Electronic gas water heater shows E13; unit may not fire or may shut down during operation.

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

• 1. Inspect condensate trap: Locate the condensate trap at the base of the heater. Remove and check for debris, sludge, or scale. Clean thoroughly with water.
• 2. Check drain line: Follow the condensate line to its termination. Ensure it is not kinked, frozen, or blocked. Clear any obstructions and verify proper slope for drainage.
• 3. Verify neutralizer (if equipped): If a condensate neutralizer cartridge is installed, ensure it is not clogged. Replace media if saturated.
• 4. Examine heat exchanger: If E13 recurs and condensate flow is poor, the internal passages of the condensing heat exchanger may be restricted by scale or debris. Professional descaling may be required.
• 5. Test operation: After cleaning, reassemble the trap, prime it with water, and test the heater. Confirm a steady drip or flow of condensate during operation.