Replacing standard hoods with enhanced weather protection hoods - LT31

LTEH211-230 and LTEH211-115 Installation Guide

Document code
Document type
Spare part manual
User guide
These instructions are for mounting enhanced weather protection hoods on both the receiver site and the transmitter site.
  • Ladder
  • Allen key, 3 mm and 4 mm
  • Spanner, 8 mm
  • Crosshead screwdriver
  1. Switch off the AC (mains) power in the interface unit.
  2. If the battery backup LTBB111 is installed, switch off the battery switch.
  3. To remove the white measurement head cover, open the 3 lock screws both on the right and left side of LT31.

    Use a ladder to access the lock screws.

    WARNING To avoid injuries and to avoid damaging the instrument, do not place a ladder or similar against the instrument.
  4. To remove the standard weather protection hood from the support unit, remove the 2 screws (hex socket head, size 3) at each rear end corner of the hood and remove the hood.
  5. Remove the 4 spacers from the support unit.
  6. To remove the measurement unit from the mast, disconnect the electrical connector from the measurement unit and loosen the 2 fastening screws (hex-socket, size 4) on the right side of the measurement unit.

    The fastening screws are accessible through the mast adapter of the support unit. Pull the measurement unit off the mast.

  7. Remove the old cover plate from the measurement unit and mount the delivered cover plate with the adapted air duct.
    Make sure that no dust, dirt, or moisture can enter the measurement unit enclosure while it is open. Vaisala recommends opening the measurement unit in a dry room.
  8. Close the measurement unit carefully. Pay attention to the position of the cover seal. Tighten the measurement unit cover screws firmly to prevent dust or moisture entering the measurement unit during operation in the field.
    Do not reinstall the measurement unit yet.
  9. To install the enhanced weather protection hood assembly, mount the hood and attach it firmly to the support unit with the 4 countersunk head screws included in the delivery.