LG AR-DR12-05A Installation And Operation Manual page 88

INDIRECT GAS FIRED FURNACES
Troubleshooting - Ignition Controller
Ignition Lockout (1 red flash for start-up, 4 red flashes for during operation)
Possible Cause
Manual gas valve not open
Air in the gas line
Supply gas pressure too high or too low
Loose wire connections
No Spark:
a. Spark electrode
b. Spark cable shorted to ground
c. Ignition controller not grounded
High Limit Control tripped
Faulty combination valve
Faulty ignition control
Valve Circuit Error (3 red flashes)
Check that the valve is a 24 volt AC valve. Check that the valve is wired correctly.
Internal Control Error (7 red flashes)
Check all ground connections including the entire unit.
Line Frequency/Voltage Error (solid red)
Check that the controller power is 24 volt AC (+10%/-15%). Check for 60 Hz or 50 Hz.
If all checks have been made using the troubleshooting guide and you have confirmed there are no other defective components, and the red
LED error light is flashing or on, then the ignition controller may need to be replaced.
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Open manual valve. If combination valves are used, verify that switch on top is in
"ON" position.
Bleed gas line.
Check that supply pressure is between 6 and 14 in. wg for natural gas and between
11 and 14 in. wg for LP gas.
Check for tight wire connections.
Ensure spark gap is 1/8 inch and ceramic insulator is not cracked. Replace if
necessary.
Replace spark cable.
Ground ignition controller.
Check unit airflow and manifold pressure.
Measure voltage between terminals MV and Common. If 24 volts is present but valve
remains closed, replace valve.
Check diagnostic LED on controller for "steady on". If LED remains on constantly and
there is NO voltage between valve and round, replace ignition controller.
Due to our policy of continuous product innovation, some specifications may change without notification.
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Solution