Dishwasher tablet not dissolving: causes and safe checks

Usually simple

Quick answer

A tablet left in the dispenser usually means something blocked the detergent lid from opening, such as a pan handle or a tall plate, or the spray arms couldn’t reach it because they’re blocked. Load so nothing sits in front of the dispenser, clear the spray arms and filters, and check the water is getting hot.

Also covers: dishwasher tablet left in dispenser · dishwasher detergent not dissolving.

Likely causes

What you can safely check yourself

Stop and call a qualified engineer if:
  • It still doesn’t heat after the checks. Heating faults need an engineer.
  • The code or problem comes back after you’ve done the safe checks on this page.
  • The next step would mean removing a cover or panel, or working on the pump, valves, heater, motor, door lock or wiring. That is a job for a qualified engineer.

Work through these in order. Stop as soon as one of the signs above applies.

Check the loading

  1. Make sure nothing stops the spray arms turning or blocks the detergent compartment lid.
  2. Leave space between items so water and heat reach every surface.
  3. Put heavily soiled pans in the lower basket, and cups and glasses in the upper basket.
  4. Scrape food off plates before loading.

Check the spray arms turn and aren’t blocked

Before you start
  • Switch off and unplug the appliance at the wall socket before you touch hoses, filters or the back of the machine. Make sure your hands and the plug area are dry.
  1. With the dishwasher switched off, turn each spray arm by hand. It should spin freely without hitting plates, pans or utensils.
  2. Look at the nozzle holes. Clear food or limescale with a cocktail stick or tweezers.
  3. If your manual shows how to remove the spray arms, rinse them through under the tap and refit them firmly.

Clean the dishwasher filters

Before you start
  • Switch off and unplug the appliance at the wall socket before you touch hoses, filters or the back of the machine. Make sure your hands and the plug area are dry.
  • Wear protective gloves. Broken glass and sharp debris can collect in the filter and pump area, and it is hard to see.
Dishwasher filter assembly Twist to unlock, lift out Coarse filter Flat fine filter sits flat in the base Wear gloves: glass collects here. Refit until it locks.
Dishwasher filter assembly. Positions vary by model — check your manual.
  1. Take out the lower basket.
  2. Twist and lift the filter unit out of the base of the tub, then separate the parts as your manual shows.
  3. Rinse every part under running water. Use a soft brush for stubborn debris and nothing abrasive.
  4. Wipe food remains out of the sump area around the filter opening.
  5. Refit the filters so they lie flat and lock in position. On many models arrows line up when they are locked.

Don’t run the dishwasher without the filters fitted.

Showing an error code?

These codes are related to this problem. Codes differ by brand, so pick yours:

Step-by-step guides

Related problems

Brand guides: Bosch, Samsung. More dishwasher problems and codes, or use the fault finder.

Sources

Last checked against these sources: .

We write every page in our own words from manufacturer guidance and check it against the sources above. If your manual says something different, follow your manual. How we check.