LI-COR LI-600 - Page 92

Section 8. Maintenance
8-13
10 Power on the internal pump.
Select RH Zero then click Begin RHZero Cal-
ibration to view the RH Ref and RH Sample. Click
TURNPUMP ON.
11 Dry the RH sensors.
Wait for RH to stabilize at ±1% then select Zero in
the computer software. If trending down, zeroing is
not required.
Ensure that the chemicals are fresh, such as Drierite®
(P/N 622-10509), to provide a low dew point.
12 Reinstall all parts in reverse order.
Reinstall the H
2
O buffer material, pump, pump
cover, filter, filter cover, and instrument head shells.
Using a user-supplied airstream
Follow these steps when drying the RH sensors using a
user-supplied airstream from an air tank. Alternatively,
you can use a user-supplied pump and the zero kit (P/N
9968-258) with chemicals to dry the RH sensors. If using
an external pump with the zero kit, ensure that the
chemicals are fresh, such as Drierite, to provide a low
dew point.
Using an airstream in the RH sensor zeroing process
requires the least disassembly.
1 Prepare the LI-600.
Power on the instrument.
2 Open Instrument Calibration.
Connect the LI-600 to a computer via USB then open
the computer software. Click the drop-down menu
on the Toolbar then select Instrument Calibration.
3 Power off the pump.