Vaisala HMT330 - Manual (Page 44)

User's Guide _______________________________________________________________________
42 ___________________________________________________________________ M210566EN-K
When there is no alternative but to install the probe in the process
vertically, the point of entry must be carefully insulated. The cable must
also be allowed to hang loosely as this prevents any condensed water
from running onto the probe along the cable.
0507-022
Figure 24 Vertical Mounting of Probe
The following numbers refer to Figure 24 above:
1 = To be sealed
2 = Insulate the cable
3 = To be insulated
4 = Let the cable hang loosely. This prevents condensed water
running to the sensor along the cable.
NOTE Please do not attach a heated probe (HMT337) to metal structures to
avoid condensation problems caused by heat conduction along the metal.
If the process temperature is much higher than that of the environment,
the whole probe and preferably plenty of cable must be inside the
process. This prevents measuring inaccuracy caused by heat conduction
along the cable.
When mounted on the side of a duct or channel, the probe must be
inserted from the side of the duct. If this is not possible and the probe
must be inserted from the top, the point of entry must be carefully
insulated.
For Vaisala probe installation kits and some installation examples, see
Appendix A on page 185.