Saier HZ21WC Water Flow Sensor (1–30 L/min, 4.5–18V DC)

The HZ21WC provides flexible output options. It can generate a digital pulse signal (frequency proportional to flow rate) for direct counting by a microcontroller, as well as an analog voltage output. The high-level output is ≥4.5V when powered at VDD, and the low level is ≤0.5V, making it compatible with both 5V and 3.3V logic systems with appropriate signal conditioning.

Yes, the sensor's durable turbine mechanism and construction make it suitable for monitoring compatible dry gases, such as compressed air or inert gases, in addition to water and other non-corrosive liquids. Ensure the gas is clean, dry, and within the specified pressure limit (≤1.75 MPa) to prevent damage to the internal bearings and ensure accurate readings.

Connect the red wire to a DC power source between 4.5V and 18V. Connect the black wire to ground. The yellow (or signal) wire provides the output. For digital mode, connect it to a microcontroller's digital input pin. For analog mode, connect it to an ADC input. Always include a pull-up resistor if required by your controller for a clean digital signal. The sensor draws less than 15mA during operation.

The sensor has a stated accuracy of 5–8% across its 1–30 L/min range. For precise measurement, calibration against a known flow standard is recommended. You can establish a calibration curve by measuring the output pulse frequency or analog voltage at several known flow rates and applying a linear or polynomial correction factor in your controller's firmware or software.

The sensor is rated for a maximum working pressure of 1.75 MPa (approximately 250 psi). It is designed for water and compatible fluids at typical ambient temperatures. For continuous high-temperature (e.g., >60°C) or high-pressure applications beyond its rating, a dedicated industrial-grade flow transmitter with appropriate material certifications should be used to ensure safety and longevity.