Help and Documentation

Welcome to the LI-840 CO2/H2O Analyzer help and documentation.


LI-840 CO2/H2O Gas Analyzer Instruction Manual

Instruction manual for the LI-840 CO2/H2O Gas Analyzer.

Instructions for using the CalAdjust application

Instructions for using the CalAdjust application in older LI-820s, LI-840s, and LI-8100s. Not for new LI-820s, LI-840As, or LI-8100As.


LI-840 CO2/H2O Analyzer Instrument (Embedded) Software v1.0.15

Instrument (embedded) software v1.0.15 for the LI-840 CO2/H2O Analyzer.

LI-840 CO2/H2O Analyzer Windows Interface Software v1.0.2

Windows interface software v1.0.2 for the LI-840 CO2/H2O Analyzer.

Frequently Asked Questions

All Documents


Measuring pCO2 and Dissolved Inorganic Carbonates in Water

Application note that describes how to use LI-COR analyzers in systems that measure the partial pressure of CO2 (pCO2) and dissolved organic carbonates in water.

application note
Communicating with LI-COR instruments using LabVIEW Basic instructions that describe how to communicate with LI-COR instruments using LabVIEW. Includes sample programs to read data. application note

LI-820/LI-840 Gas Analyzers: installation instructions for embedded software

Instructions for updating the embedded (instrument) software in the LI-820 CO2 or LI-840 CO2/H2O Analyzers.

install guide

LI-840 Source/Detector Replacement Instructions

Replacement instructions for the source and detector of the LI-840 CO2/H2O Gas Analyzer.

install guide

Source, Detector, and Optical Path Replacement Instructions

Instructions for replacing the source, detector, and optical path in the LI-800, LI-820, LI-840, and LI-8100A gas analyzers.

install guide

Frequently Asked Questions About Replacing LI-840 Source and Detector

Frequently Asked Questions about replacing LI-840 source and detector.

tech tip

LI-840 Factory Recalibration

Recommended Recalibration Frequency: No regular factory recalibration required.

What's included with LI-840 recalibration?

A factory recalibration includes:


  • Analyzer drift and stability is checked.
  • H2O analyzer calibration (6 points, 3 temperatures).
  • CO2 analyzer calibration (17 gas concentrations at 3 temperatures).
  • The accuracy of the calibration function is then verified across the measurement range of CO2 and H2O.

Tests and Maintenance

  • The optical path components and hoses are inspected.
  • Software is updated as needed.
  • Other repairs and maintenance as needed; customers are notified if additional fees are required for repairs.

Request Service and Recalibration

To request factory service or recalibration for a LI-COR instrument: Request Factory Service or Recalibration

Service will be performed at our US office in Lincoln, NE USA, European office (LI-COR Biosciences - GmbH), or by a distributor. To locate your country and designated point of contact click here.

Looking for a Calibration Certificate?