Heater displays E15; may occur in cold or damp weather

Safety first: Turn OFF power before working around the condensate system. Condensate is mildly acidic; wear gloves and eye protection.

• Inspect drain tubing: Follow the condensate drain from the heater to its termination. Look for kinks, sags, or blockages. Clear any debris and ensure continuous downward slope.
• Clean trap: Remove and flush the condensate trap with clean water to remove sludge or scale. Refill the trap with water before reinstalling to maintain the seal.
• Check float switch: If equipped, inspect the condensate float switch in the drain pan. Ensure it moves freely and wiring is intact.
• Protect from freezing: In cold climates, insulate or heat-trace exposed condensate lines to prevent freezing.

Warning: Do not operate the heater with a blocked condensate drain; water can back up into the heat exchanger and electronics.