Diagnosis
The internal condensate drain pan is overflowing. The drain line is either clogged, disconnected, or not pitched correctly for gravity drainage.
How to Fix It
Clear the primary 3/4" PVC drain line.
- Turn off the unit.
- Disconnect the drain line from the unit's drain port.
- Use a wet/dry vac on the line or flush it with water to clear any algae or debris.
- Reconnect, ensuring a continuous downward slope from unit to drain.
If That Didn't Work
Check the internal condensate pump (if equipped). Listen for a hum. If silent, the pump may have failed or its float switch is stuck. You'll need to access and inspect the pump assembly.
Heads Up
Algae growth in the line is common. Consider using condensate tablets in the drain pan to prevent future clogs. Always check the drain line routing first—it's the culprit 80% of the time.