We ship worldwide — Singapore, Australia, Malaysia, Indonesia, Philippines, India, Middle East & more

MCDONNELL & MILLER Flow Switch: 3/4 in For Pipe Size, 3/4 in NPT, 3/4 in Connection Size - Inline Switches for Liquids
McDonnell & MillerInline Switches for Liquids

MCDONNELL & MILLER Flow Switch: 3/4 in For Pipe Size, 3/4 in NPT, 3/4 in Connection Size

The MCDONNELL & MILLER Flow Switch, model FS6-3/4, is an inline switch for liquids designed for 3/4 in pipe size with a 3/4 in NPT connection. It features a SPDT contact configuration and an AC contact rating of 7.4…

SKU 3G-OTH-88487

Also listed as: FS634 · FS6 3 4 · FS6-3-4

Brand
McDonnell & Miller
Item
Flow Switch: 3/4 in For Pipe Size, 3/4 in NPT, 3/4 in Connection Size
Category
Inline Switches for Liquids
Available to Order
Trade pricing by quote — replies within 24h
Qty
WhatsApp an engineerMessage via Telegram
No account needed — your quote request goes straight to our engineers. A free account lets you track quotes and re-order faster.
Worldwide Shipping
Air & sea freight
Datasheet on Request
Technical specs
1-Day Quote
Replies within 24h

Local availability & support

Delivery
Worldwide DHL shipping from Singapore; 7–14 business days door-to-door for most destinations.
Payment
Invoicing in USD. Bank transfer (SWIFT) and corporate PO accepted.

Technical Specifications

McDonnell & Miller
Manufacturer Part Number
FS6-3/4
Type
NPT, SPDT
NPT
3/4 in
For Pipe Size
3/4 in
Connection Size
3/4 in
Contact Rating (AC)
7.4 A @ 120V (Full Load)

Technical Documents

No technical documents available for this product.
Request documentation
Not sure this is the right part? Get a recommendation.

Need installation or engineering help?

Installation, commissioning, maintenance plans, system design, and bundled product + service quotes — one team handles the full scope.
Talk to an engineer

Ask a question

McDonnell & Miller Products
3G Electric (S) Pte. Ltd. — Singapore

Product Description

The MCDONNELL & MILLER Flow Switch, model FS6-3/4, is an inline switch for liquids designed for 3/4 in pipe size with a 3/4 in NPT connection. It features a SPDT contact configuration and an AC contact rating of 7.4 A at 120V full load.

Frequently Asked Questions

What is the McDonnell & Miller FS6-3/4 flow switch used for?

The McDonnell & Miller FS6-3/4 is an inline flow switch for liquids that detects flow or no-flow conditions in 3/4 in pipe systems. It is commonly used in HVAC, boiler, and industrial process applications to interlock pumps, alarms, or burners when flow is lost.

What are the specifications of the McDonnell & Miller FS6-3/4 flow switch?

The FS6-3/4 has a 3/4 in NPT connection, SPDT contact configuration, and an AC contact rating of 7.4 A at 120 V full load. It is designed for 3/4 in pipe size and is manufactured by McDonnell & Miller under part number FS6-3/4.

Where to buy the McDonnell & Miller FS6-3/4 flow switch worldwide?

3G Electric supplies the McDonnell & Miller FS6-3/4 flow switch to customers worldwide. We handle full logistics, customs clearance, and delivery to your site. Contact us for a quote and lead time on this model.

How to install the McDonnell & Miller FS6-3/4 flow switch?

Install the FS6-3/4 in a horizontal pipe run with the flow arrow aligned to flow direction. Use thread sealant on the 3/4 in NPT connection and wire the SPDT contacts per your control circuit. Always follow local codes and the manufacturer's manual for safe operation.

Used in

Common applications for McDonnell & Miller
Steam boiler low-water cutoff — McDonnell & Miller inline flow switches (e.g., FS-1) for automatic burner shutdown
Cooling water flow monitoring — McDonnell & Miller insertion-style switches (e.g., FS4-3D) in large-diameter pipes
Hazardous-area process lines — McDonnell & Miller FS7-4E with NEMA 7/9 enclosure for Class I, Div 1 locations
HVAC chilled water systems — McDonnell & Miller FS6-1 inline switch for pump flow verification
Industrial wastewater treatment — McDonnell & Miller FS4-3S stainless steel switch for corrosive fluid flow detection
Boiler feedwater control — McDonnell & Miller FS8-WJ with BSP connections for international installations

McDonnell & Miller Products

3G Electric supplies McDonnell & Miller inline switches for liquids. We supply genuine products with in-stock availability on common SKUs, technical documentation, commissioning support, and warranty service — worldwide.

