Display shows E4 and unit stops cooling; may occur after long operation or in very humid conditions.

Safety: Turn the unit off and unplug it before draining water to avoid electrical shock.

• Drain the tank: Move the unit to a location where water spillage is acceptable. Remove the lower drain cap/plug at the back or side and allow all water to drain into a shallow pan or tray.
• Check continuous drain: If using a continuous drain hose, disconnect it and verify it is not kinked, clogged with debris, or routed uphill. Clean or replace the hose as needed.
• Inspect drain port: Use a small brush or pipe cleaner to clear any sludge or scale from the drain outlet on the unit.
• Float switch check: With the unit unplugged and drained, remove the lower rear panel to access the internal condensate tray. Locate the float or water level switch assembly. Ensure the float moves freely up and down and is not stuck by dirt or algae.
• Clean the tray: Wipe out any slime, mold, or mineral buildup from the condensate tray that could interfere with the float.
• Test switch (advanced): Disconnect the float switch connector and test continuity with a multimeter while moving the float. Replace the condensate float switch / water level sensor if it does not change state.
• Reset and test: Reassemble, plug in, and restart the unit. If E4 returns immediately with an empty tray and working float, the main control PCB may be misreading the sensor and require service.