Hall water flow sensor DN20 G3/4 Copper flow meter YF-B9 DC3.5~24V [4 points inner teeth inlet 4 points inner teeth outlet G1/2]

$5.45

SKU: FA3105-9 Category:

Description

The YF-B9 is a Hall-effect turbine water flow sensor featuring a copper/brass housing with a G3/4″ (DN20) threaded connection. It is designed for medium-to-high flow measurement in water quality monitoring, hydroponics, aquariums, industrial water treatment, and smart irrigation systems .

The sensor operates on a turbine principle: water flowing through the body spins a magnetic rotor, and an integrated Hall-effect sensor detects the rotation, outputting a digital pulse train proportional to flow rate . The rated flow range is 2–50 L/min, with a maximum water pressure of 1.75 MPa .

The sensor operates from DC 3.5–24V (per Russian supplier and Alibaba listing) or DC 5–15V (per Zbotic and Iranian supplier) , with a maximum current draw of approximately 15mA. The output is an NPN pulse signal with high level >4.7V at 5V input .

Critical limitations: This is a low-cost, non-certified sensor for hobbyist, educational, and light commercial use. For 3.3V microcontrollers (ESP32, ESP8266), the pulse output high level (>4.7V at 5V supply) requires a logic level shifter or voltage divider to protect GPIO pins. Note that one supplier explicitly states the YF-B9 is “suitable for cold water only” and not rated for sustained hot water temperatures , which conflicts with another source listing liquid temperature up to 120°C . Verify your unit’s temperature rating with your supplier.

Features

  • Copper/Brass Housing: Corrosion-resistant and durable; suitable for water monitoring and industrial applications .

  • Hall-Effect Pulse Output: Digital square wave proportional to flow rate; pulse factor varies by source (verify with supplier).

  • Flow Range 2–50 L/min: Suitable for medium-to-high flow applications including branch lines and irrigation .

  • G3/4″ (DN20) Threaded Connection: Standard ¾-inch pipe size for easy integration .

  • Wide Voltage Range (DC 3.5–24V per some sources): Flexible compatibility with different supply systems .

  • High Pressure Resistance (≤1.75 MPa): Suitable for pressurized water systems .

  • Sealed Hall Sensor: Electronics isolated from the water path for durability .

  • Compact Brass Body: Durable threads for better sealing with standard plumber’s tape .

Technical Specifications

Parameter Specification
Model YF-B9
Connection Size G3/4″ (DN20)
Thread Configuration Verify with supplier (not clearly documented as female/female)
Body Material Copper/Brass
Operating Voltage DC 3.5–24V or DC 5–15V
Max Current Draw ~15mA
Output Signal NPN pulse; high >4.7V, low <0.5V (at 5V input)
Flow Rate Range 2–50 L/min
Pulse Formula Varies: (8.1Q-3) , 8Q-4 , or 476 pulses/L
Max Water Pressure ≤1.75 MPa
Operating Temperature ≤80°C (per one source)
Liquid Temperature ≤120°C (per one source) ; “cold water only” (per another) 

Additional information

Model

YF-B9

Connection Size

G3/4" (DN20)

Thread Configuration

Verify with supplier (not clearly documented as female/female)

Body Material

Copper/Brass

Operating Voltage

DC 3.5–24V or DC 5–15V

Max Current Draw

~15mA

Output Signal

NPN pulse; high >4.7V, low <0.5V (at 5V input)

Flow Rate Range

2–50 L/min

Pulse Formula

Varies: (8.1Q-3) , 8Q-4 , or 476 pulses/L

Max Water Pressure

≤1.75 MPa

Operating Temperature

≤80°C (per one source)

Liquid Temperature

≤120°C (per one source) ; "cold water only" (per another)

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