Greenheck DGX Installation, Operation And Maintenance Manual page 34

Heater Does Not Operate
Attempts to light but no flame (Visible spark)
Is the low fire set properly
(Direct Gas Start-Up Step #6)
Yes
Check inlet gas pressure.
(Direct Gas Start-Up Step #1)
Gas pressure between the min
and max shown on the direct gas
label?
Yes
Air in the gas line?
No
Check burner pressure drop
(Direct Gas Start-Up Step #3)
Pressure drop across the burner
between 0.60 and 0.675 in. wc?
Yes
Proper spark?
Yes
Troubleshooting
No
(Reference Direct Gas Start-Up Step #6)
No
(Reference Direct Gas Start-Up Step #1)
Yes
No
(Reference Direct Gas Start-Up Step #3)
No
With proper airflow, gas pressure and spark,
If problems remain, consult the factory
34
Adjust the low fire setting
Correct gas pressure
Purge gas line
Adjust burner baffles
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.