ROTRONIC HF4 - Manual (Page 12)

E-M-HF4-V1_22
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
HygroFlex HF4 Humidity Temperature
Transmitters: User Guide Instruction Manual
Document Type
Page 12 of 29
Document title
© 2009-2011; Rotronic AG E-M-HF4-V1_22
5 Mechanical installation
5.1 General guidelines
Relative humidity is extremely dependent on temperature. Proper measurement of relative humidity requires
that the probe and its sensors be at exactly the temperature of the environment to be measured. Because of
this, the location where you choose to install the probe can have a significant effect on the performance of the
instrument. The following guidelines should guarantee good instrument performance:
a) Select a representative location: install the probe where humidity, temperature and pressure
conditions are representative of the environment to be measured.
b) Provide good air movement at the probe: air velocity of at least 200 ft/ minute (1 meter/second)
facilitates adaptation of the probe to changing temperature.
c) Avoid the following: (1) Close proximity of the probe to a heating element, a cooling coil, a cold or
hot wall, direct exposure to sun rays, etc. (2) Close proximity of the probe to a steam injector,
humidifier, direct exposure to precipitation, etc. (3) Unstable pressure conditions resulting from
excessive air turbulence.
d) Immerse as much of the probe as possible in the environment to be measured.
e) Prevent the accumulation of condensation water at the level of the sensor leads. Install the
probe so that the probe tip is looking downward. If this is not possible, install the probe horizontally.
5.2 HF4 enclosure
The HF4 enclosure consists of a base and a cover held together with 4 screws. To open the enclosure, use a
metric 2.5 mm hex key. Prior to re-assembling the enclosure, verify that the red seal is sitting properly in its
groove on the base.
5.3 Installation of the HF4 type D (through wall mount)
Mounting position of the enclosure
Vertical:
HF42 and HF43 type D
without keypad and display Horizontal:
HF42 and HF43 type D with
keypad and display
HF45 type D