Loss or reduction in drying
capacity. (Cont’d.)
Airflow valve sticking or
failing to shift.
Check for proper operation of
valve actuators. Repair or
Blower fins filled with dust or
contaminants.
Remove blower side plate,
clean baffles, replace.
PLC Regeneration Bed LED
indicators both off.
Insufficient power to PLC
(Power LED is off).
Check power supply and
power wiring to PLC.
Faulty PLC (PLC Power light
is on, Run light is off, and/or
Replace PLC.
PLC Regeneration Heater
Left/Right output indicators
both off.
Regenerating bed cool down.
Blower Input indicator is off.
Verify that blower contactor is
on. Check input wiring to
Process air in high-
temperature condition.
None.
Insufficient power to PLC
(Power light is off).
Check power supply and
power wiring to PLC.
Faulty PLC (PLC Power light
is on, Run light is off, and/or
Replace PLC.
Material in drying hopper
cakes, or meltdown occurs.
Process temperature set too
high due to operator error.
Check resin manufacturer’s
data sheet for proper drying
temperature. Make sure plant
personnel are aware of the
correct process temperature
High temperature alarm not
set properly.
Reset high temperature
alarm.
Process set point is out of
acceptable range.
Restore temperature
controller to factory pre-sets.
Celsius (ºC), set point at
Verify correct Celsius or
Fahrenheit settings.
Poor dew point performance.
Burned out regeneration
heater.
Repair or replace.
Contaminated or worn out
desiccant.
Replace.
Leaking process air hoses.
Dryer operates beyond its
capacity.
Check dryer and drying
hopper sizing.
Fouled dew point sensor
manifold.
Clear obstruction. Air should
flow freely through sensor.
Troubleshooting 58
