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.
Immerse as much of the probe as possible in the environment to be measured.
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.
Insufficient probe immersion typically creates errors in the measurement of both humidity and temperature and may even cause a malfunction.
•Standard 144 mm probe: this probe is generally not suitable for through wall installation and is designed for full immersion in the environment to be measured. At least 15 to 20” of the probe cable should be inserted together with the probe.
•Optional 294 mm probe: this probe is designed for through wall installation.
Probe installation (XB32A)
Installation Note: You may want to provide an orifice at a distance of about 3” from the probe of the transmitter for future use by a reference probe and HygroPalm indicator.
•XB32A for 15mm: use parts AC1304-M (compression fitting) and AC1306 (flange) to hold and seal the probe when mounted through a wall (see Accessories).
