Control indicates 'Condensate Blocked' or 'Drain Fault'; unit may shut down and display a fault.

Safety first: Turn off power. Condensate is mildly acidic; wear gloves and eye protection when handling.

• Locate condensate trap: Find the clear or opaque plastic trap assembly at the base of the heat exchanger or flue outlet.
• Inspect for blockage: Remove the trap per the manual. Look for sludge, debris, or scale. Rinse thoroughly with clean water until flow is clear.
• Check drain tubing: Ensure the tubing from the trap to the drain is not kinked, sagging excessively, or frozen. Correct routing and provide insulation or heat tape if freezing is an issue.
• Refill trap: Before reassembling, fill the trap with clean water to restore the water seal, which prevents flue gases from escaping.
• Test operation: Restore power and run the unit. Verify that condensate flows freely to the drain during operation.