Start-up - direct gas – Greenheck DG / DGX with Direct Spark (464043 IOM) (Pre-2008) User Manual

Page 22

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22

7

6

0.625 - 0.675 in. wc

Start-Up - Direct Gas

Start-Up

Step 3 Set the Burner Air Pressure

Differential

With all access panels in place, 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 wc. If needed, 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

U-Tube

Manometer

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.

NOTE!

The pressure drop was set at the factory

and may not need adjustment.

Burner and Baffles

Measuring the Burner Pressure Drop

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