September 2014 - Dryer Alarm Status
Sr. Tech Specialist and Master Trainer
Environmental and Process Monitoring
Meet our techs: Debbie Bowe
When there is a reduction in the performance of the dryer, you will get a dryer alarm status and there are three possible reasons for this:
1. Dryer has reached end of life
The dryer has more than one year of continuous use. The recommended solution is to replace the dryer. We offer a discounted dryer replacement using our exchange program. Contact us by email or call 1 (866) 282-0430, option 2 to order replacement parts.
2. Vacuum pressure is too low
The vacuum pump pressure also supplies the purge flow pressure. A new or fully rebuilt pump should measure about 80% of ambient pressure while operating at 16.7 LPM. When the vacuum pressure is too low, the purge flow pressure is too low, triggering the dryer alarm. The recommended solution is to replace or rebuild the pump in order to restore sufficient pressure. Use the vacuum gauge on the tee supplied with the equipment on the purge outlet line closest to the 8500 for monitoring pressure. The TEOMTM Model 1405DF or 1405F uses an onboard pressure sensor to monitor the vacuum pressure. The vacuum pressure will alarm at 0.400atm.
3. A leak that raises the purge reference
During normal operation, air flows from the outlet of the dryer through the main flow path in both the reference and base positions of the switching valve; back through the main flow controller; out the back of the main flow valve; through the purge side of the dryer; and out to the pump. We regenerate the dry air leaving the dryer through the purge reference. If a small leak is present, air could draw from the shelter with a higher RH percentage. This higher RH percentage will raise the purge reference and reduce the drying performance of the dryer. Over a period of time, the performance declines until eventually the dryer alarm is activated.
If you still have questions on FDMS system dryer alarms, you can email or call 1 (866) 282-0430, option 2.
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