E11 displayed, unit may shut down unexpectedly; pressure reading may be abnormally high.

Warning: High pressure can cause the relief valve to discharge hot water. Use caution and allow the system to cool.

• 1. Check pressure gauge: If the gauge reads above normal (often >30 psi), stop the heater.
• 2. Inspect expansion tank: Tap the tank; it should sound hollow on the air side. If it sounds solid, the bladder may have failed.
• 3. Verify air charge: Isolate and drain the tank, then check air pressure with a tire gauge. Recharge to specs (often 12 psi).
• 4. Reduce system pressure: Carefully drain water until the gauge returns to the recommended range.
• 5. Check fill valve: Ensure the automatic fill valve is not leaking water into the system constantly.
• 6. Professional service: If the tank is waterlogged, have a technician replace it.