Troubleshooting l 6-15
Setback
The setback function available on the DC-1 Dryer is designed to save you money
on energy costs and keep you from over drying your material. Setback is available
as separate options on both the temperature and load rate setting.
This is how setback operates when the control setback is set to "On" on
"Temperature" (Screen 24) (optional on DC-1 controls).
The control monitors the temperature of the air exiting the drying hopper. If that
temperature reaches a customer entered setpoint (Screen 10), the delivery process
air temperature will automatically set back to a customer-entered set point
(Screen 11). Then, if the air exiting the drying hopper drops below the customer-
entered temperature on Screen 10 by an amount greater than what is shown on
Screen 22, the process temperature will automatically reset back to the original
process temperature (Screen 5).
This is how setback operates when the control setback is set to "On" on the
"Load Rate" option screen (Screen 25) (optional on DC-1 controls).
When operating the setback option on the load rate setting, the control counts how
many times the loader attempts to load. The load rate setting tells the dryer to go
into setback when the load rate reaches its set number of loads per hour
(Screen 12). If the load rate drops below the customer-entered setpoint
(Screen 12), the delivery process air temperature will automatically set back to the
original process temperature (Screen 5).
To set-up setback on the temperature option
1 Reference the flow chart on Page 4-4 and follow the menu tree path to
access Screen 24.
2 Turn the setback function for the temperature option to "On" or "Off".
"Off" turns the setback mode off, and the dryer will not change the process set-
point. "On" tells the control the dryer should go into setback when the hopper
outlet temperature reaches its setpoint (Menu 6, Screen 10).
3 If you have decided to turn the temperature setback to "On", go to Screen
10. This is where you will set the temperature setpoint for the air at the outlet
of the drying hopper. When this setpoint is reached, the dryer will automatical-
ly change the process setpoint to the setpoint shown on Screen 11. When the
temperature at the outlet of the hopper drops below the setpoint by the value
shown on Screen 22, the dryer will return to the normal drying setpoint
(Screen 5).
Central
When supplied for central
drying applications, the D
series dryer is not equipped
with a process heater.
Therefore the Setback func-
tion is not applicable.