Overview

Engineered for durability and reliability, this solid brass inline water flow switch is purpose-built for water flow detection and equipment protection in plumbing, heating, and fluid control systems. The robust all-brass construction — reinforced with stainless steel mounting screws — makes it an ideal upgrade over plastic-bodied switches in applications where pressure, temperature, or media demands a tougher build.

With its G1/2″ male inlet and G3/8″ male outlet, this flow switch is designed for easy inline installation and integrates seamlessly into existing pipework. Rated IP65 for dust and water resistance, it performs reliably in wet, outdoor, or semi-industrial environments where moisture exposure is a concern.

How It Works

This flow switch uses an internal magnetic reed switching mechanism to detect the presence or absence of water flow:

• When water flows through the body at or above the trigger flow rate, the internal mechanism is displaced, activating the reed switch and outputting an “ON” signal to the connected control system — allowing pumps, heaters, solenoid valves, or other equipment to operate.
• When water flow stops, the reed switch returns to its default state and outputs an “OFF” signal, shutting down connected equipment and protecting against dry-run or no-flow damage.

The result is a fast, clean, and repeatable digital switching action that integrates directly with PLCs, relay boards, microcontrollers, or any standard control system.

Key Features

• Full brass body construction – Superior strength, pressure resistance, and corrosion resistance vs. PP or plastic switches
• Stainless steel securing screws – Added structural integrity and resistance to rust and loosening over time
• G1/2″ male inlet × G3/8″ male outlet – Dual-size threaded ports for flexible installation in mixed-size pipework
• IP65 protection rating – Fully dust-tight and protected against water jets; suitable for outdoor and wet environments
• Reed switch technology – Reliable, low-maintenance flow detection with no moving electrical parts in the flow path
• 0.5A overload current rating – Safe, signal-level switching for integration with relay or control board circuits
• Compact, robust form factor – Dense brass block design resists vibration and mechanical stress in high-pressure lines

Specifications

Applications

• Electric water heaters (instantaneous & storage type)
• Boiler and heating system flow protection
• Pump dry-run prevention systems
• Solar water heating controllers
• Industrial process flow monitoring
• Water purification and RO filtration systems
• Cooling water circulation control
• Hydraulic and pressure system monitoring

Why Choose Brass?

Keep your water systems running safely and efficiently with this G3/8″ PP inline water flow switch. Designed to detect the presence or absence of fluid flow inside a pipeline, this compact reed-type flow switch sends a real-time digital switching signal to your control system — protecting equipment from dry-running, overheating, or operating without water. Built from durable polypropylene (PP) with an IP65-rated sealed body, it’s suitable for a wide range of residential, commercial, and light industrial fluid control applications.

How It Works

This flow switch is normally open (NO) by default:

• When water flows through the pipeline, the internal mechanism is activated by the flow, closing the reed switch and outputting an “ON” signal to the connected control system — enabling pumps, heaters, or other connected equipment to operate.
• When water stops flowing, the reed switch returns to its open state and outputs an “OFF” signal, halting system operation and protecting connected equipment from running dry.

This simple, mechanically driven mechanism requires no external power for flow sensing, making it highly reliable and low-maintenance over its rated 1,000,000-cycle lifespan.

⚠ Note: This switch is designed for low-power signal control only and is not suitable for directly switching high-power loads (e.g., 220V high-current devices). Custom 220V-rated versions are available — please contact us for details.

Key Features

• G3/8″ threaded connection – Standard sizing for easy integration into existing plumbing and tubing systems
• Normally Open (NO) by default – Activates on flow, deactivates on no-flow; Normally Closed (NC) version available on request
• IP65 protection rating – Dust-tight and splash-resistant for use in wet or humid environments
• 1,000,000-cycle mechanical & electrical life – Long-lasting, maintenance-free performance
• 0.5-second response time – Fast switching for responsive, real-time flow control
• PP shell and probe – Lightweight, corrosion-resistant construction suitable for water and mild fluid applications
• 24AWG cable with insulating tape wiring – Clean, easy-to-connect wiring for control panel integration
• Customizable options – NC type, cable length, cable material, and 220V-rated versions available upon request

Specifications

Customization Options

Applications

• Electric water heaters (instantaneous & storage type)
• Water dispensers and purification systems
• Pump dry-run protection
• Cooling water circulation monitoring
• Coffee machines and beverage equipment
• Irrigation and garden watering systems
• Industrial fluid flow detection and control
• RO (reverse osmosis) filtration systems

Important Notes

• This switch cannot directly control high-power 220V appliances. It is intended for use as a signal-level switch feeding into a control board or relay circuit.
• For high-power or 220V applications, please contact us for a customized solution.
• Normally Closed (NC) versions are available upon request.

