Greenheck DG / DGX with Pilot Ignition (463555 IOM) (Pre-2008) - Manual (Page 25)

25
Start-Up - Direct Gas
Step 7 Set the Minimum Firing Rate
Disconnect and isolate one of the wires running to the
modulating valve to send the unit to its minimum
firing rate. Set the minimum firing rate by adjusting
the needle valve as shown in the figures below.
After setting the minimum firing rate, shut off the pilot
to ensure that the flame safeguard can still read the
main flame signal. Reconnect the wire to the
modulating valve and open the pilot shut-off valve.
Remove one wire to
send the unit to the
minimum firing rate.
Minimum
firing rate
adjustment
Remove one wire to
send the unit to the
minimum firing rate.
NOTE!
Gas trains are equipped with either separate regulators and modulating valves or with a combined
modulating regulator.
NOTE!
On units with a 42 inch or greater burner, the flame safe guard will automatically shut off the pilot
after the burner has been ignited.
IMPORTANT!
The proper setting for the minimum firing rate
results in a small ribbon of continuous flame
across the entire burner.
IMPORTANT!
Do not allow the disconnected wire to come in
contact with a potential ground, damage to the
amplifier or transformer could result.
NOTE!
Adjusting the maximum and minimum firing rate requires the inlet air sensor to be set higher than the
outdoor air temperature in order to start the burner(s). Once high and low fire have been set, the inlet
air sensor should be set to the desired temperature.
NOTE!
Counterclockwise rotation increases the
minimum fire rate setting, clockwise rotation
decreases the setting.
Separate Regulator and
Modulating Valve Combined Modulating
Regulator
Minimum firing rate
adjustment
Start-Up