E12
A.O. Smith
Flame Rod Short / Ground Fault
A.O. Smith water heater shows E12; unit may lock out after several failed starts
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Flame sensor rod shorted to burner, Damaged flame sensor insulator, Moisture or condensation on flame rod, Wiring harness short to ground
How to Fix / Troubleshooting
Safety: Turn off gas and power before opening the burner compartment.
- 1. Inspect flame rod: Remove the burner assembly and examine the flame sensor rod. Ensure the ceramic insulator is intact and the rod is not touching metal except at its mounting point.
- 2. Clean and dry: Wipe the rod and insulator with a clean, dry cloth. If there is condensation, allow the area to dry completely before reassembly.
- 3. Check wiring: Follow the flame sensor wire back to the control. Look for chafed insulation or spots where the wire may contact sharp metal edges. Repair or replace damaged wiring.
- 4. Reposition sensor: Make sure the rod is properly positioned in the burner flame path but not contacting the burner surface.
- 5. Replace sensor: If the insulator is cracked or the rod is heavily corroded, replace the flame sensor assembly.
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Repair Difficulty
Medium
3/5
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