Unit shows E09 and shuts down; may be accompanied by gurgling sounds in the vent or condensate lines.

Safety: Turn OFF power. Avoid spilling condensate on electrical components.

• Locate condensate trap: Find the Alpha condensate trap at the bottom of the heat exchanger or flue collector.
• Inspect and clean: Remove the trap following Alpha instructions. Flush it with clean water to remove sludge or debris. Ensure the internal float (if present) moves freely.
• Check drain hose: Verify the condensate hose slopes continuously downward to the drain and is not kinked or frozen. Clear any blockage with a flexible brush or by flushing with water.
• Reassemble and test: Reinstall the trap, restore power, and run the unit. Watch for leaks and confirm E09 clears.

If condensate repeatedly backs up, have the drain system and venting evaluated by a professional.