Upgrade your fluid control system with this premium 304 stainless steel inline water flow switch, designed for reliable, long-life flow detection in demanding industrial and commercial environments. Unlike plastic-bodied alternatives, this flow switch features a full 304 stainless steel shell and probe, offering exceptional resistance to corrosion, high pressure, and harsh media. Whether you’re protecting pumps from dry-running, controlling heating systems, or monitoring process lines, this switch delivers fast, accurate, and repeatable switching performance.

How It Works

This flow switch uses a spring-loaded magnetic core displacement principle to detect flow without requiring external power for sensing:

• When fluid in the pipeline reaches or exceeds 0.75 L/min, the flowing water displaces the internal magnetic core against the reset spring. This movement causes the magnetic source to generate a magnetic control effect, triggering the sensor to output a “1” (ON) switching signal. This signal is sent to the equipment’s control system where, after power amplification, it activates the desired control function — such as starting a pump, enabling a heater, or triggering an alarm.
• When the flow rate drops below 0.75 L/min, the reset spring pushes the magnetic core back to its original resting position. The magnetic source returns to its default state, causing the sensor to output a “0” (OFF) switching signal, which halts the system’s operation and provides protection against low-flow or no-flow conditions.

This automatic, mechanically driven mechanism ensures consistent, reliable protection with no need for manual intervention or recalibration under normal operating conditions.

Key Features

• Full 304 stainless steel construction – Shell and probe both made from 304 SS for maximum corrosion resistance and compatibility with water, mild chemicals, and industrial fluids
• IP65 protection rating – Fully dust-tight and protected against low-pressure water jets, suitable for wet or outdoor environments
• Fast 0.5-second response time – Near-instant switching for time-critical control applications
• 1,000,000-cycle mechanical life – Engineered for years of continuous, maintenance-free operation
• 0.75 L/min trigger threshold – Sensitive, low-flow detection ideal for protecting equipment from dry-run conditions
• Spring-reset mechanism – Reliable return to OFF state when flow ceases, with no residual signal risk
• Digital switch output – Clean “0” / “1” switching signal for seamless integration with PLCs, microcontrollers, and control panels
• Compact inline design – Easy drop-in installation into existing pipelines with standard threaded fittings

Specifications

Applications

• Pump dry-run protection systems
• Instantaneous and storage-type electric water heaters
• Industrial process flow monitoring
• Cooling water circulation systems
• Water purification and filtration equipment
• Hydraulic and pneumatic control systems
• Solar thermal and HVAC systems
• Chemical dosing and dispensing equipment

Why Choose Stainless Steel Over Plastic?

Ensure safe, precise water and power control in your water heating system with this high-quality G1/2″ inline water flow switch. Engineered for vertical installation, this flow switch is specifically designed for use in instantaneous (tankless) electric water heaters — controlling water flow and power activation simultaneously — as well as storage-type electric water heaters, where it manages water outlet and power shutoff functions. Its compact, all-plastic construction makes it lightweight, corrosion-resistant, and easy to install in both residential and light commercial applications.

How It Works

This flow switch operates on a magnetic displacement principle, requiring no external power source to detect flow. When water enters the switch body and the flow rate reaches or exceeds 1.0 L/min, the internal magnetic core is physically displaced by the water current. This movement causes the magnetic source to generate a control effect, triggering the switch to output an “ON” signal. This signal is fed into the equipment’s control system, which executes the appropriate control action (e.g., activating a heating element or pump).

When the flow rate drops below the set threshold (0.75–3 L/min range), the magnetic core returns to its resting position, and the switch outputs an “OFF” signal, causing the control system to perform the reverse function — safely shutting off power or stopping the pump. This automatic, flow-driven mechanism provides reliable, responsive protection against dry-fire and low-flow hazards.

Key Features

• Magnetic core sensing – Reliable, mechanical flow detection with no electrical sensing components in the water path
• G1/2″ threaded connection – Standard sizing for easy integration into existing plumbing systems
• Any installation direction – Flexible mounting for tight or unconventional installation spaces
• Wide operating temperature range – Performs reliably from -10°C to 85°C
• High pressure tolerance – Rated up to 300 PSI max working pressure
• Vibration & shock resistant – Rated for 35–500Hz vibration and 30g shock resistance
• Compact, lightweight design – PP plastic body with epoxy resin sealed sensor module
• Flow precision of ±10% – Consistent, repeatable switching performance

Specifications

Applications

• Instantaneous (tankless) electric water heaters
• Storage-type electric water heaters
• Water dispensers and purification systems
• Solar water heating controllers
• Automatic washing equipment
• Industrial fluid control systems

Technical Specifications: | Feature | Specification |
| Model | RGP-W2-PW |
| Material | High-Quality Plastic (White) |
| Thread Size | G1/4″ |
| Flow Range | 0.3 – 3.0 Liters/min |
| Voltage Range | DC 4.5V – 18V |
| Rated Voltage/Current | DC 5V / ≤10mA |
| Output Signal | High Level >4.5V / Low Level <0.5V |
| Pulse Duty Cycle | 50% |
| Operating Temp| Water ≤ 60°C |
| Pressure Resistance | ≤ 1.2 MPa |
| Insulation Resistance| > 100MΩ |

Applications:

• Water Heating Systems: Ideal for gas water heaters and electric showers.

