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    Picture of 3/8" Digital Water Flow Switch, NPN/ PNP/ 4-20mA/1~5V Picture of 3/8" Digital Water Flow Switch, NPN/ PNP/ 4-20mA/1~5V Picture of 3/8" Digital Water Flow Switch, NPN/ PNP/ 4-20mA/1~5V Picture of 3/8" Digital Water Flow Switch, NPN/ PNP/ 4-20mA/1~5V

    3/8" Digital Water Flow Switch, NPN/ PNP/ 4-20mA/1~5V

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    SKU: SUCH-FLS-NPF3W70403
    $306.39
    ● 3/8 inch connection diameter ● 0.5-4 L/min rated flow range ● NPN/ PNP/ 4-20mA/1~5V ● Water, ethylene glycol aqueous solution
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    🕒 Delivery date: 6-12 days
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    Overview

    High-precision 3/8-inch digital water flow switch for industrial water systems and cooling circulation systems. The water flow switch supports precise measurement and display of 0.35–5.50 L/min, with a minimum setting increment of 0.01 L/min. It features dual display of instantaneous and cumulative flow, with a maximum cumulative reading of 99999999.9 L. Constructed from corrosion-resistant materials (PPS/SUS304), it is suitable for operating conditions ranging from 0–90°C and ensures stable operation in complex environments. The flow switch features built-in upper and lower limit alarms and hysteresis modes, making it widely applicable for equipment protection, flow monitoring, and automatic control systems.

    Feature

    3-8 inch digital air flow switch feature

    • The digital water flow switch employs the Karman vortex street detection principle to reliably monitor flow rates from 0.5 to 4 L/min, making it suitable for precision flow control applications.
    • Equipped with a dual-sided 4-digit, 7-segment dual-color LED display, it simultaneously shows instantaneous and cumulative flow rates, enabling real-time monitoring of system operation.
    • The 3/8 inch digital water flow switch supports NPN or PNP outputs, along with 1–5V and 4–20mA analog signal outputs, enabling seamless integration with PLCs, controllers, or automation systems.
    • Operating within 0–1MPa pressure and 0–90°C medium temperatures, the switch is constructed from corrosion-resistant materials including PPS, SUS304, and FKM, ensuring long-term stable performance.

    Dimension (unit: mm)

    Body Dimension

    Digital water flow switch dimension

    Basic Dimensions A AA B D E F G H
    70 50 30 60 40.6 15.2 24 14
    J K L N P / / /
    35 26 18 13.6 Ø2.7 deep 14 / / /
    Bracket Dimensions S T U V W WX Y Z
    24 22 32 40 50 4.5 5 1.5


    M8 Lead Wire Dimension

    Digital water flow switch lead wire dimension

    Detail

    Digital water flow switch details

    1. Function Panel: Enables switching between functions and rapid application response.
    2. Water Sensor: Specifically designed to detect water flow and transmit data to the main board.
    3. Main Board: Stores memory data, records data, and provides real-time display.

    Pin Number & Wire Color

    Digital water flow switch wire color

    Pin Number Content Wire Colors
    1 DC (+) Brown
    2 OUT 2 White
    3 DC (-) Blue
    4 OUT 1 Black


    Flow Rate Diagram

    Digital water flow switch flow rate diagram

    Output Type A B C
    Voltage Output 1 V 1.5 V 5 V
    Current Output 4 mA 6 mA 20 mA
    Specs
    Connection Diameter Rc(PT) 3/8 inch
    Measured Fluid Water and ethylene glycol water solutions (viscosity ≤3 mPa·s / 3 cP)
    Detection Method Karman vortex street type
    Rated Flow Range 0.5–4 L/min
    Display Flow Range 0.35–5.50 L/min
    Set Flow Range 0.35–5.50 L/min
    Minimum Setting Unit 0.01 L/min
    Cumulative Pulse Conversion Value 0.05 L/pulse
    Operating Fluid Temperature 0–90°C (non-condensing)
    Display Unit Instantaneous flow L/min, cumulative flow L
    Accuracy Display value ±3% F.S., analog output ±3% F.S.
    Repeatability ±2% F.S.
    Temperature Characteristics ±5% F.S. (at 25°C reference)
    Operating Pressure Range 0–1 MPa
    Pressure Loss 45 kPa at max. flow (without flow control valve)
    Cumulative Flow Range 99999999.9 L / per 0.1 L
    Output Type NPN or PNP open-collector output
    Voltage Output 1–5 V (output impedance 1 kΩ)
    Current Output 4–20 mA
    Maximum Load Current 80 mA
    Maximum Applied Voltage DC 28 V
    Internal Voltage Drop NPN: ≤1 V (80 mA load) / PNP: ≤1.5 V (80mA load)
    Response Time 0.5s / 1s / 2s
    Output Protection Short-circuit protection
    Output Mode Hysteresis mode, upper/lower limit comparison mode, cumulative output mode, cumulative pulse output mode
    Load Impedance DC12V: 300Ω
    DC24V: 600Ω
    Hysteresis Adjustable
    External Input No voltage input: ≤0.4V (with or without contact), input ≥30ms
    Display Method Dual-sided display
    Display Screen 4-digit 7-segment 2-color LED
    Operation Indicator Output 1 / Output 2: Orange
    Power Supply Voltage DC12–24V ±10%
    Current Consumption ≤50mA
    Protection Rating IP65
    Operating Temperature Range 0–50°C (non-condensing)
    Operating Humidity Range 35–85%RH (non-condensing)
    Withstand Voltage AC1000V 1 minute
    Insulation Resistance ≥50MΩ (DC500V)
    Wetted Parts Material PPS / SUS304 / FKM / SCS13
    Standards and Regulations CE, UL(CSA), RoHS
    Lubrication Grease-free specification
    Weight 1kg
    Application

    Central air conditioning system

    Central Air Conditioning System

    Digital water flow switch for boiler equipment

    Boiler Equipment

    Water purification equipment

    Water Purification Equipment

    FAQ
    ❯

    A digital water flow switch is a control device that integrates flow detection and real-time display functions, used to monitor changes in liquid flow within pipelines. When flow reaches a preset value, the switch outputs a control signal to activate functions such as equipment start-up, shutdown, or alarm triggering. Its digital display provides real-time readings of current flow rates or status information, enabling users to intuitively observe system operation.

    ❯

    Digital water flow switches typically detect water flow changes through internal flow sensing elements (such as turbines, Hall sensors, or magnetic assemblies). As liquid passes through the sensor, these internal components generate corresponding signals that are converted into electrical signals. These signals are processed by the control circuit and displayed on the digital screen. Simultaneously, the system compares this signal against a preset flow value. When the flow exceeds or falls below the threshold, it outputs a switch signal to control related equipment.

    ❯

    Digital water flow switches are suitable for various liquid flow monitoring and control scenarios, such as industrial cooling water circulation systems, central air conditioning systems, boiler equipment, water heaters, water purification equipment, and agricultural irrigation systems.

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