Portable Honeywell AC shows E4 and stops cooling; unit may beep and shut down.

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

Steps:

• Check and empty the tank: On most Honeywell portable ACs, there is a lower drain plug or a removable internal tank. Place a shallow pan or tray under the drain, remove the cap, and allow water to drain completely. Reinstall the cap securely.
• Inspect the float switch: If your model has an internal float, remove the rear panel to access the condensate reservoir. Verify that the float moves freely up and down and is not stuck by dirt or scale. Clean the float and reservoir with mild detergent and water.
• Clear the drain path: If using continuous drain, disconnect the hose and flush it with water to remove clogs. Ensure the hose slopes downward with no kinks.
• Check wiring: Inspect the float switch or water level sensor wiring for loose connections or corrosion at the control board.
• Test operation: Reassemble, plug in, and power on. If E4 clears and does not return, the issue was likely a full tank or stuck float.
• Replace components: If the float switch is physically damaged or does not change state when moved, replace the float switch or water level sensor assembly with a Honeywell-compatible part.