Display shows E10, furnace locks out, often related to condensate or water level issues on condensing Termet units.

Safety: Turn off power. Condensate may be mildly acidic; wear gloves and eye protection.

• Inspect condensate trap: Locate the plastic condensate trap at the bottom of the heat exchanger. Remove it according to the Termet manual. Flush with clean water until all debris is removed.
• Check hoses: Ensure the condensate hose from the trap to the drain is not kinked, sagging, or blocked. Clear any slime or buildup.
• Check external drain: Make sure the drain line is not frozen or blocked where it exits the building.
• Check level sensor (if present): Some Termet models have a float or electrode sensor in the trap. Clean the sensor and ensure it moves freely.

After cleaning, reinstall the trap, restore power, and reset the furnace. If E10 returns, have a technician inspect the condensate system and sensor wiring.