Harsco Industrial SC-2000 Installation & Owner's Manual page 43

When 65: "Interrupted Airflow Switch OFF" is displayed, check that the air switch is closed when the
blower is running. If the air switch does not close within 5 minutes during purge, the boiler locks out. Check
that the burner is clean ("Cleaning the Burner,"
intake or exhaust ducts.
5.5.7 Flame Failure
In the event of a flame failure, the NURO control may display one of the following error messages:

106: "Flame Lost in Main Flame Establish Period"

107: "Flame Lost Early in Run"

108: "Flame Lost in Run"

109: "Ignition Failed"

110: "Ignition Failure Occurred"
When 109: "Ignition Failed" or 110: "Ignition Failure Occurred" is displayed, the boiler did not light during
the trial for ignition. Check that the ignition electrode, ignition wire, and gas valve are functioning properly.
Check that the direct spark ignition is visible through the flame observation port during the trial for ignition.
When 106: "Flame Lost in Main Flame Establish Period", 107: "Flame Lost Early in Run", or 108: "Flame
Lost in Run" is displayed, the boiler lost the flame signal during operation. Check that combustion is adjusted
properly, the gas pressure is correct, and the ignition electrode, ignition wire, and gas valve are functioning
properly.
5.5.8 Flame Error
In the event of a flame error (premature or late flame signal), the NURO control will display 105: "Flame
Detected Out of Sequence". This may be caused by a failed/leaky gas valve or a flame rod or ionization
rod malfunction. If gas valve leakage is suspected, the unit must be isolated by turning off the main gas
supply line. Lockout/tagout the boiler until qualified and knowledgeable service personnel are available to
evaluate and repair or replace the failed parts. Check that the incoming gas pressures have not exceeded
14" w.c. (1/2 psig).
5.5.9 Flue Problem
When the normally-closed high exhaust back pressure switch opens, the NURO control will display 10013:
"High Back Pressure Limit". This may be caused by an obstruction in the flue piping, an obstruction in the
combustion air intake, or a blocked condensate system. When the blockage is removed, the boiler will
automatically restart. If no blockage is found, it may be necessary to replace the high exhaust back pressure
switch.
Harsco Industrial, Patterson-Kelley Technical Service 1.877.728.5351
Section 5.2) and that there are no obstructions to airflow in the
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Gas Fired Boiler