4. If either the left or right bed safety temperature switch opens, a REGEN TEM SAFETY is
generated. The alarm horn and light are activated. The process heater, regen heater, and
process/regen blower are turned off. Pressing the ALARM SILENCE button on the touch screen
will deactivate the alarm horn and light.
5. Turn the Off-On switch to the ON position and push the touch screen START button to restart the
dryer. If the switch is still open, the dryer will not restart.
6. If the PLC/touch screen faults, the optional redundant high temperature safety device opens, or the
process heater safety switch opens, a process heater fault is generated. The alarm horn and light are
activated. The process heater, regen heater, and process/regen blower are turned off. Pressing the
ALARM SILENCE pushbutton will deactivate the alarm horn and light.
7. Turn the Off-On switch to the ON position and push the START button to restart the dryer. If the
fault condition still exists, the dryer will not restart.
8. If the process blower overloads trips, a PROCESS BLOWER FAIL is generated. The alarm horn
and light are activated. The process heater, regen heater, and process/regen blower are turned off.
Pressing the ALARM SILENCE button will deactivate the alarm horn and light.
9. Reset the motor overload and turn the Off-On switch to the ON position and push the START
button on the touch screen to restart the dryer.
10. The valve position limit switch enables the right bed heater and provides an input signal to the PLC
when actuated by the cam lobe. Each heater is controlled by the PLC.
11. Upon completion of the HEAT portion of the regeneration sequence, the regen heaters are disabled
by the PLC and the COOL time begins.
12. Once the COOL time has expired, the valve motor is turned on until the cam switch makes a
transition. Upon making a transition, the timing sequence is restarted for the new bed.
13. When a HIGH DEW POINT alarm is generated by the dew point controller, the alarm horn and
light will activate. Press ALARM SILENCE to deactivate the alarm until the next HIGH DEW
POINT alarm occurs.
14. The dryer is shut off by pushing the SHUTDOWN button on the PLC or turning the control power
On/Off switch to the OFF position.
15. Refer to the schematic drawing enclosed in the control enclosure.
4-3 Shutting Down the Dryer 1 Turn off the conveying system supplying the drying hopper and/or machine. Press the
SHUTDOWN button for the dryer to complete its cycle.
2 When processing is complete, close the hopper slide gate and shut down any in-line companion
equipment, such as the aftercooler.
3 If the dryer is shut down using the SHUTDOWN button on the dryer status screen, the process
heater will shut off and the bed regeneration process will be completed. When the dryer is started at a
later date the process air will be directed through the bed that was regenerated last.
4 If the dryer control switch is turned off without using the dryer shutdown feature, the dryer and the
on board conveying system will stop immediately. When the dryer is started at a later date, the
process air will be directed through the last bed that was being used when the dryer control switch
was turned off. If a bed was being regenerated when the dryer control switch was turned off, the
regeneration process would begin over again on that same bed.
Portable Drying/Conveying Systems Chapter 4: Operation 39 of 63