Why Your Dishwasher Isn’t Washing with Hot Water

Paradise Appliance
January 14, 2021
Dishwasher Repair

The dishwasher uses a combination of techniques to clean your dishes. After all, it needs to clean a variety of dishes. Cookpots, dinner plates, silverware, and plastic Tupperware are all cleaned in the same washing cabinet. The dishwasher uses soap and water pressure and, of course, heat. Every dishwasher uses hot water to clean the dishes. Even if you turn down the heat, warm water is still essential for breaking down food and minimizing the water residue left behind. The hotter the water, the better it cleans.

However, sometimes a dishwasher may become unable to use hot water. In this case, the quality of dish cleanliness will go down over time. The cause of missing hot water varies depending on the type of dishwasher you have. In fact, how a dishwasher handles hot water is one of the biggest differences between the types and models. Some heat their own water with electric heating elements, some pull hot water from your water heater. 

Signs Your Dishwasher Isn’t Using Hot Water

The first step is to identify what is wrong with your dishwasher. Usually, we do this by the symptoms we notice in the dishes themselves. If your dishes are not coming out fully clean, the manner of that uncleanliness will tell you what’s wrong. Hard water, for example, can be detected in round dusty water spots that appear after the drying cycle. Likewise, a lack of hot water can be seen when food is not fully washed away or dissolved during the washing cycle.

Food Still Crusted on Dishes

Look for signs of food still crusted on surfaces and especially in corners. The dishwasher sprayers must reach inside the dish, but the water must also be hot enough to dissolve every thing it touches. Without hot water, food may remain unwashed from your dish surfaces and inner rims.

A similar sign is a crust still left on your silverware. If your silverware has washed clean in the past, watch out when many utensils do not come out clean. Of course, some things like dried cheese are stubborn, but if most of your silverware does not wash clean, this is a sign of water not hot enough to dissolve.

Dishwasher Detergent Residue

Dishwasher detergent is heavier than normal dish soap. It’s meant to wash thoroughly without sudsing too much inside the dishwasher. But it also takes some pretty hot water and strong water pressure to wash fully away. If your water pressure is weak or your water isn’t hot enough, there may still be detergent left on the dishes and inside of the dishwasher compartment.

Look for signs of detergent and soapy residue on your dishes when investigating a problem with dishwasher water heat. 

Possible Solutions to No Hot Water in Dishwasher

Once you’re reasonably sure that hot water is the issue, start looking into the possible causes. Depending on the type of dishwasher design you have, there are four possible sources for a lack of hot water during the washing or rinse cycle. There are two different designs for heating elements that heat water already in the dishwasher. Alternately, there are dishwashers that use hot water from your water heater. Your dishwasher may also be misjudging when to create or dispense hot water.

1. Basin Heating Element

Many dishwashers have a heating element that rings tubs in the dishwasher floor. This tub gathers water, heats it, and then pumps the water back through the dishwasher to continue washing the dishes. This method relies on an exposed heating element, the kind notorious for melting fallen plastics. If that heating element stops working – possibly because the plastic was melted onto it, then water can’t be heated in the dishwasher.

To repair, the most practical approach is to replace the heating element. Electric heating elements are not expensive and they are more reliable new than they are possible to repair once damaged.

2. Flow-Through Heating Element

A flow-through heating element is a design that masks the element from open exposure. Instead of heating a pool of water, the water is heated en-route as it flows through channels inside the dishwasher. If this is broken, you will need to open the lower housing to access and replace it. The flow-through element is safer but also more protected when it comes to maintenance.

3. Hot Water Line

Dishwashers that do not have a heating element draw hot water from the household hot water line instead. This drains the water heater, causing it to refill and heat new water. In other words, these dishwashers use the water heater’s element instead of their own. But this does make them reliant on a working hot water line. If this line is clogged. closed, or if the water heater fails then your dishes will not be cleaned with hot water.

4. Internal Dishwasher Thermostat or Timer

Lastly, it’s possible that your dishwasher doesn’t know that the water should be hot. Its internal thermostat is supposed to indicate when in the wash cycle to heat or provide hot water. If the timer is wrong or if the thermostat reads incorrectly, the washer may not provide hot water even if it is capable.

You will need a technician to check whether your dishwasher thermostat is working correctly, or if the trouble lies with your control timer instead. An experienced technician can open the dishwasher housing and test each component with a multimeter so they know which one to replace. 

Repairing Your Dishwasher for Clean Dishes

If your dishwasher has recently become inept at cleaning dishes, this can be fixed. Every element of dish cleaning comes down to basic functions inside the appliance. With the help of an appliance repair technician and the right replacement parts, your dishwasher can be heating water correctly and washing your dishes completely in no time.

Whether you are looking to learn how to DIY repair the dishwasher for yourself or need a quick solution to an inconvenient problem, we can help. Contact us today to consult on the performance of your dishwasher and how we can help to enact the necessary repairs.


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