| Problem |
| Possible cause |
| Corrective action |
|
|
|
|
|
|
|
|
|
|
| Check resin manufacturer’s data |
|
|
| Process temperature set too high |
| sheet for proper drying |
|
|
|
| temperature. Make sure plant | |
|
|
| due to operator error. |
| personnel are aware of the |
|
|
|
|
| correct process temperature set |
|
|
|
|
| point. |
|
|
| High temperature alarm not set |
| Reset high temperature alarm. |
| Material in drying hopper cakes, |
| properly. |
| |
|
|
|
| ||
| or meltdown occurs. |
| Process set point is out of |
| Restore temperature controller |
|
|
| acceptable range. |
| to factory |
|
|
| Function set for degrees Celsius |
| Verify correct Celsius or |
|
|
| (ºC), set point at degrees |
| |
|
|
|
| Fahrenheit settings. | |
|
|
| Fahrenheit (ºF). |
| |
|
|
|
|
| |
|
|
| Process thermocouple not in |
| Verify that the thermocouple is |
|
|
|
| properly installed in the inlet | |
|
|
| airflow. |
| |
|
|
|
| tube. | |
|
|
|
|
| |
|
|
| Burned out regeneration heater. |
| Repair or replace. |
|
|
| Contaminated or worn out |
| Replace. |
|
|
| desiccant. |
| |
|
|
|
|
| |
|
|
| Leaking process air hoses. |
| Repair or replace. |
| Poor dew point performance. |
| Dryer operates beyond its |
| Check dryer and drying hopper |
|
| capacity. |
| sizing. | |
|
|
|
| ||
|
|
| Bad dew point sensor. |
| Replace. |
|
|
| Fouled dew point sensor |
| Clear obstruction. Air should |
|
|
| manifold. |
| flow freely through sensor. |
|
|
| Dirty filter. |
| Clean or replace filter element. |
|
|
| The internal mechanism is not |
| Properly insert the internal |
|
|
| inserted properly into the |
| |
|
|
|
| mechanism into the housing. | |
|
|
| housing. |
| |
|
|
|
|
| |
|
|
| The power supply is not |
| Properly connect the power |
|
|
| connected to its terminals |
| supply to the power supply |
| Nothing displays when the |
| properly. |
| terminals. |
|
| No power is supplied, or the |
| Supply a voltage of 85 to 125 | |
| controller is turned on. |
|
| ||
|
| supplied power is not within the |
| VAC to the power supply | |
|
|
|
| ||
|
|
| specified range. |
| terminals of the controller. |
|
|
| Disconnect switch or Control |
| Check control power fuse for |
|
|
|
| continuity. Turn disconnect | |
|
|
| Power switch not set to ON. |
| |
|
|
|
| switch and control power switch | |
|
|
| Control Power fuse blown. |
| |
|
|
|
| ON. | |
|
|
|
|
|
Dehumidifying Dryers | Chapter 6: Troubleshooting | 50 of 59 |
