Greenheck DG / DGX with Direct Spark (464043 IOM) (Pre-2008) - Manual (Page 24)

24
Start-Up - Direct Gas
Step 6 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 shown below.
After setting the minimum firing rate, reconnect the wire to the modulating valve.
Minimum
firing rate
adjustment
Remove one wire to
send the unit to the
minimum firing rate.
IMPORTANT!
The proper minimum firing rate setting results in
a small ribbon of continuous flame which covers
the flame rod and runs across the entire burner.
IMPORTANT!
The minimum firing rate setting is critical. If the
settings is too high, the unit may not light, too
low and the flame rod may not detect the flame.
IMPORTANT!
Do not allow the disconnected wire to come in
contact with a potential ground, damage to the
amplifier or transformer could result.
Start-Up
NOTE!
Adjusting the maximum and minimum fire may
require the inlet air sensor to be initially set
higher than desired in order to start the
burner(s). Once high and low fire have been set,
the inlet air sensor should be turned down to the
desired temperature.
NOTE!
Counterclockwise rotation increases the
minimum fire rate setting, clockwise rotation
decreases the setting.
Step 5 Set the Maximum Firing Rate
(...continued)
While monitoring the units temperature rise, set the
maximum firing rate by adjusting the regulator until
the designed temperature rise is achieved. After
setting the maximum firing rate, reconnect the wire to
the amplifier.
IMPORTANT!
Setting the maximum firing rate during mild
weather conditions may cause the high limit to
trip out during extreme conditions requiring
manual resetting.
NOTE!
Clockwise rotation increases the temperature rise, counterclockwise rotation decreases the
temperature rise.
NOTE!
The minimum setting for the maximum firing rate may be higher than required. This is acceptable, the
burner will modulate as needed.
Maximum
firing rate
adjustment
Regulator
Modulating Valve