S - 3, Start-up - direct gas, Step 1 check the supply gas pressure – Greenheck DG / DGX Industrial Space Heating (464044 IOM) (Pre-2009) User Manual
Page 11: Important, Step 2 check the pilot gas pressure, Minimum and maximum gas pressures

Step 1 Check the Supply Gas Pressure
Check the supply gas pressure and compare it with the unit’s nameplate pressure requirements (see figure #16).
Adjust the supply regulator as needed until the supply gas pressure is within the specified range.
S - 3
IMPORTANT!
For proper unit function and safety, follow the
start-up procedure in the exact order that it is
presented.
“W.C.
“W.C.
“W.C.
F
PSI
“W.C.
“W.C.
MAX BTU/HR
BTU/H MAX
NORMAL MANIFOLD
PRESSURE
PRESSION D’ADMISSION
NORMALE
MIN GAS
PRESSURE
PRESSION DE GAZ
MIN BURNER
PRESSURE DROP
PERTE MIN DE PRESSION
DANS LE BRULEUR
TYPE OF GAS
NATURE DU GAZ
MIN BTU/HR
BTU/H MIN
MIN GAS PRESSURE
FOR MAX OUTPUT
PRESSION DE GAZ MIN
POUR PUISSANCE MAX
MAX BURNER
PRESSURE DROP
PERTE MAX DE PRESSION
DANS LE BRULEUR
MAX GAS
PRESSURE
PRESSION DE GAZ
MAX
DESIGN ∆T
∆T NORMALE
EQUIPPED FOR
CONCU POUR
SCFM
“W.C.
EXTERNAL STATIC PRESSURE
PRESSION STATIQUE EXTERIEURE
AGAINST
CONTE
Minimum and
maximum gas
pressures
IMPORTANT!
This start-up should begin after all of the
installation procedures and the Electrical
start-up have been completed.
Start-Up - Direct Gas
Step 2 Check the Pilot Gas Pressure
Check the pilot gas pressure. The recommended gas pressure is 3 inches wc. Adjust the pilot regulator as
needed. See the gas train layout in the reference section for the location of the pilot pressure test port and pilot
regulator.
NOTE!
The purpose of the high and low gas pressure switches is to automatically shutdown the burner if the
inlet gas pressure is too low for the burner to safely light, or if the manifold pressure is too high for
the burner to operate safely.
Step 3 Check the Optional High and Low Gas Pressure Switches
Check the settings on the high and low gas pressure switches. The high pressure setting is typically 8 inches wc
and the low pressure is setting is typically 3 inches wc. The switches are set at the factory and should not need
adjustment. Adjust the setting if needed. See the gas train layout diagram in the reference section for the high
and low pressure switch location.
Figure 16.
Direct Gas Nameplate