There are lots of things that can cause water spots on the dishes at the end of wash.
Note, however, that there are a few things that are prone to spotting even if your dishwasher is operating perfectly.
Teflon™, for example, has a relatively porous surface that holds water, then sort of oozes it back out later. It is difficult to air dry and it usually must be wiped with a towel.
Certain kinds of plastic have similar issues.
Which of the following best describes your wash quality problems?
When the wash starts, there cannot be any cold water left in the tub from the last wash.
So every wash begins with a drain cycle, to clear out any cold water from the tub.
We need to know if the tub is draining at the beginning and end of the wash.
Stick a finger in the lowest point of the tub that you can reach. There should be no water there. At the very most, there might be enough to barely wet your fingertips.
The discoloration of clear glass is known as acid etching. Etching of your glassware is damage of a more permanent nature. In early stages, the glassware may have an iridescent blue, pink or purplish look when you hold it under the light in a certain way. In later stages, the glass takes on a cloudy or milky appearance, or it may even be pitted. This cloudiness or milkiness cannot be removed by any amount of scrubbing. This later stage should not be confused with filming, which can be removed by a little Lime-Away™, Glass Magic™ or white vinegar.
Etching is caused by overly acidic conditions inside your dishwasher. It does not seem to be related to the cost or quality of the glass. Soft water tends to be acidic to begin with. Soft water at excessively high temperature and in combination with lots of detergent seems to be the conditions most conducive to acid etching.
Blackening, graying, bluing, or tarnishing of silverware is caused by the same excessively acidic conditions.
Discoloration of metal utensils, pots or pans can also be caused by mixing dissimilar metals in your dishwasher. Stainless steel, aluminum, silver, copper and cast iron should not be washed together.
Likewise, fine china can be blackened by chemical reactions between metal and the detergent or rinse agent.
Acidic conditions in your dishwasher are caused either by excessively "soft" (acidic) water, or by using the wrong detergent or rinse agent.
Is the water at least 140 degrees F?
It is CRITICAL to have wash and rinse water at around 150 degrees, plus or minus ten degrees. Any cooler, and the detergent will not dissolve properly, resulting in spotting or filming. If the dishwasher has a heater, the fill water may be just a little cooler, as low as 125, but it should be at least 140 well before the end of each cycle. The heater is not designed to heat cold water; it is designed to maintain water temperature.
All the appliances in your house that use water have (or SHOULD have) anti-siphon protection.
Waste water from your dishwasher drains to a sewer system. If water fills the drain hose completely, with no place for air to enter the drain, it IS possible for effluent to siphon from the sewer back into your dishwasher. Yuck, right? Doesn't happen often, but it HAS happened.
To prevent this, your dishwasher has an anti-siphon device called an AIR GAP, installed in the drain hose.
It is required by law in most installations. It prevents accidental backflow (siphoning) into the dishwasher from the house drain lines.
A typical air gap re-directs water 180 degrees, and thus it has constrictions that can easily trap a chunk of food trying to pass through it.
Symptoms are the same as for any other blockage of the drain line, except that you may also see water flowing out of the air gap vents directly onto the countertop or into the sink.
Fortunately, they are pretty easy to open and clean. In most installations, it is a little chrome or brass blob with a couple of vent holes in it, sitting right next to your sink faucet handles. If it's not there, find the hose that drains your dishwasher into the sink trap or garbage disposal, and trace it back directly to the air gap.
Usually all that's involved in cleaning it is to pull off the little chrome blob and unscrew the top of the air gap itself. Both drain pipes will be exposed. Often you will find a seed or broken glass, or other bits of food wedged in there.
If you have a garbage disposal, unplug it. Remove the dishwasher drain hose from the garbage disposal, or from your house's plumbing, and poke a short screwdriver through there to see if it's blocked by anything.
Also try blowing into the hose; you should hear air bubbling back into the dishwasher pretty vigorously, and there should not be a lot of back pressure. If not, it's blocked, or partially blocked. Remove it and clear it.
Don't forget to plug your garbage disposal back in TO THE SAME SOCKET IT CAME OUT OF!
About the worst case of water temperature problems I ever saw was caused by a kinked hose in an improper installation. The complaint was water spots on the dishes. Whomever installed the dishwasher had left too much rubber drain hose connected, and when the dishwasher was pushed back into place beneath the counter, the drain hose kinked badly.
The old, cold water would never drain out of the tub at the beginning of the cycle, and thus it would not fill with new hot water. (The anti-flood float switch would prevent overfill.)
Incidentally, it had been installed two years before, and the people had been trying to use it regularly since then.
Thus, in addition to that two-year-old cold water in the bottom of the tub, there was also two years' worth of detergent and disgusting, moldy leftovers. The solution was to simply cut the drain hose shorter, but I have no idea how many cycles it took to melt all that gunk out of the tub. I also have no idea why it took them two years to call me.
