Heater Does Not Operate (Direct Spark) - Greenheck VSU Installation, Operation And Maintenance Manual

Troubleshooting

Heater Does Not Operate (Direct Spark)

Attempts to light, but no flame (Visible spark)
Is the low fire set properly?
Reference: Start-Up - Direct Gas,
Set the Minimum Firing Rate, pg. 17
Yes
Check inlet gas pressure.
Reference: Start-Up - Direct Gas,
Check the Supply Gas Pressure, pg. 15
Gas pressure between the
minimum and maximum shown
on the direct gas label?
Yes
Air in the gas line?
No
Check burner pressure drop
Reference: Start-Up - Direct Gas, Check the
Optional High and Low Pressure Switches, pg. 15
Pressure drop across the burner
between 0.625 and 0.675 in. WC?
Yes
Proper spark?
Yes
30 Model VSU Make-Up Air
No
No
Yes
No
Check the Optional High and Low Gas Pressure Switches, pg. 15
No
With proper airflow, gas pressure and spark,
Adjust the low fire setting.
Reference: Start-Up - Direct Gas,
Set the Minimum Firing Rate, pg. 17
Correct gas pressure.
Reference: Start-Up - Direct Gas,
Check the Supply Gas Pressure, pg. 15
Purge gas line.
Adjust burner baffles.
Reference: Start-Up - Direct Gas,
Crossed flame and spark wires.
Uncross wires and reconnect.
Incorrect spark plug gap.
Set spark plug gap to 0.062 in.
Defective spark plug.
Replace spark plug.
the unit should light.
If problems remain, consult the factory.
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