Imagine trying to hand wash dishes with cold water – what a nightmare! Anyone with experience in washing dirty dishes will know how effective hot water is at softening and loosening stuck-on foods.
Without hot water you’d need a hammer and chisel to remove things like encrusted Corn Flakes inside bowls, dried in sticky sauces on plates, and don’t get me started on burnt frying pans.
The great thing about dishwasher is they’re able to wash dishes with water way hotter than we could handle with our hands. They use hot water over 60°C and steam to melt away the toughest of caked on stains, with ease.
But like every appliance, they can develop faults like not being able to heat the water. If you’ve noticed that you dishes are cold and still dirty (and dripping wet) after a washing cycle, then this is a tell-tale sign that your dishwasher has stopped heating water.
You could be faced with two scenarios:
- Dishwasher still heats water, but not hot enough
- Dishwasher no longer heats up at all, water is cold
Depending on the heating output of your machine, other causes for the problem may be possible. In the event of a total failure of the heating power, the heating element is often to blame, which will require professional repair.
Let’s walk through some possible causes and solutions for a dishwasher that won’t heat up.
Causes of Poor Heating Performance
If water is look warm or cold, you’re looking at problems in the area of the water inlet or the heating elements. These no longer work properly and therefore have problems heating the water. These problems are sometimes small and fairly simple to fix, and include;
- Calcified heating element
- Wrong water pressure
- Heating element damaged
With the exception of the vacuum switch, pressurized can, and heating element, these problems can be solved quite easily and help to be able to use the dishwasher effectively again. It is important that you carry out these checks carefully to source the issue before calling for help.
Dishwasher need heat to not only soften and wash dirt from dishes, but to dissolve dishwasher tablets and salts. Fat, oils, and cooking grease will not dissolve and drain away properly, instead, will block pile and damage internals.
Limescale on Heating Element
If you live in a very hard water area and you fail to use dishwasher salt, the heating element can become calcified in limescale over time.
Unless you like in a soft water area like a lot of Scotland, your dishwasher needs a certain amount of descaler and dishwasher specific salts, as the amount of agent in tabs is not enough to efficiently soften the water. Each machine has a salt indicator, either two intertwined arrows shaped like an S or a cup with an S on it, which indicates when the salt needs to be refilled. If this is not done, one of the most common problems is that the heating element is calcified and can no longer heat water efficiently.
How to descale a heating element:
- Switch off the dishwasher at the mains power (double check)
- Remove all dishes from the dishwasher
- Place a reputable dishwasher descaler into the machine
- Select a program very hot heat (60°C min)
- Do not select a pre-wash program
- Run the cycle and let the descaler work its magic
By doing this, the dishwasher the agents should be able to remove the limescale encrusted over the heating element. Since the heating element is not exposed in modern machines and can only be reached with the necessary technical knowledge. Fingers crossed, the machine should improve water heating again. If not, let’s check the water inlet.
Dishwasher Heating Toubleshooting
When it comes to the dishwasher, it is particularly important that the amount of water supplied is correct. This can be influenced by a variety of causes, including:
- The mains valve is restricting pressure
- Calcified inlet hose
- Kinked water hose
- Blocked hose
- Leak somewhere in the inlet
Turn the tap in completely, then adjust the mains water value to see if water pressure increases. As a precaution, place a bucket under it and try to turn the tap on completely. If there is a steady flow is water pressure coming from the mains supply then you’re good to do. If only a stickle of water comes out of the tap, it is either calcified or there is a problem with the general mains water supply in the house. To clean a limescale blocked water supply to the dishwasher hose, do the following:
- Unscrew the hose
- Clean all connection points
- Use a descaling cleaner if necessary
- Put everything back together and hopefully water pressure is restored
At this point, water should properly passed back to the dishwasher and the appliance has enough water to heat.
Next, check all the hoses for kinks of leaks. How to solve possible kinks in hoses without having to dismantle them:
- Pull out the dishwasher
- Inspect hose from mains to dishwasher inlet
- Straighten any kinks
- If you find a leak, replace the hose
If no heating output is noticeable after the above checks and the water remains cold, there are completely different problems that relate purely to the technology of the machine. The dishwasher has a large number of components that can only be replaced, repaired or recalibrated with the necessary specialist knowledge.
The following internal components need to be checked, repaired or replaced by a specialist technician:
- Heating element
- Power supply lines to heating element
- Circulation pump
- Electronic switches
- Relay control
It can often happen that no component is actually damaged, but incorrectly calibrated. The sensors and the thermostat inside the dishwasher ensure the correct dosage of detergent, water and heat. As soon as they no longer calculate the right performance for whatever reason, the dishes remain cold and dirty. If you have tried the above and the dishwasher is still doing a cold wash, you should make a claim under your warranty or contact a technician to have a look at your machine.
I’ve had my dishwasher fail to heat water once, and when checked by a professional it was found that the internal heating element was broken, and I was told that this is the number one fault when dishwasher stop heating water, so it’s always best to get someone with expert knowledge and the right tools.