Troubleshooting

In this section, we describe how to identify some potential problems with the LI-870 and how to resolve them. If you can't find a solution here, if you need further assistance performing maintenance, or if you have other questions, contact your local distributor or LI-COR technical support for more help.

Smart Chamber or LI-8250 software not recognizing LI-870

Power is supplied from the Smart Chamber or LI-8250, and assuming your connection is completed correctly, the gas analyzer is always powered on when the Smart Chamber or LI-8250 is powered on. The Smart Chamber or LI-8250 will automatically recognize your device with no further steps needed. Simply expand the LI-870 drop-down in the Connections menu of the Measurement Settings page of the Smart Chamber or LI-8250 software, select your instrument serial number, and press Update.

If you open the drop-down menu and your instrument does not appear,

  • Is your power cable fully connected to both devices? Make sure the cable is fully inserted and the threaded nut is snugly fastened.
  • Is your USB cable fully connected to both devices? Ensure that the connectors on both sealed cables are clipped to the prongs on each device.

If your cables are fully connected but you still cannot identify your device, you can open your device to see if power is being supplied. Next to the connection panel inside the case, a red LED light will be blinking if power is being supplied.

Note: Do not open the LI-870 enclosure in the field. This can cause the temperature and pressure of the optics to become destabilized. More importantly, this can allow dust and debris into your analyzer. If possible, you should confirm whether your analyzer is working properly and troubleshoot any issues before taking it out to the field.

If your Smart Chamber or LI-8250 is on and your cables are properly connected, the light should be blinking. If it is not blinking, something could be wrong with your power cable, the chamber power-out connector, analyzer power-in connector, or other electronics inside the case. Check for dust and debris in the connectors and for damage to the cable itself. For power-related issues, it is recommended that you call LI-COR technical support for further instructions.

If the light is blinking but you still cannot identify your device through the Smart Chamber or LI-8250 software, check your USB cable for damage. Is there dust or debris in the cable heads or the connectors? Try refreshing the interface software, clearing your browser cache, and rebooting your Smart Chamber or LI-8250. If you still cannot connect, contact LI-COR technical support.

Unable to Zero or Span the Instrument

Is there dirt in the optics? If the optical cell becomes contaminated, the instrument will drift in either the zero or span. See Cleaning the optical bench for details on cleaning your optical bench.

Instrument Reports -50 ppm CO2 or Measurements Jump Around

If the instrument measures -50 ppm or the measurements are going between negative and positive values, or just simply not making any sense, the optical source may have failed or be in the midst of failure. Contact technical support for additional troubleshooting help.

Pump not working

Use the LI-830 and LI-850 software to test connect with the LI-870 and test the pump.

If CO2 and/or H2O do not change as quickly as expected, there might not be adequate flow through the analyzer, which may indicate a failed pump. A simple way to test the pump is to turn it on in the software and exhale near the air inlet. You should see a drastic increase in CO2 concentration within a few seconds. If it takes significantly longer, the pump may not be functioning. You can also check the measured flow rate in the Diagnostics tab of the software. Otherwise, troubleshoot with these steps:

  • Analyzer not warmed up yet?

  • If the heater is enabled, the pump only runs when the optics are warmed up. Make sure that the bench temperature is up to 51 °C. If it never heats up to 51 °C, the optical source or detector may have failed or be on the brink of failure. Contact technical support for additional troubleshooting help.