To clean a Thermador dishwasher filter, switch the dishwasher off, pull out the lower rack, turn the drain filter at the bottom of the tub counterclockwise to release it, rinse it under running water with a soft brush, wipe out the housing and lock it back in place. Our maintenance guide recommends doing this monthly, and it is the single most useful routine task on the machine, because a clogged filter causes slow draining, odors, gritty dishes and the drain error codes that lead to service calls. This guide covers the steps, the signs that the filter is dirty and what to do when cleaning does not help.
Why does a Thermador dishwasher filter need cleaning?
The filter catches food particles before they reach the drain pump and the spray arms. When it clogs, water drains slowly or not at all, and dirty water recirculates over the dishes. Our Thermador dishwasher not draining guide calls clearing the drain filter the first step in any drain problem, and our maintenance guide says that a clean filter every month prevents most E24 and E25 drain codes and keeps wash performance up.
Signs that the filter needs attention include standing water after a cycle, a sour smell when you open the door, a gritty film on glasses and plates, and a cycle that takes longer than usual. If you see any of those, clean the filter before you look at anything else. It costs nothing, takes a few minutes and answers many of the questions people search for, such as why a dishwasher smells or does not drain.
How do you remove and clean the drain filter?
Start by switching the dishwasher off and letting the water cool. Pull out the lower rack all the way and set it aside. Look at the tub floor for the filter assembly. The exact shape differs between Thermador tiers and years, so have your owner’s manual open at the filter page. Per our not draining guide, the drain filter is turned counterclockwise to remove it.
Lift the filter out and tip any trapped debris into the trash, not the sink. Rinse it under warm running water and scrub gently with a soft brush or an old toothbrush to loosen grease and food. Do not use abrasive pads or sharp tools, which can damage the mesh. If the filter has more than one part, take them apart as the manual shows and clean each one. Do not use liquid dish soap in the dishwasher itself; our guides warn it creates excessive suds.
What should you wipe or check around the filter?
With the filter out, wipe the housing in the tub floor with a damp cloth, taking care not to push debris into the drain opening. Look for glass shards, bone pieces or small utensil parts. Our not draining guide says to check the pump cover beneath the filter and make sure nothing jams the impeller, and that the impeller should spin freely by hand. Be careful: broken glass can be hidden in the sump, so wear gloves and do not put your hand where you cannot see. Before you reach toward the pump area, switch the dishwasher off at the breaker from a dry spot, not only at the control panel.
If the pump area is not easy to reach on your model, stop. Do not take the pump or wiring apart yourself. Switch off the dishwasher at the breaker from a dry spot, and call a technician if the pump is stuck or if water leaks near any electrical part.
How do you put the filter back correctly?
Reinstall the pieces in the reverse order and turn the filter clockwise until it locks. Make sure it sits flat and fully seated, because a filter that is loose lets debris past it and can rattle during the cycle. Replace the lower rack and run a short rinse cycle with the door closed, then look at the tub floor for standing water. If you cleaned the filter and still see water, the problem is somewhere else in the drain path.
Never run the dishwasher without the filter in place. Debris will go straight to the pump, and it is the quickest way to turn a small clog into a repair. Our Thermador dishwasher maintenance schedule covers the other monthly, quarterly and yearly checks, including the gasket and the spray arm nozzles.
What if cleaning the filter does not solve the problem?
Work through the other usual causes in order. Check the drain hose for kinks and make sure the knockout plug was removed from a garbage disposal inlet. If water still stays in the tub, if a drain code returns, or if the pump hums or grinds, the problem is beyond the filter. Our Thermador dishwasher error codes guide lists what each code means. Never ignore a repeating code, since our maintenance guide notes that codes are diagnostic aids meant to prevent small issues from becoming major failures.
For loading habits that keep a filter cleaner, such as scraping plates and not overloading racks, see our dishwasher loading tips. Use dishwasher detergent only: our guides warn that liquid dish soap creates excessive suds and can damage the pump.
We are an independent repair company, not the manufacturer. Our Thermador dishwasher repair page explains how a visit works, and you can schedule a visit online.