• Smart Appliances: Used in water dispensers, coffee machines, and water boilers for volume control.

• Industrial Monitoring: Real-time flow calculation for cooling or filtration systems.

Technical Specifications:

| Feature | Specification |
| Model | W1/4-NP |
| Material | High-Quality Plastic |
| Connection Size | 1/4″ Interface |
| Rated Power | 10W |
| Rated Current | 0.5A |
| Working Temperature | -10°C to 80°C |
| Main Function | Detecting fluid flow or interruption in pipelines |

Applications:

• Water Purifiers: Perfect for RO systems and household water filtration.

• Drink Dispensers: Ideal for monitoring flow in coffee machines or water coolers.

• Laboratory Equipment: Suitable for small-scale fluid control in research setups.

Installation & Usage:

• Reliable Sensing: Uses a magnetic reed switch mechanism to provide an “On/Off” signal based on water flow.

• Protection: To ensure longevity, it is highly recommended to use this switch with a Relay or Contactor when controlling devices with higher power requirements.

Technical Specifications:
| Feature | Specification |
| Model | W6-SW-L |
| Material | High-Quality Brass |
| Operating Voltage | 200V DC / 140V AC |
| Operating Current | 0.5A (DC/AC) |
| Temperature Range | -10°C to 85°C |
| Connection Size | G1/2″ Male Thread |
| Installation | Horizontal, Series connection in pipeline |

Key Benefits & Applications:

• Versatile Applications: Ideal for use in Petrochemicals, Electric Power, Metallurgy, Food Processing, and Water Treatment industries.

• Simple Installation: Designed for easy integration into existing pipelines via horizontal series mounting.

• Durable Performance: The brass material provides excellent mechanical strength and resistance to standard water pressure.

Installation Tips:

• Directional Flow: Ensure the water flows in the direction of the arrow engraved on the brass body.

• Wiring: Comes with a pre-wired connector for quick electrical setup.

• Protection: Similar to other flow switches, it is best used with a relay when controlling high-inductive loads to prolong the sensor’s lifespan.

Technical Specifications:

| Feature | Specification |

| Material |  (Stainless Steel 304) |
| Contact Type | Normally Open (NO) |
| Switching Power | 10W (Max) |
| Switching Voltage | 3V – 200V |
| Switching Current | 0.5A |
| Temperature Range | 0°C to 120°C |
| Starting Flow Rate | 5 Liters/min |
| Interface Size | G1/2″ BSP Female Thread |
| Installation | Horizontal Mount |

Why Choose This SS304 Flow Switch?

• Food & Water Safe: Stainless Steel 304 is the industry standard for water processing, ensuring safety and preventing rust contamination.

• Heat Resilient: Engineered to withstand hot water applications up to 120°C.

• Versatile Control: Compatible with a wide range of voltages (up to 200V), making it easy to integrate into PLC or relay circuits.

Professional Advice:

• Protection: Always use a Relay or Contactor if you are connecting this switch to high-power devices like pumps to prevent damaging the internal reed sensor.

• Maintenance: For the best longevity, install a Y-Strainer before the switch to keep the flow path clear of debris.

Operating Temperature: -10~100℃

• Set Range: 1…150 cm/s (Water), 3…300 cm/s (Oil), 20…2000 cm/s (Air)
• Signal Output: PNP, NPN, Relay (SPDT with Normally Open & Normally Closed)
• Power Supply: 24V ± 20% DC
• Contact Capacity: Max 400 mA (PNP or NPN type), Max 1A 48VAC/DC (Relay type), 4A 24VDC (Relay type)
• No-load Current: Max 80 mA
• Flow Indicator: LED (6 units)
• Set Method: Electric position setting
• Pressure Range: 100 bar
• Medium Temperature Change Rate: ≤4°C/s
• Response Time: 1…13 s, typical value 2 s
• Initialization Time: Approximately 8 s
• Electrical Protection: Reverse polarity, short circuit, overload protection
• Protection Level: IP67
• Medium Temperature: -20…90°C (High-temperature version available: -40…150°C)
• Ambient Temperature: -20…80°C
• Storage Temperature: -20…100°C
• Connection Method: M12 connector
• Material: Probe: Stainless Steel (304/316 optional), Housing: POM (Engineering Plastic)
• Repeatability: ±2%