The dishwasher has stopped heating the water, but the dishes remain cold and greasy after washing? This is one of the most common malfunctions that equipment owners encounter. Bosch, Electrolux, Samsung and other brands. The reasons may lie in either banal clogged filters or serious breakdowns of the heating element or electronics. In 80% of cases, the problem can be fixed on your own - without calling a specialist and costly repairs.

In this article we will analyze all possible reasons, why the dishwasher (DMM) does not heat the water, and we will also give step-by-step diagnostic and repair instructions with your own hands. You will learn how to check the heating element, thermostat and control board, what tools you will need, and when you should contact a service center. We will pay special attention hidden faults that are often missed even by experienced craftsmen - for example, the problem may lie in the flow sensor or incorrect firmware of the control unit.

1. Signs that the dishwasher is not heating the water

Before disassembling the equipment, make sure that the problem is really related to heating. Here are the key symptoms:

  • 🧊 Dishes stay cold after the end of the program - even an hour after washing, the plates and glasses are not heated.
  • ⏳ The program takes longer than usual — the machine “freezes” during the heating or rinsing stage, as it waits for the set temperature to be reached.
  • 💧 The water in the tank is cold — if you touch the body during operation, it does not heat up (normally it should be warm).
  • 🚨 Errors on the display - codes E01, E09 (y Bosch), 4E (y Samsung) or i30 (y Electrolux) often indicate heating problems.

If at least one of the signs matches, it means that the machine really does not heat the water. But before repairing, exclude false positives:

  • 🔌 Check if the heating is turned off in Eco mode (for some models Siemens and AEG there is a cold wash option).
  • 🌡️ Make sure that the incoming water temperature is not lower than +10°C (at +5°C and below, many PMMs do not turn on the heating element).
📊 What brand of your dishwasher?
Bosch
Electrolux
Samsung
Indesit
Other

2. TOP 7 reasons why PMM does not heat water

Let's sort it out all possible reasons - from the simplest to the most complex. Start checking from the first point and move along the list until you find the fault.

Reason How it manifests itself Difficulty of repair
Clogged filters or injectors Water circulates poorly, heating turns on with a delay ⭐ (easy)
Malfunction of the heating element (heating element) The water does not heat up at all, errors on the display are possible ⭐⭐ (average)
Broken thermostat (temperature sensor) The machine either does not heat the water or overheats it ⭐⭐ (average)
Malfunction of the control unit (board) Incorrect operation of programs, random errors ⭐⭐⭐ (difficult)
Broken heating element power supply circuit There is no heating, but the heating element is working (the problem is in the wires or relay) ⭐⭐ (average)

Now we will analyze in detail each reason and how to eliminate it.

3. Clogged filters and nozzles: how to clean them yourself

If the dishwasher does not heat water well or heating takes too long, the first reason is clogged filters or nozzles. Due to scale, food residues or detergent, water circulation is disrupted and the heating element cannot work normally.

What to do:

  1. Unplug the machine and turn off the water.
  2. Lift out the lower basket and remove the filter (usually it is located at the bottom, under the spray arm).
  3. Rinse the filter under running water, removing plaque and debris. For heavy stains, use a toothbrush and vinegar.
  4. Check the spray nozzles - clean them with a needle or toothpick.
  5. Put everything back together and run a test wash.

Remove the baskets from the chamber|Remove and wash the coarse filter|Clean the fine mesh filter|Clean the upper and lower spray nozzles|Check the drain hose for blockages-->

If the problem remains after cleaning, proceed to checking the heating element.

💡

To prevent blockages, run the machine once a month with citric acid (2 tablespoons per empty cycle at 60°C). This will remove scale and extend the life of the heating element.

4. Diagnostics and replacement of the heating element of the dishwasher

A heating element (tubular electric heater) is main element, responsible for heating water. If it is burnt or covered with a thick layer of scale, the machine will not be able to heat water. How to check the heating element:

  1. Disconnect the PMM from the mains and drain the water (tilt the machine forward, placing the container).
  2. Remove the bottom panel (on most models it is secured with latches or screws).
  3. Find the heating element - it looks like a curved tube with terminals (usually located at the bottom, under the tank).
  4. Disconnect the wires and check the resistance with a multimeter:
    • 🔌 Normal resistance: 20-40 ohms (depending on model).
    • 🚫 Break (infinity) or short circuit (0 ohm) — The heating element is faulty.

If the heating element is burnt out, it needs to be replaced. To do this:

  1. Buy a new heating element (indicate the machine model, for example, Bosch SMV46MX01R or Electrolux ESL94585RO).
  2. Unscrew the fastening nuts of the old heating element and carefully remove it.
  3. Install the new one, connect the wires and assemble the car.
How to check a heating element without a multimeter?

If you don’t have a tester at hand, you can visually inspect the heating element for blackening, swelling or cracking. Also pay attention to the contacts - if they are melted or covered with a green coating (oxidation), this is a sign of a malfunction. However, this method does not provide a 100% guarantee, so it is better to use a multimeter.

