Using the Setback Feature
(continued)
4 Access Screen 27 and set the setback return temperature for the air
exiting the hopper. This screen shows the actual temperature meas-
ured at the hopper outlet and the setpoint temperature for the air at the
hopper outlet that will initiate the control to go into setback.
5 Access Screen 28 and set the setback temperature band. This
screen shows how much lower the hopper outlet temperature must
drop from the Setback Return Temperature setpoint (Screen 27) before
the dryer control should restore the original process setpoint.
Setback Feature Guidelines
Careful selection of setpoint values in these functions is necessary for the
setback to operate properly. The following table is only a guideline of
recommended settings for these setpoints. It will be necessary for each
customer to determine the best setpoints for their application based on
experience.
Normal Setback Return Temp Setback Temp
Drying Temp Screen #27 (Process) Screen #26
160° F {71° C} 120° F {49° C} 150° F {66° C}
240° F {116° C} 135° F {57° C} 180° F {82° C}
300° F {149° C} 160° F {71° C} 200° F {93° C}
340° F {171° C} 180° F {82° C} 220° F {104° C}
Operati on l 4-47