Detcon IR-642 - Manual (Page 22)

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
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.
5. Check for unstable power supply.
6. Check for inadequate grounding.
7. If correlates with radio communications then use Detcon RFI filter accessory.
8. Contact Detcon for assistance in optimizing shielding, grounding, and RFI protection.
Excessive Span Drift or Slow Response
1. Verify correct cal gas flow rate and proper use of the cal gas adapter.
2. Check validity of cal gas via the expiration date and use pull tube if necessary.
3. Check for obstructions through s/s sinter element (including being wet).
4. Replace plug-in sensor if Optics Life is <25%.
Drifting Zero
It may be the correct reading if there are real gas leaks or the sensor was zero calibrated when actual gas was present and subse-
quently cleared.
1. Recalibrate zero using target gas “free” sample.
2. Replace plug-in sensor if Optics Life is <25%.
3.15 S PARE P ARTS L IST
613-010000-000 Sensor rain shield
613-120000-000 Sensor splash guard
943-000006-132 Threaded Calibration Adapter
390-000088-000 IR sensor housing assembly (plug-in detector PN370-365878-111 or 370-287724-232,
not included)
370-365878-111 Field replaceable optical plug in sensor (for .3 to 5% range)
370-287724-232 Field replaceable optical plug in sensor (for 10 to 100% range)
926-405500-RANGE IR-640 Plug-in control circuit
926-425500-RANGE IR-640 Plug-in control circuit
500-002042-000 IR Connector board
327-000000-000 Programming Magnet
897-850800-000 3 port enclosure less cover
897-850700-000 Enclosure glass lens cover
960-202200-000 Condensation prevention packet (replace annually).
Detcon Model IR-640/IR-642 Carbon Dioxide Sensor PG.22