Bradford White power vent or condensing water heater displays E12 and shuts down.

Safety: Turn off power to the heater. Water may be hot; wear gloves and eye protection.

Steps:

• Locate condensate trap: On condensing models, find the plastic condensate trap at the base of the heat exchanger or blower.
• Clean trap: Remove the trap per manual instructions. Flush it with clean water to remove debris or sludge. Ensure internal floats (if present) move freely.
• Inspect drain line: Check the entire condensate line for kinks, sags, or freezing. Ensure it slopes continuously downward to a drain. Clear any blockage with water or a flexible brush.
• Reassemble and test: Reinstall the trap, restore power, and run the heater. Verify condensate flows steadily to the drain during operation.

If the code returns despite a clear drain, the internal condensate passages or sensor may be blocked or defective and require professional service.