If your AEG dishwasher is leaving food residue, cloudy glasses, or poorly washed dishes, you are not alone. Many owners in Spain face this issue, and the cause is often simple to diagnose. This guide covers the most frequent reasons for poor cleaning performance, from blocked filters to incorrect detergent use. We'll walk you through each potential problem, offer practical solutions, and direct you to further resources. For a broader overview of AEG appliance issues in Spain, see The Complete Guide to AEG Appliance Repair in Spain.

1. Clogged or Dirty Filters

The filter assembly at the bottom of your AEG dishwasher traps food particles. If it becomes blocked, water circulation is restricted, leading to poor cleaning. AEG recommends cleaning the filters every month or after every 10–15 cycles, depending on usage.

How to check and clean the filters

  • Remove the lower rack to access the filter.
  • Turn the coarse filter (the large cylindrical piece) counterclockwise and lift it out.
  • Remove the fine filter (flat mesh) beneath it.
  • Rinse both under hot running water, using a soft brush if needed. Do not use abrasive cleaners.
  • Reassemble and twist the coarse filter clockwise until it clicks.

If the filter is damaged or cracked, replace it. A new AEG filter costs around €15–€25 from retailers like MediaMarkt or El Corte Inglés.

2. Blocked Spray Arms

The spray arms rotate to distribute water. If their nozzles are clogged with food debris or limescale, water jets become weak, leaving dishes unwashed. This is common in areas with hard water, such as parts of Madrid or Barcelona.

Inspecting and cleaning spray arms

  • Remove the upper and lower spray arms by unscrewing the retaining nut or unclipping them.
  • Use a toothpick or a small wire to clear the holes.
  • Rinse under running water.
  • Check that the arms spin freely when reinstalled.

For heavy limescale, soak the arms in a solution of white vinegar and water (1:1) for 30 minutes. AEG also sells a dishwasher cleaner (€8–€12) that helps remove scale buildup.

3. Water Temperature Issues

AEG dishwashers typically heat water to 50–70°C depending on the program. If the water is not hot enough, grease and dried-on food won't dissolve. Possible causes include a faulty heating element, a defective thermostat, or an incoming water supply that is too cold.

To check, run a short cycle and feel the water at the bottom of the dishwasher after 10 minutes. It should be hot. If it's lukewarm, the heating element may need replacement. In Spain, a new heating element costs around €40–€60, plus labor if you hire a technician. Before calling, ensure the water supply temperature is at least 15°C; if your home's cold water is very cold in winter, consider using the “Pre-Wash” or “Intensive” program.

4. Incorrect Detergent or Rinse Aid

Using the wrong detergent or too little can cause poor cleaning. AEG recommends using high-quality dishwasher detergent (powder, gel, or tablets) and rinse aid for spotless drying. In Spain, brands like Finish, Somat, and AEG's own detergent are widely available.

Common detergent mistakes

  • Using hand dishwashing liquid – creates excess foam and reduces cleaning power.
  • Underfilling the detergent dispenser – always fill to the marked line.
  • Using old or clumped detergent – check expiration dates.
  • Not using rinse aid – essential for drying and preventing water spots.

Rinse aid should be refilled when the indicator light turns on. A bottle of Finish rinse aid costs about €3–€5 at Mercadona or Carrefour.

5. Overloading or Improper Loading

Packing too many dishes blocks water and detergent from reaching all surfaces. AEG recommends leaving space between items and placing heavily soiled dishes facing the spray arms. For example, plates should be angled downward, and large pots should be placed on the lower rack, not blocking the spray arm rotation.

If you consistently overload, consider upgrading to a larger AEG model (e.g., the 60 cm wide models). Overloading is one of the most common user errors leading to poor cleaning.

6. Hard Water and Limescale Buildup

Spain has varying water hardness levels. In regions with very hard water (over 200 ppm), limescale can accumulate inside the dishwasher, clogging spray arms and coating the heating element. This reduces cleaning efficiency and can cause white residue on dishes.

AEG dishwashers have a water softener that uses salt. Check the salt reservoir and refill with dishwasher salt (e.g., Finish or AEG brand, around €3 per 2 kg bag). Adjust the water hardness setting according to your local water supplier's data. For Barcelona, hardness is typically 18–25 °dH; for Madrid, 10–15 °dH. You can adjust the setting in the control panel (see your manual).

If limescale is already present, run an empty cycle with a descaler (e.g., AEG Dishwasher Cleaner, €10–€15) or a cup of white vinegar placed in a bowl on the top rack.

7. Error Codes and Electronic Faults

Modern AEG dishwashers display error codes when a problem is detected. Common codes include i10 (water intake fault), i20 (drainage problem), and i30 (anti-flood system activated). These can affect cleaning if the machine stops mid-cycle. For a full list, see AEG Dishwasher Error Codes.

If you see an error code, consult the manual or the linked article. For drainage issues, check the hose and filter; for intake problems, ensure the water tap is fully open and the inlet hose is not kinked.

When to Call a Technician

If you've tried all the above steps and your AEG dishwasher still doesn't clean properly, the issue may be a faulty circulation pump, a broken control board, or a worn-out motor. In such cases, contact an authorized AEG service technician. In Spain, you can find certified repairers through the AEG website or local appliance repair shops. Typical service call fees range from €50–€90, plus parts and labor. For more on general AEG repairs, refer to The Complete Guide to AEG Appliance Repair in Spain.

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