E2
Ruud
Flame Loss / Flame Signal Fault
Boiler displays E2 and shuts down shortly after starting; burner may light briefly then go out
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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
Contaminated or mispositioned flame sensor, poor burner ground, low gas pressure, faulty ignition control circuit on main board
How to Fix / Troubleshooting
Safety first: Turn off power and gas before working inside the combustion compartment.
- Clean the flame sensor: Remove the flame sensor rod (usually held by one screw). Gently clean the rod with fine steel wool or emery cloth until shiny. Wipe with a dry cloth and reinstall, ensuring it is fully in the flame path.
- Check ground connections: Verify that the burner assembly and control board ground wires are tight and free of corrosion. A poor ground can cause weak flame signal.
- Inspect burner flame: With the front panel in place and viewing through the sight glass, check that the flame is stable and blue, not lifting or blowing off. Yellow, unstable flame may indicate gas or air issues that require a technician.
- Reset and test: Restore power and gas, then call for heat. If E2 returns after cleaning and checking grounds, the ignition control portion of the main board or gas valve may be faulty.
- Do not adjust gas valve: Gas pressure and combustion must be set with a manometer and combustion analyzer by a licensed technician.
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Repair Difficulty
Hard
4/5
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