Greenheck DG / DGX with Pilot Ignition (463555 IOM) (Pre-2008) - Manual (Page 22)

22
Start-Up
7
6
0.625 - 0.675 in. wc
Start-Up - Direct Gas
Step 4 Set the Burner Air Pressure
Differential
With the fan running and discharging 70°F air,
connect a U-Tube manometer to the outer sensing
probes (see below) and measure the static pressure
across the burner.
The proper static pressure should be between 0.625
and 0.675 inches w.c. Evenly adjust the baffles above
and below the burner, keeping the burner centered in
the opening until the required pressure is obtained.
Outer Sensing Probes
Adjustable
Top Baffle
Airflow
Burner
Adjustable
Bottom Baffle
IMPORTANT!
Proper air velocity over the burner is critical on direct fired gas units. If the air velocity is not within
the unit specifications, the unit will not operate efficiently, may have sporadic shutdowns and may
produce excessive carbon monoxide (CO) or other gases.
NOTE!
To increase the static pressure decrease the
opening. To decrease the static pressure
increase the opening.
IMPORTANT!
This process may need to be repeated until the
proper pressure is achieved. This adjustment
will change the air quantity delivered by the unit
and therefore the air quantity delivered should be
rechecked. Refer to the blower start-up section.
NOTE!
When required pressure is obtained, be sure to
reconnect the outer sensing probes.
Measuring the Burner Pressure Drop
Burner and Baffles