Furnace displays E16, sometimes accompanied by water around the base of the unit.

Safety: Turn off power before servicing the condensate system. Be prepared for water spillage.

Steps:

• Locate trap and drain: On condensing Atlantic furnaces, find the plastic condensate trap and attached drain tubing.
• Clear the trap: Remove the trap (note orientation), flush it with warm water, and clear any slime or debris. Reinstall in the correct orientation.
• Flush drain line: Disconnect the drain hose and blow through it or flush with warm water to remove blockages. Ensure the outlet is free and properly sloped.
• Check condensate pump: If a pump is used, verify it has power and that the float switch moves freely. Clean or replace the pump if it does not run when the reservoir fills.
• Inspect condensate safety switch: Some Atlantic models use a float or pressure switch that opens when water backs up. Ensure it resets after clearing the blockage.

After clearing: Restore power and run the furnace. Confirm that condensate flows freely to the drain.