Indoor unit shows E9; sometimes associated with water leakage or full drain pan

Safety first: Turn off power before working near water and electrical components.

Steps to check:

• 1. Inspect drain line: Locate the condensate drain pipe from the indoor unit. Check for kinks, upward loops, or visible blockages. Ensure it slopes downward continuously.
• 2. Clear blockage: Use a wet/dry vacuum at the drain outlet outside to suck out sludge and algae. Alternatively, blow compressed air from the indoor side if accessible.
• 3. Check float switch: On cassette/ducted units, open the access panel to the drain pan. Locate the float switch. Ensure it moves freely and is not stuck in the UP position due to dirt or slime. Clean the pan and switch.
• 4. Test condensate pump (if present): Pour a small amount of water into the drain pan and observe if the pump activates and discharges water. If not, the pump or its power supply may be faulty.

When to call a technician: If E9 persists after cleaning and drain correction, the float switch or pump assembly may need replacement and should be handled by a professional.