Troubleshooting
8:1 Staged Furnace Will Not Light
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With the combustion blower |
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(CM) on for at least | No |
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30 seconds, is there |
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24 VAC across T and A or E? |
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| Yes |
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Ignition controller (IC#) | Yes |
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red LED |
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blinks 7 times or is on |
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| No |
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Ignition controller (IC#) | Yes |
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red LED blinks |
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1 time, 2 times or 4 times |
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| No |
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Cycle power to the unit |
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and wait 30 seconds |
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Does the combustion relay | No |
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(R9 or CR) close? |
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| Yes |
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Does the combustion | No |
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blower (CM) run? |
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| Yes |
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Does the combustion | Yes |
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blower stop after |
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30 seconds of operation? |
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| No |
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Everything is working properly, |
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consult factory. |
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Furnace controller (SC1) defective
Replace furnace controller (SC1)
Ignition controller(s) (IC#) failed
Replace faulty ignition controller(s)
Improper manifold pressure
Set high and low manifold pressure (refer to 8:1 Staged
Faulty spark rod or spark gap does not equal 1/8 inch
Replace spark rod or adjust gap to 1⁄8 inch
Internal high limit tripped (temperature above set point)
Let temperatures cool
Internal inlet air sensor open
Adjust inlet air sensor setting (refer to 8:1 Staged
Combustion relay (R9 or CR) defective
Replace defective combustion relay (R9 or CR)
Combustion blower fuse (FU9) blown
Replace combustion blower fuse (FU9)
Combustion blower (CM) defective
Replace defective combustion blower (CM)
Airflow switch (PS2) defective
Replace defective airflow switch (PS2)
Airflow relay (R9) defective
Replace defective airflow relay (R9)
®
Model IG / IGX
