Grain Systems PNEG-1851 - Manual (Page 80)

Appendix A: Grain Drying Operations
Table A-3 Description of the burner modes
Mode Description
High/low
Starting on high fire, when the plenum temperature exceeds the plenum temperature setpoint plus
the burner differential setting, the burner switches to low fire. Similarly, when the plenum tempera-
ture drops below the plenum temperature setpoint minus the burner differential setting, the burner
switches back to high fire. High/low mode is the default setting.
On/off
Starting on high fire, when the plenum temperature exceeds the plenum temperature setpoint plus
the burner differential setting, the burner shuts off. Similarly, when the plenum temperature drops
below the plenum temperature setpoint minus the burner differential setting, the burner reignites
and switches back to high fire.
Auto
The burner operates in high/low mode until one of the two following scenarios occur: if the burner
remains in low fire for more than 60 seconds, or the plenum temperature exceeds the plenum tem-
perature setpoint by 20°F (11.1°C) for more than 10 seconds, the burner automatically switches to
on/off mode.
Examples
• High/low: Let’s assume that you enter a plenum setpoint of 210°F and a burner differential value of
+/- 1°F. On high fire, when the plenum’s actual temperature reaches 211°F, the burner switches to
low fire. On low fire, when the plenum’s actual temperature drops to 209°F, the burner switches back
to high fire.
• On/off: Let’s assume that you enter a plenum setpoint of 210°F and a burner differential value of +/-
1°F. On high fire, when the plenum’s actual temperature reaches 211°F, the burner shuts off. With the
burner off, when the plenum’s actual temperature drops to 209°F, the burner reignites and switches
back to high fire.
• Auto: Let’s assume that you enter a plenum setpoint of 210°F and a burner differential value of +/- 1°
F. In auto mode, the burner operates in high/low mode until one of the following two scenarios forces
it to switch to on/off mode: (1) If the burner is in low fire and the plenum’s actual temperature remains
below 211°F for more than 60 seconds, the burner switches to on/off mode and high fire ignites; (2) If
the plenum’s actual temperature reaches 230°F, the burner switches to on/off mode and shuts off.
Tip
To ensure uniform drying between the front and rear of the dryer, the burners should switch between high
fire and low fire twice per minute, on average. Start with the default setting (high/low), and select another
mode if the plenum cannot reach its temperature setpoint, or if the burner is not switching between high
fire and low fire at least once per minute. To select a burner mode, click System→Dry (Advanced)→-
Burner Mode.
Grain Drying: Full-Heat or Dry and Cool
Regardless of the chosen drying mode (continuous flow or staged batch), you can choose to dry grain in
full-heat or dry and cool. These operations are not actual selections, but drying methods that are actuated
via the fan and heater switches.
Full-heat allows you to discharge uncooled, hot grain whose moisture content is above its target, and then
manage the grain cooling process outside the confines of the dryer. To operate your dryer in full-heat,
regardless of the mode, make sure that all Fan and Heater switches on the control panel are set to On.
Conversely, dry and cool allows you to completely dry and cool the grain within the dryer and, in doing so,
unload dry grain that is relatively close to its target moisture content for storing. To operate your dryer
using dry and cool in continuous flow mode, make sure that the bottom Fan switch is set to On and the
Heater switch is set to Off. In staged batch mode, the Fan and Heater switches must be set to Auto.
80 PNEG-1851 Vision N2