The Hotowell HTW-WS series is a paddle-type (vane) flow switch designed for reliable flow monitoring in water and non-hazardous liquid systems. It is commonly used in HVAC applications, chillers, pumps, and industrial water circuits where accurate flow/no-flow detection is required for equipment protection and system control.

Working Principle

The HTW-WS operates on a simple mechanical vane principle. When liquid flows through the pipe at a sufficient rate, the paddle (vane) is displaced by the fluid force. This movement actuates an internal SPDT microswitch, which changes its contact state to signal flow presence. When flow drops below the set point, the paddle returns to its resting position, and the switch resets. The set point is adjustable via a screw on the device.

Key Features

• SPDT Output: Provides a single-pole, double-throw contact rated at 15A @ 220 VAC, capable of directly controlling pumps, valves, or alarms.
• Wide Pressure and Temperature Range: Maximum static pressure rating of 10 bar (1 MPa) and maximum liquid temperature of 100°C, suitable for demanding industrial and HVAC applications.
• IP54 Protection: The plastic housing with 1/2" conduit opening provides protection against dust and splashing water.
• Flexible Installation: Can be installed in horizontal or vertical pipelines (flow upward for vertical installation). Requires 5 pipe diameters of straight run on each side.
• Field Adjustable: The flow set point can be adjusted on-site using the adjustment screw (clockwise for higher flow, counterclockwise for lower flow).
• Screw Terminal Connection: Easy wiring with screw terminals inside the housing.

Technical Specifications

• Media Compatibility: Water and non-hazardous liquids not harmful to brass or phosphor bronze.
• Thread Diameter: Approx. 1.30 inches (33 mm)
• Pipe Diameter Compatibility: Approx. 0.86 inches (22 mm)
• Certifications: CE marked
• Housing Material: Plastic cover with 1/2" conduit opening

Applications

The HTW-WS series is ideal for flow/no-flow detection and pump protection in HVAC systems, chillers, cooling towers, water treatment, and general industrial water circuits.