Vaisala HMT330 - Manual (Page 152)

User's Guide _______________________________________________________________________
150 __________________________________________________________________ M210566EN-K
Changing the Sensor
NOTE When replacing the sensor, the new sensor must be of the same type as
the old sensor (for example, HUMICAP180R). The sensor type can only
be changed at a Vaisala Service Center. Information on Vaisala sensors
is available online at
www.vaisala.com/sensorinfo .
Changing HUMICAP180 and HUMICAP180R humidity sensors is
simple. If the transmitter has the chemical purge and/or warmed probe
option which utilize the HUMICAP180C or HUMICAP180RC sensor,
the change is more difficult as soldering is required to attach the pins of
the integrated temperature sensor element. Vaisala recommends that you
leave the replacement of HUMICAP180C and HUMICAP180RC sensors
to Vaisala Service Centers, but spare parts are available if you want do it
yourself. Soldering instructions are not provided.
Changing the sensor should be considered corrective maintenance, and it
is not necessary in normal operation. If the accuracy of the transmitter
does not seem to be within specification, it is more likely that the
transmitter is in need of calibration and adjustment, and not sensor
replacement. Refer to chapter Calibration and Adjustment on page 155.
To replace the HUMICAP180 or HUMICAP180R sensor:
1. Remove the filter from the probe. See the instructions in section
Changing the Probe Filter on page 149.
2. Remove the damaged sensor and insert a new one. Handle the new
sensor by the plastic socket. DO NOT TOUCH THE SENSOR
PLATE.
3. Perform a calibration and adjustment as instructed in section
Relative Humidity Adjustment after Sensor Change on page 161.
4. Attach a new filter on the probe. When using the stainless steel
filter, take care to tighten the filter properly (recommended force
5 Nm).
0508-079
1 = Pull out the sensor
2 = Plastic socket
Figure 75 Changing the Sensor