Dishwasher not heating or drying, faulty heating element or Thermostat

If your Dishwasher water is not heating up during the washing cycle!

Then you might have a heating fault or thermostat failure the dishwasher cycle settings vary from 30 degrees Celsius to 65. However, the water is staying cold through the whole cycle. Grease and grime are starting to build up and food-based products are not cleaning from dishes properly. This is normally a problem with the heater system or thermostats see our video to help you on this.

Dishwasher Heaters and Thermostats

You’ll notice a couple of symptoms which make it easy to spot if your dishwasher isn’t heating up the water properly – at the end of a wash program your dishes won’t be clean, and they won’t be dry ( NO Heat). Lack of hot water can be caused by a few different reasons and the problem is also dependent on your dishwasher model. But a simple hack is put the dishwasher on a hot cycle and record the high and low temperature with a thermostat or a recording device like our testing system.

Error Codes

On digital displays you may get a fault code displaying telling you the fault with the dishwasher.

But on non-digital displays you may only get a flashing light or a sequence of flashing lights which is very hard to work out unless you have the manufactures workshop manual.

Heating Element

Regardless of whether it’s plumbed into a hot or cold water supply, your dishwasher will have a heating element (visible in the tub) or a flow-through heater (which under the machine usually) that are used to control the water temperature and aid in the drying process.

Although the heating element is generally a very reliable component of a dishwasher, it can burn out or suffer from an electrical/wiring fault.

If you have a multi-meter you can measure the resistance of your heating element which should read somewhere between 15 and 35 ohms Depending on element size fitted by the manufacture. A reading above 40 ohms would mean you either have an element below 1500 watt or it means the element is faulty and will need to be replaced. If the resistance reading is OK then check the wiring and control board for damage.

Check ohms law with the size of the element fitted and the voltage of your appliance.

On a 240 volt system

Example

1800 watt element should read 32 ohms (Ω) this will be pulling 7.5 amps when on

2000 watt element should read 28.8 ohms (Ω) this will be pulling 8.3 amps when on

A replacement heating element isn’t massively expensive, and if you’re comfortable getting your hands dirty then it’s fairly simple to replace the part with a basic toolset and our video.

Thermostat

The thermostats are the other component that can commonly cause your dishwasher to not heat the water. The job of the thermostat is to regulate the water temperature throughout a wash program. If it’s faulty then the dishwasher won’t “know” when to turn the heating element on and off to keep the water at the required temperature. there is normally a thermal cut out protector/thermal cut-out when this goes above temperature then it goes open circuit and can’t be reset.

Just like the heating element, you can test the thermostat using a multi-meter to determine whether or not it is the source of the fault. Luckily it’s a very cheap part if you need to replace it, the only real difficulty is getting access to it as you’ll find it underneath the dishwasher. On flow through heaters they normally can’t be changed.

Other faults that can be causing this are:

The wiring may have gone faulty check the wiring back to the program especially around the door area.

The relay switches on the printed circuit board (PCB) may have become faulty.

You may have a faulty NTC sensor not reading the correct resistance at temperature.

All these tutorials are available at our site.

You can always attach a multi meter to the element and see if power goes to the element when on heating cycle, or you can try a continuity test on the thermostats and heating element.