Thermador Range Error Code E:21

E:21 on a Thermador WFMC washer indicates that excessive foam has been detected inside the drum during the wash cycle. Despite appearing on a Thermador-branded appliance, this code specifically applies to the WFMC washer model. The cause is almost always the use of the wrong detergent type or too much detergent. Switching to a properly dosed HE detergent is the primary fix.

Resetting the washer may clear the displayed error temporarily, but the code will return if the underlying cause is not addressed. Because E:21 is triggered by detergent-related foaming rather than a component failure, the fix must involve changing your detergent type or quantity. A reset alone without correcting detergent use will result in the error appearing again in the next cycle.

In most cases, resolving E:21 costs nothing beyond purchasing the correct HE detergent, which typically ranges from a few dollars to around $20 depending on the brand and quantity. No parts or service calls are generally required since the error is caused by detergent misuse rather than a component failure. If a technician visit is needed to inspect the pressure sensor or control board after ruling out detergent issues, service call fees typically range from $75 to $150 or more depending on your location.

Stop the current cycle and allow the foam to dissipate before restarting. Going forward, use only HE-rated detergent and follow the dosing instructions carefully, using less than the maximum recommended amount for lightly soiled loads. If the error keeps returning, run a drum-cleaning cycle to remove detergent residue buildup from the drum and gasket.

The E:21 error is not a safety hazard in the traditional sense. However, excessive foam can prevent the washer from rinsing clothes properly, leaving detergent residue on fabrics, which can irritate skin. Persistent foam buildup can also cause moisture and mold issues inside the machine over time if the drum and gasket are not kept clean.