Dishwasher Not Heating Up? (here’s why & what to do)

If your dishes are not getting properly clean in the dishwasher, the most likely cause is the water isn’t getting hot enough. Cold water isn’t as effective in removing dirt, grease and food as hot water. Which is why your dishes are still dirty (to some degree) even after they have been washed in the dishwasher.

In this article we look at all of the possible reasons why your dishwasher might not be heating up and offer solutions on how to get it working properly again.

Why Is The Dishwasher Not Heating Up?

There are a number of things that could cause a dishwasher to not heat up which include;

Probable Cause	Solution
Incorrectly fitted drain hose	Adjust the drain hose to the correct depth in the standpipe
Clogged drain filter	Clean the filter
Defective heating element	Replace the heating element
Defective thermostat	Replace the thermostat
Defective pressure switch	Replace the pressure switch
Blocked compression chamber	Contact a technician
Damaged electrical wires	Contact a technician
Defective PCB	Contact a technician

Incorrectly Fitted Drain Hose

The problem could be caused because the dishwasher’s water is continuously being drained away or syphoned because the drain hose is fitted incorrectly. If the drain hose on the dishwasher is inserted into the standpipe too far, the water will drain from the appliance almost immediately.

The water will flow into the dishwasher before being syphoned out almost at the same time. This would cause the water to keep flowing for too long which would cause the dishwasher to enter fault mode and cancel the cycle without displaying an error code or heating the water.

To solve this, reposition the drain hose and fix it in place using the bracket that was supplied with your appliance. The drain hose should not be inserted into the standpipe any more than 10cm (4 inches) and the standpipe should be at least 65cm (25 inches) above the ground level.

Clogged Drain Filter

The drain filter is designed to trap any food particles or debris and prevent them from getting back onto the dishes. If the filter is extremely dirty or clogged, it reduces the motor’s suction. This could affect the dishwasher’s ability to heat up.

You will need to remove the filter and wash it in warm soapy water. Any stubborn dirt or grease can be removed using a toothbrush. If the filter is really dirty, it can be soaked in a solution of white vinegar and water.

Once the filter is clean it should be replaced in its housing and the dishwasher should function normally again. You will need to get into the habit of cleaning the filter at least once a month from now on to prevent this problem from recurring.

Defective Heating Element

The heating element in a dishwasher is there to heat the water up in order to get the dishes clean. If it becomes defective, the water will fail to heat up, the dishes won’t clean properly and they won’t dry either.

If you are a competent DIYer, you can check the heating element using a multimeter. You will need to unplug the appliance and then unplug the connectors from the heating element. Place the multimeter’s probes on the heating elements terminals and check for continuity.

If there is no continuity, the heating element is at fault and will need to be replaced.

Defective Thermostat (Temperature Sensor)

The temperature sensor detects the temperature of the water and sends messages to the control board allowing it to adjust the temperature as necessary. If the sensor is defective, it can prevent the water from heating at all or only allow the water to heat up slightly.

You can check the thermostat for continuity and if it has no continuity it will need to be replaced. Accessing the thermostat can be difficult as it often involves dismantling the appliance. Which is why we recommend getting a technician to check this for you.

Defective Pressure Switch

If the pressure switch is defective on your dishwasher, it could cause the water to not heat up and you might encounter additional problems with the water level too. The dishwasher could not fill enough or overfill with water.

We recommend getting a technician to check this part for you.

Blocked Compression Chamber

The pressure switch controls the water level by means of the compression chamber. When there is sufficient water in the appliance the heating element kicks in to get it to the correct temperature.

If the compression chamber becomes blocked, it will send the wrong signal to the pressure switch which will mean the water doesn’t reach the required temperature.

The compression chamber can get blocked by grease, fat or other debris. This is another job best left to a technician.

Damaged Electrical Wires

Pretty much every functioning part of the dishwasher is connected by electrical wires. Over time, it’s possible for one or some of these wires to become degraded or detached from their component parts.

If this happens it’s entirely possible that it would prevent the appliance from heating up.

As there are so many wires connecting to many different components, we recommend getting a technician to check the wiring out.

Defective PCB

The Printed Circuit Board (PCB) is basically the controller on a dishwasher. It controls all of the functions and parts of the appliance. If it develops a fault, it could cause the appliance to not heat up.

However, it can be difficult to determine that the PCB is at fault because various other components can cause it to fail. Unless you can see visible signs of damage to the PCB you can’t be sure it is causing the fault.

To access the PCB involves removing panels and as the PCB is quite delicate, we recommend getting a technician to check this for you.

SEE ALSO: How To Clean & Sanitise A Dishwasher (to remove smells & dirt)

Frequently Asked Questions