Detcon FP-624C - Manual (Page 24)

Excessive Span Drift or Slow Response
1. Check Heater Voltage Setting (should be 2.7V C-Style and 2.2V J-Style) and check heater voltage at the sensor if
remote mounted.
2. Verify correct cal gas f low rate and proper use of the cal gas adapter.
3. Check validity of cal gas via the expiration date and use pull tube if necessary.
4. Check for obstructions through stainless steel sinter element (including being wet)
5. Replace plug-in sensor if Sensor Life is < 50%.
6. Check area for presence of sensor poisoning gases such as silicon grease vapors, HMDS, high H2S, chlorine or
chlorinated compounds if sensor failures persist.
Drifting Zero
1. It may be the correct reading if there are real gas leaks or the sensor was zero calibrated when actual gas was
around and subsequently cleared.
2. Check Heater voltage is set correctly for sensor type (check voltage at the sensor if remote mounted).
3. Replace plug-in sensor if Sensor Life is < 50%.
4. If sensor drift is gradual and continuously positive then contact Detcon for sensor replacement.
Unstable Output/ Sudden Spiking/Nuisance Alarms
1. Check condulet for accumulated water.
2. Check transmitter and Terminal PCB for abnormal corrosion.
3. Determine if problem correlates with condensation cycles.
4. Add/change Detcon condensation prevention packet PN 960-202200-000 (replace annually).
5. Check for unstable power supply.
6. Check for inadequate grounding.
7. If correlates with radio communications then use Detcon RFI f ilter accessory.
8. Contact Detcon for assistance in optimizing shielding, grounding, and RFI protection.
Span Calibration Fault – (Sensitivity, Stability, Clearing)
To remove any calibration fault repeat calibration process successfully or unplug/replug transmitter.
Sensitivity - Check Heater Voltage Setting (should be 2.7V C-Style and 2.2V J-Style), Check for obstructions through
stainless steel sinter element (including being wet), check validity and f low rate of cal gas.
Stability - Check Heater Voltage Setting (should be 2.7V C-Style and 2.2V J--Style), check validity and f low rate of
cal gas, Check for obstructions through stainless steel sinter element (including being wet).
Clearing - Must recover to < 10% of range before calibration cycle is complete and returns to normal operation.
Use bottled or fresh air if necessary.
Memory or Error Reports
1. Reinitialize Sensor - Unplug transmitter and replug transmitter then swipe magnet over PGM 1 in the f irst 3 sec-
onds. This will clear the processor and recover from error state. Remember to put in all customer settings for range,
alarm and cal gas level after re-initialization.
Non-readable Display
1. If display has blue background when hot, install sunshade to reduce temperature.
2. If poor contrast, adjust contrast pot accordingly.
Nothing Displayed – Transmitter not Responding
1. Verify condulet has no accumulated water or abnormal corrosion.
2. Verify required DC power is applied to correct terminals.
3. Swap with a known-good transmitter to determine if transmitter is faulty.
Bad 4-20 mA Output or RS485 Output
1. Check that wiring is connected to correct terminal outputs.
2. Swap with a known-good transmitter to determine if transmitter is faulty.
Model FP-624C Combustible Gas Sensor PG.24