a dishwasher the temperature of the wash water is paramount. Unfortunately, It is now common to find household water temperatures of only 100 Fahrenheit, or less.

Many people have lowered their household water temperature in an effort to be conscientious consumers. Yes, it lowers electrical consumption. Unfortunately it has other consequences.

Manufacturers say it does not provide enough heat to clean dishes properly and can leave them covered in bacteria and food residue. Supporters of lower water temperatures claim it is both environmentally friendly and necessary to protect children from any possibility of scalding at bath time.

One of the latest ideas is a mixing valve added to hot water tanks. It is preset and will not allow temperatures in excess of 115 Fahrenheit. It does this by mixing cold water with the hot to maintain this preset maximum.

This debate over hot water tank temperatures has resulted in a catch 22 type scenario. Lower the temperature to lower consumption and be more child safe, but end up leaving bacteria on the plates we use to eat.

Low water temperature can also affect the cycle length. If too low the dishwasher may keep stopping to try and heat the water. A normal cycle of 40 minutes could be extended to 2 or 3 hours with all the heating delays. Some dishwashers may stall completely.

2 Using proper detergent

Gel or crystal, the choice is yours. Both seem to work equally well.

Crystal is less messy, while gel will dissolve quicker with the water. If your water temperature is low (as described above) gel may be a choice because it will mix better.

If using crystal detergent be aware that it can pick up moisture from the air. When this happens it will swell up and become lumpy or harden. These lumps will be difficult to break down and will not fully dissolve. If at cycle’s end you see detergent left inside it may be evidence of hardened crystals.

Additional evidence of moisture buildup can be seen if the box itself appears to be swollen. If seen, replace immediately with a fresh box.

A box of detergent should be consumed within 2-3 months. If not throw it away and buy a new one. Match the box size to your needs. Do not buy a large box just because it is on sale. If you have to throw most of it away, it wasn’t much of a bargain.

Some detergent manufacturers now offer a product that combines the detergent with the rinse additive. Others offer a detergent that includes a special grease-dissolving agent. Still others are in a tab form, or inside a dissolvable plastic pouch. Whichever form you prefer the one thing we always stress is, “when you find one that works for you stick with it … even if it costs more than others”.

Also dishwashing detergent and dishwasher detergent are not interchangeable. Trying to do so will cause problems. Each type of detergent is formulated to do a specific job.

“Dishwashing detergent” is the one used to wash dishes in the sink is. It is definitely not meant for the dishwasher. Anyone who has ever mistakenly put it into the dishwasher can attest to the mess this will produce. The beating action of the water will produce massive amounts of suds. This results in the dishwasher flooding out the door and across the kitchen floor.

So the moral of this tale is: “Don’t confuse dishwashing with dishwasher”.

3 Rinse additive

This is something that gets forgotten once the free sample bottle that came with the dishwasher has been used.

Its job is to make the water run off the dishes faster so they can dry quicker. Without it there would be little beads of water on everything at the end of the cycle. Glasses especially would appear to be water stained or be left with a gritty residue.So if poor cleaning is a problem, check the rinse additive level.

But remember, only one or two drops are added per load. A few ounces of rinse additive lasts a very long time. Such a long time that customers often think it is not being added, and blame the additive for problems it has nothing to do with

To refill, look on the dishwasher door for a cap or plug that is removable. It is often overlooked because the time between fill ups can be months. Also, the appliance manufacturers could help solve this problem if more of them added some sort of “Hey, I’m empty” indicator.

Frigidaire dishwashers have a neat little indicator. Right next to the soap dispenser is a clear plastic eye that changes colour when the additive is empty. So every time you add detergent to the machine you also see this eye staring back at you. White if empty, and black if full. Simple, effective, and smart.

4 Proper loading

Lastly, don’t forget that how you load the dishes can drastically affect how well they are cleaned.

Proper loading will allow the water to penetrate all the nooks and crannies. Try the following suggestions:

·Cups and glasses on the top rack with bottoms up
·Plates on the bottom rack all facing the same direction
·Bowls either rack, but all facing the same direction
·Utensils in the utensil holder in a mixed fashion (some knives, forks, spoons together in each compartment) to allow gaps between them
·Large items, such as a spatulas, laying down on top rack
·Pots bottom up wherever space allows (on their side okay if positioned so that water will drain out)

Placing the dishes and utensils in an orderly manner really does make for a better wash. It allows the water sprays to penetrate the dishes thoroughly. Try it … it works.

The analogy I offer customers is: If you were going on a car trip would you pack the car efficiently, or just open the doors and throw everything inside so that the passengers had to fight with the luggage. I think you get the picture.

Dishwasher efficiency

If your dishwasher is having a mechanical problem the result may show up as poor cleaning. Anything from low water pressure, broken pump, not draining fully, or even a blocked filter could be the cause.

So how do you know if the machine needs repair? You don’t. But, by checking all the previous problems first a lot of the more common causes of poor cleaning can be easily eliminated.

Also, you have probably heard this a million times before, but before telephoning for service read you owner’s manual. It can include some valuable information. It will usually give you a checklist of items to test before calling for service.

Summing up

You now know what is needed to make the dishes come out of the dishwasher sparkling clean. Hot water, good detergent, rinse additive, and proper loading practices. That’s it – that’s all. Provide all four of these things to the dishwasher and your cleaning success is guaranteed.

So load up the machine, go get yourself a liquid refreshment, put your feet up and let the dishwasher do all the work.