STT40 / STT70
Problem | Possible cause | Corrective action | |
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| Process heaters are faulty. | Check for open heaters. Replace | |
| if required. | ||
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| Replace. | ||
Loss or reduction of process air | controller faulty. | ||
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| Make sure that plant personnel | ||
temperature. |
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Process temperature was | are aware of the proper | ||
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| adjusted in error by plant | temperature set point. Post an | |
| personnel. | appropriate sign next to the | |
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| controller. | |
| Process heaters are faulty. | Replace. | |
| Desiccant beds are | Replace desiccant. | |
| contaminated. | ||
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| Drying systems are designed for | |
| Material being dried differs | the material which was | |
| originally specified. Different | ||
| from material specified at the | ||
| materials may need a longer | ||
| time of purchase. | ||
Loss or reduction in drying | residence time or a different | ||
| |||
| drying temperature. | ||
capacity. |
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Break in flex hose to/from | Inspect for air leaks; replace as | ||
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| drying hopper. | needed. | |
| Airflow valve sticking or failing | Check for proper operation of | |
| valve actuators. Repair or | ||
| to shift. | ||
| replace if necessary. | ||
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| Blower fins filled with dust or | Remove blower side plate, | |
| clean baffles, replace. | ||
| contaminants. | ||
| Replace filter elements. | ||
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| Insufficient power to PLC | Check power supply and power | |
PLC Regeneration Bed LED | (Power LED is off). | wiring to PLC. | |
Faulty PLC (PLC Power light is |
| ||
indicators both off. | Replace PLC. | ||
on, Run light is off, and/or Error | |||
| |||
| light is on). |
| |
| Regenerating bed cooldown. | None. | |
| Blower Input indicator is off. | Verify that blower contactor is | |
| on. Check input wiring to PLC. | ||
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PLC Regeneration Heater | Process air in | None. | |
condition. | |||
Left/Right output indicators both |
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Insufficient power to PLC | Check power supply and power | ||
off. | (Power light is off). | wiring to PLC. | |
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| Faulty PLC (PLC Power light is | Replace PLC. | |
| on, Run light is off, and/or Error | ||
| light is on). |
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Troubleshooting