Paddle Flow Switch

What Is a Paddle Flow Switch?

A paddle flow switch is a mechanical device used to detect liquid flow in a pipeline. As liquid moves through the pipe, it deflects a paddle and actuates an electrical contact when the flow reaches the switching point. These switches are commonly used for pump protection, HVAC systems, chillers, cooling water circulation, and industrial liquid flow monitoring.

ZINACA offers target, baffle, and other paddle flow switch models for different industrial applications. Explore the products below to compare available options. Selection should consider the liquid medium, pipe size, operating pressure, temperature, and required flow switching point.

How to Choose a Paddle Flow Switch

A paddle flow switch detects whether liquid flow in a pipeline has reached a switching point. It provides an on/off signal for alarms, equipment interlocks or pump protection. Unlike a flow meter, a standard paddle flow switch does not provide continuous flow-rate measurement.

ZINACA supplies mechanical paddle flow switches for applications including HVAC circulation, water treatment, cooling circuits and industrial equipment. Selection depends on the medium, pipe size, flow setpoint, process conditions and required electrical contact.

Compare Paddle Flow Switch Models

• Target Paddle Flow Switch (ZNC-LSFS-T): a vane-type mechanical switch for water circulation, HVAC, chillers and general liquid flow detection. The product page lists SPDT switching and an adjustable flow setpoint.

• Baffle Paddle Flow Switch (ZNC-LSFS-B): a compact mechanical design with a built-in microswitch. Check the specified flow range, pressure rating and installation connection for your selected configuration.

• ZNC-PFS Paddle Liquid Flow Switch: an adjustable SPDT model with brass or stainless steel body options, IP65 protection and 1/2", 3/4" or 1" NPT process connections, depending on the model.

For hazardous-area applications, please request the exact model documentation and confirm the applicable explosion-protection approvals before specifying a product.

Typical Industrial Applications

• HVAC and chillers: confirm water circulation before enabling or continuing equipment operation.

• Pump protection: send a flow-loss alarm or interlock signal when the switching threshold is not met.

• Cooling water systems: detect insufficient flow to heat exchangers or process equipment.

• Water treatment: monitor the presence of flow in compatible liquid lines.

What Information Is Needed for Selection?

To select a suitable paddle flow switch, please provide:

• Liquid medium and wetted-material compatibility requirements

• Pipe size and process connection type

• Normal flow rate and required switching point

• Operating pressure and liquid temperature

• Switch contact requirements, such as SPDT, NO or NC

• Installation orientation and any hazardous-area requirements, if applicable

The paddle size and flow adjustment range must match the pipeline conditions. Confirm the actual switching range using the selected model's technical datasheet.

How Does a Paddle Flow Switch Work?

Flowing liquid deflects a paddle inserted into the pipeline. This movement actuates a mechanical switching element when the flow reaches its setpoint. When flow decreases, the paddle returns and the switch changes state according to its design. Read our guide to paddle flow switch working principles for a detailed explanation.

Paddle or Thermal Flow Switch?

Paddle switches use a moving element and are often selected for straightforward water-flow interlocks. Thermal flow switches use a heat-transfer sensing principle and may be preferable where a different switching range, fluid condition or installation method is required. Model selection should be based on actual process data rather than the sensing principle alone.

Request a Paddle Flow Switch Quotation

Send ZINACA your medium, pipe size, flow setpoint, pressure, temperature, connection and contact requirements. We can review available models and prepare a quotation for the required configuration.

Contact ZINACA Instruments or email sales@zinacainstruments.com.