This manual describes the features and usage of Vaisala HUMICAP® humidity and temperature transmitters.
The HMD70U/Y series are duct‑mounted three‑wire transmitters for measuring humidity (HMD70U) and humidity plus temperature (HMD70Y). Both models use the HUMICAP®180 humidity sensor, while the HMD70Y adds a Pt 1000 temperature sensor.
The manual covers proper site selection, mounting, grounding, electrical connections, one‑point and two‑point calibration procedures (using the HMI41 indicator and calibration cable 1911622), and routine maintenance such as sensor and filter replacement.