Vaisala LT31, Руководство пользователя, Страница: 220 / 294

User's Guide ______________________________________________________________________
220 _________________________________________________________________ M210667EN-C
5. After replacing the LTD112 module, close the measurement unit
carefully. Pay attention to the position of the cover seal.
6. The repaired measurement unit must be mounted in the same way
as described in section Mounting Receiver Measurement Unit on
page 124.
7. Make sure that the enclosure is parallel with the support unit.
8. Secure the fastening screws of the measurement unit carefully.
9. Turn on the AC power switch (and also the battery backup switch,
if installed).
CAUTION After repairing the measurement unit, fine alignment and calibration
must be carried out to establish normal operational conditions. For
details, see sections Fine Alignmenton page 231 and Calibrationon page
232.
10. Re-install the measurement head cover and lock it carefully.
11. Close the interface unit and mount the upper interface unit cover
after finalizing fine alignment and calibration.
Replacing Blower Unit LTB111
After approximately five years of operation, the blower units of LT31
need to be replaced. The blower units are identical for the LT31
transmitter and receiver.
To replace a blower unit, the AC power has to be switched off first and
then the measurement head cover has to be removed.
1. Remove the upper interface unit cover and open the interface unit
with the provided key.
CAUTION Make sure to switch off the AC switch before replacing the blower unit.
NOTE In case of the optional LTBB111, switch the battery backup switch off
as well. See Figure 40 on page 83.
2.
Loosen the three lock screws at each side of the measurement head
cover and carefully remove the cover from the measurement head.
See Figure 95 on page 140.
3. To access the fastening screws of the blower unit, the measurement
unit has to be removed first.