LG Dryer Error Code E21 — Drain Pump Issue (Combo/Ventless Models)
What this means
The E21 error code appears on LG combo washer-dryer units and ventless condensing dryers. It indicates the drain pump is not removing condensation water from the sump quickly enough. This can be caused by a kinked drain hose, a clogged drain pump filter, a frozen sump (in cold environments), or a failing drain pump motor. On LG WashCombo all-in-one units, this error typically appears during the drying cycle when the unit needs to drain condensed moisture but cannot. The dryer will pause or stop the cycle until drainage is restored.
Step-by-step fix
4 stepsCheck the drain hose
Inspect the drain hose at the back of the unit. Make sure it is not kinked, crushed, or pinched against the wall. Straighten any bends and ensure the hose routes downward to the drain point without rising above the connection point.
The drain hose should be no higher than 39 inches from the floor when connected to a standpipe. Excess height creates back pressure.
Clean the drain pump filter
Locate the drain pump filter access panel (usually at the front bottom of the unit). Place towels and a shallow pan underneath. Open the panel, slowly unscrew the filter cap, and let trapped water drain. Remove the filter and clean any lint, debris, or small objects caught in it.
Coins, hair pins, and small fabric items are common culprits. Check the pump impeller behind the filter for obstructions as well.
Check the drain hose end for clogs
Disconnect the drain hose from the standpipe or drain point. Blow through it or flush it with water to check for internal clogs. Remove any lint or debris buildup.
If using a condensation collection tank instead of a direct drain, empty the tank — a full tank prevents further drainage.
Test the drain pump
If the hose and filter are clear, the drain pump motor itself may have failed. Run a drain-only cycle and listen for the pump activating. If you hear nothing or a continuous humming without drainage, the pump may need replacement.
A humming pump that does not drain may have a seized impeller. A silent pump has a failed motor.
When to call a professional
If the drain pump motor has failed, a technician should replace it. On combo washer-dryer units, the pump is shared between wash and dry functions, so a failure affects both cycles.
Related error codes
Information compiled from manufacturer service manuals, official troubleshooting documentation, and appliance repair industry resources. This guide is for informational purposes only — always consult a qualified technician for complex repairs.
Learn more about our sourcesParts you may need
Drain Pump Motor Assembly
Part #4681EA2001T · $25–$50
If the drain pump motor is not running or the impeller is seized
Drain Hose
Part #AEM73732901 · $15–$25
If the hose is damaged, kinked, or clogged beyond cleaning
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