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:
Select a representative location: install the probe where humidity, temperature and pressure conditions are representative of the environment to be measured.
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.
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.
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.
Probe installation (HF73 type Q)
•Type Q for 25mm: use parts AC1303-M (compression fitting) and AC1305 (flange) to hold and seal the probe when mounted through a wall (see Accessories).
•Type Q for 15mm: use parts AC1304-M (compression fitting) and AC1306 (flange) to hold and seal the probe when mounted through a wall (see Accessories).
