Indoor unit shows E9 and may leak water or stop cooling

Safety first: Turn off power to the indoor unit. Water and electricity are a dangerous combination.

Steps to try:

• Check drain hose: Locate the condensate drain hose exiting the indoor unit. Ensure it slopes continuously downward with no kinks or loops that trap water.
• Clear the drain line: At the drain outlet, use a wet/dry vacuum to suck out debris and algae. Seal the hose to the vacuum with a rag for better suction.
• Inspect drain pan and float switch: Remove the indoor front cover and lower panel (if accessible). Look for standing water in the pan. Gently lift and release the float switch to ensure it moves freely.
• Level the unit: Use a small level to confirm the indoor unit is slightly tilted toward the drain side. Adjust mounting bracket if necessary.

When to call a pro: If E9 persists and the drain is clear, the float switch or indoor PCB input circuit may be faulty and require replacement.