To test the temperature, Turn a heavy glass upright and wedge it into place so it will collect water, and put a candy thermometer into it. Let it run in the wash cycle for at least five minutes, then open the door and see what the temperature is.
If the dishwasher is installed right next to the kitchen sink, as it is in most installations, you can run water out the sink and test the temperature there.
If you do, however, take note of how long the sink faucet runs cold before hot water starts running out. And try to note how many gallons of cold water this amounts to. That's roughly how many gallons of cold water that are entering your dishwasher before any hot water gets there. That itself can cause a "cold water" problem...if your water heater is mounted too far away from your dishwasher
Cold Water does not seem to be the problem with your dishwasher.
Click Here to try another diagnosis for your dishwasher's symptoms.
If your water temperature is too cool, you have several options, depending on the cause.
You can try turning up the water heater temperature; sometimes this is enough.
But to my experience, water fill temperature problems are usually caused by the dishwasher being installed too far away from the water heater. The tub fills with only a gallon or two of water; by the time the hot water gets from the heater to the dishwasher, the tub is at least half full of cold water.
If the dishwasher water feed tube comes off the same line that feeds the sink, it may help to warm up the line by running water out the hot water sink faucet before starting the dishwasher. However, the hot water line may cool off again between the wash and rinse cycles, so you may need to leave the sink valve cracked open a little to keep the line warm. This wastes a tremendous amount of water.
It's a tough problem, and solving it can involve re-designing the entire water system in your house.
Before you do that, you might consider installing a small instant water heater nearer to the dishwasher. There are several small heaters available that heat just a few gallons and are made to be installed beneath the sink. Ask your appliance parts dealer or check your local hardware store.
I could never understand why some people are so fixated on NOT having to pre-rinse...being able put chunks of food in their dishwasher. Your dishwasher is NOT a garbage disposal. It IS engineered to be able to ingest small bits of soft food left on dishes, but it is NOT made to ingest big wads of dried-out, moldy leftovers. How hard is it to scrape a few food scraps into the trash? Ultimately, your dishwasher will treat YOU as well as you treat IT.
Click here for an interesting video on the subject.
So when you put the dishes in, scrape any chunks of solid food into the trash, and rinse off any moist food before it gets dried on.
If it's dried already, you are risking that the dish will not come clean. Wiser to take a minute and scrub it off.
Also remove any vegetables, fat trimmings from meat, chicken or fish skin, and even smaller items like seeds and toothpicks.
Let's put it this way; you can take the food off the plate now, or you can clean the wet, nasty, chopped-up food out of the dishwasher's water filter later. Your choice.
Also remove any excessive amounts of oil or grease. They can congeal and clog up the spray arm holes and drain system.
Some people re-use glass jars from grocery store food. That's fine, but you MUST REMOVE THE LABEL before you put it in the dishwasher. Any paper that comes off will end up as mush, and clog the water filters and spray arm holes in your dishwasher.
Loading the dishwasher improperly can cause all sorts of problems, from blockage of the waterspray to dish or pump damage. Make sure the dishes are loaded properly.
After loading, make sure that the wash arms will rotate freely. Also, make sure that loaded dishes do not block the opening of any detergent or rinse agent dispensers.
Plates go on the bottom rack, on edge, so the wash water drains. Small plates (like saucers) go on the top rack with the glasses and cups.
HAND WASH hand-painted china. The high-pressure hot water jets inside your dishwasher may be enough to wash the hand painting off. Wine glasses and other stemware, and antique or very delicate crystal or china can break easily under high temperatures and pressures.
Also HAND WASH lacquerware, genuine antique milkglass, or aluminum. These items may discolor.
Stainless steel utensils should go handle down, except for knives, which go handle up, so you don't cut yourself. You should mix knives and forks and spoons in each compartment to help prevent them "nesting." (Don't let your spoons spoon!)
Cutlery with wood, bone or horn handles may crack or break or split under high temperatures and/or hydraulic pressure. You should hand-wash these.
Aluminum, stainless steel, copper, and silver-plated items must NOT TOUCH each other...it can cause darkening of the silver or corrosion between the different metals. Iron skillets or pans must be HAND-WASHED...they rust. Any rust that comes off is also very abrasive and will not be good for the pump and seals.
Pots and pans go on the bottom rack, with the dirty side down.
Cups and glasses go on the top rack, open end down, between the prongs sticking up. They are there to help keep the cups and glasses from rattling around. Glasses with concave bottoms should be angled, so water doesn't pool on them.
Anything plastic goes on the top rack. IF plastic items come near to or touch the heater, at the bottom of the tub, they could warp or melt.
