Changing Filter - DMT132

DMT132 User Guide

Document code
English (United States)
Document type
User guide

If the filter is contaminated, it should be replaced. New filters can be ordered from Vaisala (order code 230602). Be careful when changing the filter, since it is easy to break the sensors when the filter is removed.

CAUTION If the transmitter is installed in a pressurized chamber, always make sure that the pressure of the chamber is equalized with the ambient pressure prior to removing the transmitter. When the transmitter is removed for maintenance, cap the hole with a capped nut. This way, the process can be running although the transmitter is not in place. Plugs are available from Vaisala for ISO threaded connections (Vaisala order code 218773) and NPT threaded connections (Vaisala order code 222507).

When replacing the filter, note the following:

  • Touching the filter with your fingers will also deposit oil and dirt on the filter, which may affect the measurement. Always handle the filter with gloved hands.
  • When installing the transmitter after a filter change, inspect the sealing ring first. Use a new one if the old ring is visibly damaged.
Figure 1. Opening the Filter
Figure 2. Filter Structure
Sealing ring (replace if damaged)
Vaisala HUMICAP® 180R sensor and Pt1000 temperature sensor
Spring washer
Tube filter

Replace the filter as follows:

  1. Turn the filter counterclockwise until it is loose.
  2. Pull the filter straight out carefully; do not damage the sensors, and do not lose the spring washer.
  3. Take the new filter, and insert it to the filter threads. The spring washer should be under the filter. A new washer is not included with the filter, so reuse the old one.
  4. Tighten the new filter by turning it clockwise. Do not use tools to tighten the filter, finger tightness is enough.