Vaisala HMP230 - Manual (Page 10)

HMP230 SERIES
User's Guide
M210225en-B
4
3. INSTALLATION
3.1. Selecting the place of installation
Choose a place which gives a true picture of the environment or process, and
is as clean as possible. Air should circulate freely around the sensor. A rapid
air flow is recommended; it ensures that the sensor head and the ambient air
are at the same temperature.
Install the transmitter in a place where no cold or hot spot can develop. When
the sensor head is installed in a duct or process channel where the temperature
is different from the ambient temperature, insulate the point of entry; this is
particularly important if the transmitter is installed with the sensor head
pointing downwards. Installing the sensor head of the HMP233, HMP234 and
HMP235 vertically is not recommended. An uninsulated installation could
lead to condensation in the sensor head and even when no condensation oc-
curs, the resultant air flow may change the temperature near the sensor and
distort the readings.
Install the sensor head in the process wherever possible; avoid sample flows
where the gas temperature can drop below dewpoint temperature. Install the
sensor head transversely against the direction of the process flow.
In duct or channel installations drill a hole ready for a reference meter. Plug
the reference hole tightly.
Install the electronics housing away from possible steams escaping from the
process.
NOTE
To ensure an IP 65 class protection:
1. Always mount the transmitter housing with the cable
bushings pointing downwards.
2. Make sure that the connection cable has the right
thickness ( ∅ 7...10 mm) and that the cable bushing
is carefully tightened.
3. Pay always special attention to closing the
transmitter cover carefully and remember to tighten
all four screws.