Honeywell

Honeywell FS4-3S Liquid Flow Switch

SKU FS4-3S/U

In stock
  • 12-month warranty
  • Free returns within 30 days

  • Manufacturer: Honeywell

  • Product No.: FS4-3S/U

  • Country of origin:United States

  • Product Type: Flow Switches

  • Payment: T/T, Western Union

  • Weight: 900g

  • Shipping port: Xiamen

  • Warranty: 12 months

Description

Industrial fluid process monitoring requires resilient hardware, and the FS4-3S flow switch provides exceptional performance in challenging environments. This liquid flow sensor utilizes a paddle actuation mechanism to monitor fluid movement in closed piping systems. Featuring a high-durability stainless steel body and Monel bellows, the FS4-3S (Part Number 114641 / FS4-3S/U) is engineered to withstand corrosive process fluids where standard brass components would degrade.

The mechanical action of fluid flow against the paddle triggers a Single-Pole Double-Throw (SPDT) electrical switch. This simple yet highly reliable design allows operators to integrate the flow switch into automated control networks to cycle pumps, activate alarms, or signal downstream PLC or DCS platforms during critical flow fluctuations.

Features

  • Corrosion-Resistant Construction: Built with a stainless steel body and Monel bellows to handle aggressive or brackish liquids safely.
  • Flexible Switching: SPDT electrical contact structure supports both normally open and normally closed wiring profiles.
  • Mechanical Actuation: Responds accurately to fluid velocity variations to provide immediate system protection.
  • Industrial Durability: Designed for heavy-duty industrial processing environments requiring stable physical sealing.

Applications

  • Industrial chemical processing lines.
  • Water treatment and hydronic filtration systems.
  • HVAC liquid cooling loop monitoring.
  • Boiler feed water line supervision.

Technical Specifications

Manufacturer Honeywell
Part Number / Model FS4-3S (114641 / FS4-3S/U)
Body Material Stainless Steel
Bellows Material Monel
Switch Contact Configuration SPDT (Single Pole Double Throw)
Weight 0.9 kg

Connections and Interfaces

Terminal Designation Function
Common (C) Line input connection
Normally Closed (NC) Opens contact on liquid flow increase
Normally Open (NO) Closes contact on liquid flow increase

Installation Guidelines

  • Orientation: Mount exclusively in horizontal pipe runs where the paddle assembly hangs vertically downward.
  • Upstream/Downstream Clearances: Provide a minimum of five pipe diameters of straight, unobstructed piping upstream and downstream of the switch.
  • Flow Direction: Ensure the arrow cast on the switch housing aligns with the actual fluid flow direction inside the pipe.
  • Electrical Wiring: De-energize control loops prior to servicing or terminating wires to the SPDT screw terminals.

FAQ

What materials are used in the Honeywell FS4-3S flow switch?
The Honeywell FS4-3S features a high-grade stainless steel body and Monel bellows, providing superior corrosion resistance for aggressive fluid processes compared to standard brass switches.

What type of electrical switch does the FS4-3S utilize?
The device utilizes a Single-Pole Double-Throw (SPDT) switch contact, allowing it to control two separate electrical circuits or signal states depending on the flow conditions.

Can this switch be mounted in any orientation?
No, the FS4-3S should be mounted in a horizontal pipe run with the paddle pointing vertically downward to ensure accurate flow actuation and return.

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Global Express Shipping

  • Standard Delivery: 4–6 business days via DHL, FedEx, and UPS.
  • Express Dispatch: Same-day dispatch for in-stock orders placed before 2:00 PM (GMT+8).
  • Worldwide Coverage: Serving over 150 countries.

Returns & Warranty

  • 30-Day Guarantee: Returns accepted for in-stock products in original, factory-sealed packaging.
  • 12-Month Warranty: Every industrial component is backed by our technical warranty.
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Global Express Shipping

  • Standard Delivery: 4-6 Business Days via DHL, FedEx, and UPS.
  • Express Dispatch: Same-day dispatch for in-stock orders placed before 2:00 PM (GMT+8).
  • Worldwide Coverage: Serving over 150 countries, including rapid delivery to Saudi Arabia and UAE.

Returns & Warranty

  • 30-Day Guarantee: Returns accepted for in-stock products in original, factory-sealed packaging.
  • 12-Month Warranty: Every industrial component is backed by our professional technical warranty.

Orders are processed and delivered Monday-Friday (excluding public holidays).


For full eligibility, restocking fees, and international return details, please view our official Refund & Return Policy .

TECHNICAL SPECIFICATIONS

Country of origin
United States

Technical knowledge

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