Vaisala HMP4 - Figure 29 HMP3 Probe Head with Filter Removed

Only the HUMICAPâ R2 sensor is designed to be replaced by the
user. Other humidity sensor types available for HMP series probes are composite
sensors where the humidity sensor and temperature sensor are permanently
attached together. If you need to replace a composite sensor, contact a Vaisala
Service Center.
CAUTION!
Sensors are easily damaged when the filter is not in place. Handle
the probe head carefully.
CAUTION!
Reverting the probe to factory settings clears the adjustment values
entered in this procedure. If you need to revert the probe to factory settings
after replacing the sensor yourself, write down the values on the Adjustment
data page beforehand, and enter them again after applying the factory settings.
CAUTION!
2
1
Figure 29 HMP3 probe head with filter removed
1
Pt100 temperature sensor
2 HUMICAPâ R2 humidity sensor
1. Put on clean gloves before touching the filter.
2. Turn the filter counter-clockwise to loosen it.
3. Remove the filter from the probe head. Be careful not to touch the sensors with the filter.
4. There are two sensors under the filter, the HUMICAPâ sensor and a temperature sensor.
Identify the HUMICAPâ sensor and make sure it is of the R2 type (temperature sensor not
attached to it).
Chapter 7 – Maintenance
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