⚠️ Attention! When replacing the heating element, do not use excessive force - its body is fragile. If you squeeze it, the tank may crack, which will require expensive repairs.

5. Checking the thermostat and temperature sensor

The thermostat (or NTC sensor) controls the water temperature. If it fails, the machine either doesn't heat water, or, conversely, overheats her. How to check:

  1. Find the thermostat - it is located next to the heating element or on the control board (depending on the model).
  2. Disconnect the connector and check the resistance:
    • 🌡️ At room temperature (~20°C) the resistance should be 10–20 kOhm.
    • 🔥 If you heat the sensor (for example, hold it in hot water), the resistance should decrease.
    • 🚫 If the readings do not change or are equal to 0/infinity, the sensor is faulty.

Replacing the thermostat:

  1. Buy a similar sensor (specify the model, for example, NTC 10kOhm for Bosch/Siemens).
  2. Unsolder or disconnect the old sensor (in some models it is secured with latches).
  3. Install a new one and connect the connector.
    4. 💡

    If the thermostat is working, but the machine still does not heat the water, the problem may be control unit — it does not give a signal to turn on the heating element.

    6. Problems with the control unit: diagnostics and repair

    If the heating element and thermostat are working, but there is no heating, the culprit is control unit (board). Common reasons:

    • 🔌 The heating element relay burned out — it is responsible for supplying power to the heater.
    • 🖥️ Microcircuit malfunction - for example, a firmware failure or a triac failure.
    • 💧 Short circuit due to moisture getting on the board.

How to diagnose:

  1. Remove the top cover of the machine (usually secured with 2-4 screws).
  2. Locate the control board (usually at the top, under the control panel).
  3. Examine it for an item blackened elements, swollen capacitors or signs of oxidation.
  4. Use a multimeter to test the power supply circuit of the heating element (from the board to the heater).

Board repair:

  • 🔧 If the relay burns out, replace it with a similar one (for example, Omron G2R-1).
  • 💻 If the problem is in the firmware, reflash the board (you will need a programmer and firmware files for your model).
  • 🚫 If the board is severely damaged (for example, the tracks are burned out), it is better to replace it entirely.
⚠️ Attention! Repairing the control board requires experience with electronics. If you are not confident in your abilities, it is better to contact the service - incorrect soldering can lead to complete failure of equipment.

7. Other possible causes and their elimination

If after checking the heating element, thermostat and board the problem remains, pay attention to:

  • 🔌 Broken wiring — check the circuit from the board to the heating element for damaged wires or oxidized contacts.
  • 💡 Flow sensor malfunction - if it falsely signals that there is no water, the machine will not turn on the heating.
  • 🚰 Low water pressure - with low pressure, some models (Indesit, Candy) refuse to heat the water.
  • ⚡ Problems with the outlet or surge protector — check the voltage in the outlet (should be ~220V).

To diagnose the flow sensor:

  1. Locate it (usually located at the water inlet, near the fill valve).
  2. Check the resistance - normally it should change as water flows.
  3. If the sensor does not respond, replace it.

If the cause is low water pressure:

  • Check if the inlet hose is kinked.
  • Clean the filter mesh at the entrance to the machine (it may become clogged with rust or sand).
  • Make sure that the pressure in the water supply is sufficient (at least 1-2 bar).

FAQ: Frequently asked questions about heating water in a dishwasher

❓ Why does the dishwasher take so long to heat the water?

This may be due to:

  • Clogged filters or nozzles (water circulates slowly).
  • A thick layer of scale on the heating element (heat transfer deteriorates).
  • The thermostat is faulty (it does not detect the temperature correctly).
  • Low voltage in the network (the heating element does not operate at full power).

Start by cleaning the filters and checking the heating element.

❓ Is it possible to use a dishwasher without heating the water?

Technically yes, but this ineffective:

  • Fat and food residues will be washed off less easily.
  • The detergent will not dissolve completely and will remain on the dishes.
  • The risk of bacteria growing in the car will increase.

If the heating is broken, it is better to repair the machine or wash the dishes by hand.

❓ How much does it cost to replace a heating element in the service?

The cost depends on the model and region:

  • Bosch/Siemens: 3,000–5,000 rub. (with spare parts).
  • Electrolux/Zanussi: 2,500–4,000 rub.
  • Indesit/Ariston: 2,000–3,500 rub.

Replacing it yourself will cost 2–3 times less (the price of a heating element is from 800 to 2,000 rubles).

❓ How often do you need to clean the heating element from scale?

Recommended Frequency:

  • For hard water - once every 2–3 months.
  • With soft water - once every 6 months.
  • If you use softeners (for example, Finish Calgonit) — once a year.

For cleaning, use citric acid or special products (Somat Machine Cleaner).

❓ Why does the machine heat the water, but the dishes remain dirty?

Possible reasons:

  • The spray nozzles are clogged (water does not reach the dishes).
  • There is not enough detergent or it is of poor quality.
  • The circulation pump is broken (water does not spray under pressure).
  • The dishes are loaded incorrectly (blocking the water supply).

Check the spray nozzles and pump, and monitor the dosage of detergent.