The Setra SRH Duct Mount humidity transmitter is built to sit directly in an air duct, measuring relative humidity and temperature in the moving airstream rather than at a wall or room location. It uses a durable capacitive sensor rated for 0-99% full-scale RH measurement, and it recovers cleanly even after being saturated at 100% RH, which matters in duct runs where condensation can happen after a cooling coil or during startup.
In actual application, this unit can be ordered with either an active (analog) temperature output or a passive RTD/thermistor output, so you get two measurements – humidity and temperature – from one device. The humidity accuracy comes in 2%, 3%, or 5% RH options depending on how tight you need the reading, and the analog output can be 4-20mA or user-selectable 0-5Vdc/0-10Vdc. The housing is a polycarbonate UL94V-0, NEMA4 enclosure, so it holds up well in mechanical rooms and duct environments.
From our experience, one of the more practical features here is the replaceable sensor tip. If the sensor drifts or gets contaminated after a while in the duct, you just swap the tip – no special training needed, and no field calibration required since each replacement tip is factory calibrated before it ships. That’s a real time saver on maintenance rounds. It also comes with a 5-year warranty on the electronics and a 2-year warranty on the sensor module.
Before we quote this, we would normally check the accuracy class you need, whether you want active or passive temperature output, and the analog output type your BMS expects. Hope this helps.
