Vaisala LT31 - Blower System Maintenance

User's Guide ______________________________________________________________________
198 _________________________________________________________________ M210667EN-C
- Change to the advanced level (LEVEL 1 command)
- Enter the CALIBRATE WINDOW_CLEAN LM command
- Leave the LT31 command mode (CLOSE command)
For details, refer to LM21 User's Guide. For details on the LT31
command mode, see Chapter 5, Operation, starting from page 145.
NOTE
There must not be any objects in front of the sensor when the
CALIBRATE WINDOW_CLEAN LM command is given.
NOTE
The window must be dry before giving the CALIBRATE
WINDOW_CLEAN LM command.
Inspection and Cleaning Winter Dirt
The periodic maintenance includes an inspection and cleaning of all the
system component housings of the transmissometer.
1. Use a soft cloth and warm water with a household cleaning agent
and clean especially the following:
- Measurement head covers of the transmitter and receiver
- Masts and interface unit covers
- PWD Sensor housing parts
- Housing of the optional Background Luminance Sensor LM21
- Optional Obstruction Light LT31OBS
2. During the cleaning, check all the housing surfaces for mechanical
damages.
Blower System
The LT31 transmitter and receiver are equipped with a blower system.
The blowers are controlled by the master CPU software. By default, the
blowers are switched on continuously. An air duct on top of each
measurement unit lead the blower air stream towards the window area.
In the frame of the periodic maintenance, the operation of the blowers
should be checked. The cleanliness of the particle filters should also be
checked, and the filters should be changed if necessary. See instructions
in the next pages.