Boiler controller shows E02 and burner locks out shortly after flame is established.

Safety: Switch off power to the Danstoker boiler and close the fuel supply before opening burner components. Allow the boiler to cool.

• Check fuel pressure and supply: Verify that gas pressure at the burner gas train (upstream and downstream of the Danstoker-specified gas valve train) is within design range. For oil, check the oil pump pressure gauge and ensure filters are not clogged.
• Inspect flame sensor: Remove and clean the ionization rod or UV sensor. Ensure correct insertion depth and alignment with the flame. Check the sensor cable for damage and secure all terminals at the burner control.
• Clean burner head/nozzle: Remove the burner lance or head and inspect the gas ports or oil nozzle for carbon, soot, or debris. Clean or replace the nozzle as per burner manufacturer’s instructions.
• Check combustion air: Ensure the combustion air fan on the Danstoker burner is running freely, air intake is not blocked, and any air dampers or VFD settings are correct. Restricted air can cause unstable flame.

If the flame still drops out and E02 recurs, a qualified technician should measure flame signal strength, verify burner control timings, and adjust combustion settings.