Indoor unit shows E9 and may stop; often associated with water leakage or abnormal defrost behavior.

Safety first: Turn off and unplug the unit before working on the drain system. Water and electricity are a dangerous combination.

Steps:

• Check drain hose: For wall splits, ensure the drain hose slopes continuously downward with no kinks. For portable units, verify the drain hose is not blocked and the tank is emptied.
• Clean drain line: Use a wet/dry vacuum on the outside drain termination to suck out sludge and algae. Alternatively, blow compressed air from the indoor side to clear blockages.
• Inspect drain pan: Remove the indoor front cover and filters. Check the plastic drain pan under the evaporator for dirt buildup or misalignment. Clean with mild detergent and water.
• Float switch / sensor: On models with a float switch, locate it in the drain pan and ensure it moves freely. Test continuity while moving the float; replace the Blaupunkt drain float switch if stuck or electrically open/shorted.