Grain Systems PNEG-728 - Manual (Page 35)

35
Autoflow Operation
When the Top Dry is in a ready state; that
is, with no grain in the Drying Chamber and wet
grain in the Wet Storage Tank, Fill System #1 and
Fill System #2 will start to fill the Drying Chamber
with wet grain when the start switch is pressed on
the Dryer Control Panel. In single fill system
units only Fill System #1 will start. When grain
reaches the Drying Chamber Low Level Rotary
Switch the Aeration Fan , and the Master Drying
Fan will come on, and the Fan Delay will start to
count down. When the Fan Delay reaches zero the
Slave Drying Fan will start, the Airswitch will
close, and the Dry Timer will start to count down.
In single fan units the Fan Delay will not count
down and the Airswitch will close after the Master
Drying Fan starts. After twenty second Purge
Delay the fan/heater unit(s) will ignite. When the
Plenum Temperature reaches the Cycle Setpoint on
the Hi-Lo Thermostat the fan/heater unit(s) will
cycle to Low-Fire. When the Plenum Temperature
falls ten degrees below the Cycle Setpoint the fan/
heater unit(s) will cycle back to High-Fire. The
fan/heater unit(s) will continue to cycle throughout
the drying process.
When grain reaches the Chamber High
Level Rotary Switch the Load Delay will begin to
count down. When the Load Delay reaches zero
Fill System #2 will shut off and the Aux. 1 Delay
reaches zero Fill System #1 will shut off. If grain
does not reach the drying chamber high level
rotary switch before 2/3rds. of the dry cycle is
complete the fill systems will shut off automati-
cally.
If the Chamber High Level Rotary Switch
becomes exposed due to shrinkage of grain in the
Drying Chamber, the fill system(s) will start and
refill the Drying Chamber. When grain reaches
the Chamber High Level Rotary Switch the fill
system(s) will shut off after the delays.
When the Dry Timer reaches zero and the
Grain Temperature Setpoint on the Moisture
Control Thermostat has not been reached, the unit
will go into Temperature Hold. When the grain
temperature reaches the Grain Temperature
Setpoint on the Moisture Control Thermostat the
unit will continue to the Cool Cycle. In the Cool
Cycle the burner will shut off, the Cool Timer will
begin to count down, and the main drying fans will
continue to run, cooling the grain. When the Cool
Timer reaches zero the dryer will continue to the
Dump Cycle. In the Dump Cycle the main drying
fans will shut off, the Linear Actuator in the
Actuator Control Box extends, the dump chutes
lower, and grain is dumped from the Drying
Chamber into the Storage Chamber. Immediately
after the dump chutes open, the Unload Timer
begins to count down. When the Unload Timer
reaches zero the dump chutes raise. During the
Dump Cycle all of the grain is dumped into the
Storage Chamber.
After the Dump Cycle the unit returns to
the beginning of the Dry Cycle, the Out of Grain
Timer begins to count down, the fill system(s)
refill the Drying Chamber and the process begins
again. If grain does not reach the Drying Chamber
Low Level Rotary Switch before the Out of Grain
Timer reaches zero, the dryer will give an “Out of
Grain” error and shut down. If the Dry Timer
reaches zero after the grain temperature reaches
the Grain Temperature Setpoint on the Moisture
Control Thermostat the unit does not enter Tem-
perature Hold. If goes right to the Cool Cycle.
The unit continues with the same operation
until either no grain is present against the Wet
Supply Rotary Switch, or the Storage Chamber
becomes full.
If the Wet Storage Tank becomes empty
while the fill system(s) are running, the Unload
Delay start to count down. When the Unload
Delay reaches zero the fill system(s) shut off along
with the dryer and a “Wet Supply Hopper Empty”
error is displayed on the Dryer Control Panel
screen. If there is grain against the Drying Cham-
ber Low Level Rotary Switch the unit can be
continued on page 36
THEORY OF OPERATION