E9 error, unit may leak water or shut down unexpectedly

Safety: Turn off power to the indoor unit before working around water and electrical components.

• Inspect drain pan: Remove the access panel and check the primary drain pan under the Fraser‑Johnston evaporator coil. If full of water, the drain is likely clogged.
• Clear drain line: Use a wet/dry vacuum at the outside drain termination to pull out sludge and debris. Alternatively, use a condensate line cleaning brush or compressed air (carefully).
• Check float switch: Locate the condensate float switch (often wired in series with the thermostat Y circuit). Ensure it moves freely and is not stuck in the up (full) position. Replace if defective.
• Verify slope and trap: Ensure the drain line slopes downward away from the unit and that the trap is properly installed and not blocked.
• Test operation: After clearing, pour water into the pan to confirm proper drainage and that E9 clears when the pan is empty.