Water flow sensor YS300A G3/4“ DN20 DC5~15V

Description

The YS300A (FS300A) is a Hall-effect turbine water flow sensor designed for inline measurement of liquid flow rate and total volume in plumbing, irrigation, water heaters, and industrial control applications. It features a G3/4″ (DN20) threaded connection and is intended for medium-to-high flow water lines where the smaller 1/2″ sensors cannot accommodate the required flow rate.

The sensor consists of a plastic body containing a magnetic pinwheel rotor and a Hall-effect sensor sealed from the water path. As water flows through, the rotor spins at a rate proportional to flow velocity, and the Hall sensor outputs a digital pulse train. The pulse frequency is proportional to flow rate, allowing the microcontroller to calculate instantaneous flow (L/min) and cumulative volume (liters). The FS300A G3/4″ variant is rated for a flow range of 2–60 L/min, with a pulse characteristic of 390 pulses per liter and a frequency relationship of F = 6.5 × Q (Hz, where Q is L/min) according to one detailed supplier table .

The sensor operates from DC 3.5V to 24V (5V typical) with a maximum current draw of 15mA and outputs an NPN pulse signal . Accuracy is typically listed at ±10%, making it suitable for relative monitoring and control rather than precision metering. The maximum water pressure is ≤2.0 MPa, and the maximum liquid temperature is ≤120°C .

Critical limitations: This is a low-cost, non-certified sensor intended for educational, hobbyist, and light commercial use. The pulse rate varies with flow rate, pressure, and orientation, and calibration against a known volume is recommended for better precision. For 3.3V microcontrollers (ESP32, ESP8266), the 5V pulse output requires a logic level shifter or voltage divider to protect the GPIO pins.

Features

• G3/4″ (DN20) Threaded Connection: Standard pipe size for medium-to-high flow water lines in plumbing and irrigation .

• Hall-Effect Pulse Output: Digital square wave proportional to flow rate, readable by any microcontroller with an interrupt-capable GPIO.

• Wide Flow Range (2–60 L/min): Suitable for water heaters, irrigation systems, and industrial flow monitoring .

• 390 Pulses per Liter (nominal): Provides good resolution for volume tracking .

• Wide Voltage Range (DC 3.5–24V): 5V typical for Arduino; flexible for different power supplies .

• Low Power Consumption: Maximum 15mA at 5V .

• Sealed Hall Sensor: The sensing electronics are isolated from the water path.

• High Pressure and Temperature Tolerance: Max pressure ≤2.0 MPa; liquid temperature ≤120°C .

Technical Specifications