The head and console must be connected with the head cable in order to copy files off of the console using a USB device. The USB device must be formatted as a FAT (File Allocation Table) file system. Power off the instrument, connect the head and console, and try again. Additional file transfer options are described in Transferring files to a computer.

• Symptom: LI-6800 The fluorometer does not output any light no matter the setpoint.
• Possible solution: Be sure the control mode is On and a Setpoint is set.
  
• Symptom: The light output does not change even with a new setpoint value. The system is very sluggish. The LI-6800 also issues frequent warnings about clocks being out of sync and attempting to sync head and console clocks does not help.
• Possible solution: Connect your instrument to a network and restart the instrument. Check to see if you can control the setpoint. If you can, it is likely that the fluorometer clock battery needs to be replaced. See Replacing the fluorometer coin cell battery.

• If the LI-6800 fluorometer does not flash on log, is the Measuring Beam is set to On?
• Change the setting under Fluorometry > Settings > Measuring.
  

• Is the fluorometer set to do 1: FoFm (dark) or FsFm' (light) or 2: FoFm (dark) or FsFm'Fo’ (light) on log under Log Files > Fluorometer Options?
• If it is set to 0: Nothing, no flash will occur upon logging. Also review the Minimum flash interval (if checked) to make sure it is set to a reasonable value. Clear the check box for testing purposes.
  

• Is the fluorometer clock out of sync?
• If the fluorometer clock keeps un-syncing, its clock battery may need to be replaced. See Replacing the fluorometer coin cell battery.

The LI-6800 can use either indicating Drierite^® or silica gel. Indicating Drierite (part number 622-04299) contains cobalt chloride, which can present health risks and is banned in some regions. Therefore, all new LI-6800s are shipped with Sorbead^® Orange CHAMELEON^® as a desiccant (part number 662-16591). You can use either one, but expect some minor differences in the performance of the instrument, which are described below.

Our testing indicates that the instrument's ability to control moisture when using Sorbead will be the same under most circumstances. However, Sorbead adsorbs more CO₂ than Drierite. CO₂ desorption from Sorbead will take longer than from Drierite, and thus CO₂ control may take more time than usual until the CO₂ has desorbed from the silica gel. This may take 15 to 20 minutes of normal operation. This desorption process can be somewhat minimized by leaving the desiccant chemical column on the console when measurements are complete and removing the 8 g CO₂ cartridge from the console when you are finished using the instrument each day.

Yes, Sorbead can be regenerated. Spread the beads into a single layer in a shallow tray. Place it into a 120 °C drying oven for 1 to 2 hours. Then, place the hot beads into a glass jar and tighten the lid. Let it cool. Store the regenerated Sorbead in a glass jar (avoid plastic).

No. Sorbead cannot achieve as low of a dew point as Drierite. Zeroing with tank gas remains the best option. For zeroing H₂O with chemicals, we recommend the following two options for the LI-6800 (we found they yield identical results):

• Use fresh Sorbead in the console desiccant chemical column and fresh Drierite (indicating or non-indicating) in the zeroing column provided with the instrument.
• Use fresh indicating or non-indicating Drierite in the console and zeroing columns.

The Nafion column has two tubes inside. The Stuttgarter Masse column is identical to the H₂O SCRUB and CO₂ SCRUB columns except that the label on the top says H₂O ADD. It may be filled with Stuttgarter Masse.

New Nafion Tubing Humidifier	Older Stuttgarter Masse Humidifier
Two tubes routed around U-shaped guides. Fill with liquid water.	Completely empty if new. Fill with Stuttgarter Masse and <30 mL water. Never use if there is standing water in the column!

We recommend emptying the column when transporting the LI-6800 to eliminate the risk of leaks and condensation.

Remove the Nafion column at the end of each day to prevent humidity from accumulating in the instrument and reduce the risk of condensation. For long-term storage, empty and dry the column and to prevent the growth of mold or algae. Do not expose the column to freezing conditions when there is water in it.

We recommend using white gaskets for the clear top chamber so that if you need to quickly add the 3×3 light source you will not need to change gaskets.