Detcon TP-624D - Manual (Page 37)

Model TP-624D
TP-624D Instruction Manual Rev. 0.4 Page 33 of 40
Stability Fault
Probable Causes: Failed Sensor, empty or close to empty Cal Gas Cylinder, problems with cal gas and
delivery, or no Humidifying Tube used, failure to properly desiccant packet the sensor cell during extended
power-off periods.
Check Heater Power Setting (should be 240 ± 5mW at 25ºC ambient temperature).
Verify use of span gas Humidifying Tube.
Check validity of span gas using H
2
S pull tube or other means (check MFG date on cal gas cylinder).
Check for obstructions through stainless steel flame arrestor (including being wet, blocked, or corroded).
Replace the H
2
S sensor.
Clearing Fault
Probable Causes: Failed Sensor, Cal Gas not removed at appropriate time or problems with cal gas and
delivery, presence of background H
2
S, or incorrect Heater Power Setting.
Must recover to < 8ppm in < 5 min after AutoSpan is complete
Use bottled air (zero air) if there is a known continuous H
2
S background level.
Verify use of span gas Humidifying Tube.
Check validity of span gas using H
2
S pull tube or other means (check MFG date on cal cylinder).
Check for obstructions through stainless steel flame arrestor (including being wet, blocked, or corroded).
Perform Heater Power Setting.
Replace the H
2
S sensor.
Poor Calibration Repeatability
Probable Causes: Failed Sensor, use of wrong Cal Gas or problems w/ cal gas and delivery, or Interference
Gases
Check for adequate Sensor Life.
Check Heater Voltage Setting (should be 240±5mW at 25ºC ambient temperature).
Verify use of span gas Humidifying Tube.
Check validity of cal gas using H
2
S pull tube or other means (check MFG date on cal cylinder).
Check for obstructions through stainless flame arrestor (including being wet, blocked, or corroded).
Evaluate area for presence of any contaminating gases as listed in Section 2.3.
Note the sensor’s serial # and report repetitive problems to Detcon’s Repair Department.
Replace the H
2
S sensor.
Unstable Output/ Sudden spiking
Possible Causes: Unstable power supply, inadequate grounding, or inadequate RFI protection
Verify Power source is stable.
Verify field wiring is properly shielded and grounded.
Contact Detcon to optimize shielding and grounding.
Add Detcon’s RFI Protection Circuit accessory if problem is proven RFI induced.
Nuisance Alarms
Check condulet for accumulated water and abnormal corrosion on terminal blocks.
If nuisance alarms are happening at night, suspect condensation in condulet.
Add or replace Detcon’s
Condensation Prevention Packet P/N 960-202200-000.
Investigate the presence of other target gases that are causing cross-interference erroneous readings.
Determine if cause is RFI induced.
Processor and/or Memory Faults
Recycle power in attempt to clear problem