It's important to know that washing dishes in a dishwasher is not just a matter of blowing hot water at them. It is not just simply a mechanical or hydraulic process. It is also a CHEMICAL process. The chemicals you use, from detergent to rinse agent, are extremely critical.
You get what you pay for. Use acidic or hard detergent, and you will have problems and you will shorten the life of your machine significantly.
In early stages, the cheap stuff may just leave a lot of water-spotting, filming and calcium build-up. Long-term, it can cause acid-etching, clogging of water passages, and abrasion of dishes and the internal parts of the dishwasher.
I know you probably don't want to hear it; you want to save the money. But when it comes to dishwashers it's ESPECIALLY true; even more so than with other machines. It doesn't pay to cut corners on what you put into your dishwasher. You can save a few pennies now, but it will cost you dollars later. What I call penny-wise, and dollar-dumb.
Here's the scoop: Use dry (powder) Cascade™. The real stuff. Do not use liquid detergent. In my opinion, they have not yet figured out how to make liquid detergent that dissolves properly. And especially do not use regular liquid dishsoap. It is made to suds up, which you do not want in a dishwasher.
Also use "Jet-Dry"™ and check it regularly. "Jet-Dry"™ causes water to sheet and run off the dishes, instead of beading up and spotting them.
Also use a product called "Glass Magic"™ regularly to assist in preventing filming or etching of the glass surfaces. Put a mixture of about 1/3 Glass Magic™ to about 2/3 powdered Cascade™ in the pop-open door dispenser. This will open and dispense the mixture during the second wash cycle.
Calcium buildup and acidity do not just affect how your dishes look. Look, if acid is eating and calcium is abrading the glass in your dishes, what do you think those chemicals are doing to the working parts of your machine, under high-temperature and high-pressure conditions?
Detergent and rinse dispensers are simple devices. You apply electricity to them, and they release the dispenser door or cover.
I'm not going to bore you with how they work, but if you're a gadget person and need to know, they are usually wax motors, bimetals, or solenoids.
If dispensers are not popping open, either the mechanism has failed, or it is gunked up with detergent or rinse agent.
Remove the dishwasher door panel to access the inoperative dispenser. Remove it and clean it out thoroughly. If it still doesn't work, replace it.
If you wish, you can test them for continuity with a multimeter. If you don't have a multimeter or know how to use one, click here.
Many dishwashers have a drying cycle. The dryer may be the same internal heater as the water heater, or it may have a blower fan.
On some machines, the blower fan assembly is mounted inside the door panel. In others, it is mounted on the side of the dishwasher, and you must remove the dishwasher from under the countertop to get to it.
Excessive spotting may mean the dryer blower or heater is not working. Test the motor or heater and replace if defective.
If your water supply is excessively soft, it is a tough problem to solve, but there may be few things you can do about it.
If you have a water softener, you might try "turning it down" somewhat, so the water is not quite so acidic.
If you are experiencing soft water problems, have it tested by a water expert. He or she may have some suggestions as to what to do about it locally.
You may also want to test the pH of the detergent or rinse agent you're using.
If you have soft water, and you can't do anything about it, make sure it is entering the dishwasher at a temperature below 150 degrees. Also try cutting the amount of detergent you use in half. (Make sure the dishes are still being cleaned and sterilized, of course!) Realize, however, that some types of glass seem to be prone to acid etching no matter what you do.
Small water jets in the spray arms can be clogged by bits of food, seeds, or glass from broken dishes that have gotten by the pump suction filter screen, preventing them from spraying a hard stream at the dishes.
Small holes in the pump suction screen or spray arms can become clogged by hard water calcium buildup or bits of food or broken glass, preventing the pump from getting enough water and putting out enough pressure.
Remove the pump suction screen from the bottom of the tub and examine it for white calcium buildup or food particles that might be clogging it. Rinse out any debris. If you're not sure how to do this, click here.
Remove the spray arm assembly and shake it. Any bits of glass or other debris will make a noisy clatter. Try to remove them. It can be difficult; it's a lot like trying to fish coins out of a piggy bank. Try putting tape over the holes in the spray arm, then partially fill it with water, then shake the water out...most of the broken bits of debris should come out with the water. If it's too hard, just replace the spray arm.
If you have a calcium hard water buildup clogging any water holes, run a cycle with no dishes and some Lime-Away™, CLR™ or white vinegar. It should clear up the holes.
If the holes are just too badly clogged, replace the filter or spray arm.
This usually shows up as poor wash quality (severe spotting) due to cold water. Usually something is clogging the drain line or the Air Gap.
In GE or Kitchenaid machines, the drain valve solenoid may not be operating. Check the solenoid and also the timer (which controls it) as described in sections 6-2(a) and (b).
Another possibility is that junk has gotten into the drain pump impeller, and the vanes are broken clean off. Disassemble the pump as described in Chapter 5 and check the impeller.
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