Precipitator Troubleshooting

Most problems are identified by an alarm.
All alarms should be proven/verified and addressed.

The common ESP problems and causes are as follows:

Symptom	Cause	Solution
Under voltage trip or low voltage	Full hopper Broken, tracking or cracked insulator Internal electrode misalignment	Make sure hoppers are empty Make sure ash removal system is working properly Clean and inspect all insulators, replace any broken or cracked insulators (outage) Check all collector plates and discharge electrodes for proper alignment Make sure no collector plates and discharge electrodes are bowed or bent (outage) Contact HRC for inspection
Low ESP electrical readings	Full hopper Broken, tracking or cracked insulator Internal electrode misalignment Excessive gas volume or loading to ESP Rappers not working	Follow above procedures plus: Check and verify all process conditions Make sure all rappers are working Contact HRC for site visit and evaluation
Overload trips (H.V. controls)	Excessive ESP sparking Shorted SCR in controller Faulty gate signal to SCR	Note ESP sparking and, if excessive, lower operating level Check control and SCR and firing circuit Contact HRC for service visit
Heavy build up on collector plates and/or discharge electrodes	Improper or poor rapping sequence Rappers are not working Damaged or broken rapper shafts Moisture/condensation Change in process conditions Low operating temperatures	Optimize rapping sequence Repair any defective rappers or rapper controls Repair any broken rapper shafts Note and correct any moisture conditions (i.e., corrosion, boot seals etc.) Review process conditions Check flue gas temperatures Contact HRC for inspection and evaluation
High stack opacity/high outlet emissions	Excessive gas volume or loading to the ESP Low power levels in ESP Poor rapping	Check process conditions Review ESP electrical readings Check for proper rapper operation Contact HRC for evaluation
Stack “puffing”	Improper or poor rapping High velocity zones in ESP	Check and optimize rappers Check for pluggage on gas flow distribution devices Contact HRC for inspection and possible flow study