H21
Panasonic
Drainage System Blockage Detected
Dishwasher shows H21 and stops with water in the tub
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Blocked drain hose or sink connection, Clogged sump filter, Foreign object in drain pump, Incorrect drain hose installation height
How to Fix / Troubleshooting
Safety first: Disconnect power before working under the sink or on the pump.
- Clean internal filters: Remove and clean the Panasonic fine and coarse filters. Check the sump for food sludge or foreign objects.
- Inspect sink connection: Remove the drain hose from the sink trap or garbage disposer. Clear any blockage and ensure the knockout plug in a new disposer has been removed.
- Verify hose routing: Ensure the drain hose has a high loop under the counter but is not higher than the manufacturer’s specified maximum height. Remove any kinks.
- Check pump for debris: Access the drain pump from the base, remove the pump cover, and clear any obstructions from the impeller.
Run a cancel/drain cycle to confirm proper drainage. If H21 returns, the drain pump may be weak and require replacement.
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Repair Difficulty
Medium
3/5
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