You might also need

Burners & Combustion Pumps & Compressors Spare Parts All Products

Compatible alternatives & equivalents

Cross-referenced by specification & description
Siemens
Siemens
Magnetic Valve: 14 Cv Flow Rate, 2-Way, 1 1/4 in Union NPT, Spring Return, NC, Floating Signal (MPN MXG461.32-12U)
Siemens
Siemens
Magnetic Valve: 9.4 Cv Flow Rate, 2-Way, 1 in Union NPT, Spring Return, NC, Floating Signal (MPN MXG461.25-8.0U)
Siemens
Siemens
Magnetic Valve: 5.9 Cv Flow Rate, 2-Way, 3/4 in Union NPT, Spring Return, NC, Floating Signal (MPN MXG461.20-5.0U)
Magnetic Valve: 5.9 Cv Flow Rate, 2-Way, 3/4 in Flanged, Spring Return, NC, Proportional Signal (MPN MVF461H20-5)
Siemens
Magnetic Valve: 5.9 Cv Flow Rate, 2-Way, 3/4 in Flanged, Spring Return, NC, Proportional Signal (MPN MVF461H20-5)
Siemens
Siemens
Magnetic Valve: 14 Cv Flow Rate, 2-Way, 1 1/4 in Flanged, Spring Return, NC, Proportional Signal (MPN MVF461H32-12)
TELEMECANIQUE SENSORS Water Pump Switch: Reverse, 10 psi – 45 psi, 1/4" FNPS, 10 psi / 5 psi ON/OFF (MPN 9013FRG32J23)
TELEMECANIQUE SENSORS
TELEMECANIQUE SENSORS Water Pump Switch: Reverse, 10 psi – 45 psi, 1/4" FNPS, 10 psi / 5 psi ON/OFF (MPN 9013FRG32J23)

More from McDonnell & Miller

View all McDonnell & Miller parts
MCDONNELL & MILLER Flow Switch: Paddle, 1 in For Pipe Size, 1 in NPT, 1 in Connection Size, NPT (MPN FS8-W)
McDonnell & Miller
MCDONNELL & MILLER Flow Switch: Paddle, 1 in For Pipe Size, 1 in NPT, 1 in Connection Size, NPT (MPN FS8-W)
MCDONNELL & MILLER Flow Switch: Paddle, 1 in For Pipe Size, 1 in NPT, 1 in Connection Size, NPT (MPN FS4-3T3-1)
McDonnell & Miller
MCDONNELL & MILLER Flow Switch: Paddle, 1 in For Pipe Size, 1 in NPT, 1 in Connection Size, NPT (MPN FS4-3T3-1)
MCDONNELL & MILLER Flow Switch: Paddle, 1 in For Pipe Size, 1 in BSP, 1 in Connection Size, BSP (MPN FS8-WJ)
McDonnell & Miller
MCDONNELL & MILLER Flow Switch: Paddle, 1 in For Pipe Size, 1 in BSP, 1 in Connection Size, BSP (MPN FS8-WJ)
MCDONNELL & MILLER Flow Switch: 1/2 in For Pipe Size, 1/2 in NPT, 1/2 in Connection Size, NPT, SPDT (MPN FS-1)
McDonnell & Miller
MCDONNELL & MILLER Flow Switch: 1/2 in For Pipe Size, 1/2 in NPT, 1/2 in Connection Size, NPT, SPDT (MPN FS-1)
MCDONNELL & MILLER Flow Switch: 1 in For Pipe Size, 1 in NPT, 1 in Connection Size, NPT, SPDT (MPN FS6-1)
McDonnell & Miller
MCDONNELL & MILLER Flow Switch: 1 in For Pipe Size, 1 in NPT, 1 in Connection Size, NPT, SPDT (MPN FS6-1)
MCDONNELL & MILLER Flow Switch: 1 in For Pipe Size, Brass, 1 in NPT, 1 in Connection Size, NPT, SPDT (MPN FS5-1)
McDonnell & Miller
MCDONNELL & MILLER Flow Switch: 1 in For Pipe Size, Brass, 1 in NPT, 1 in Connection Size, NPT, SPDT (MPN FS5-1)
MCDONNELL & MILLER Liquid Flow Switch: 3/4 in For Pipe Size, Brass, 3/4 in NPT, NPT, 32°F to 250°F (MPN FS5-3/4)
McDonnell & Miller
MCDONNELL & MILLER Liquid Flow Switch: 3/4 in For Pipe Size, Brass, 3/4 in NPT, NPT, 32°F to 250°F (MPN FS5-3/4)
MCDONNELL & MILLER Flow Switch: 3/4 in For Pipe Size, 3/4 in NPT, 3/4 in Connection Size, NPT, SPDT (MPN FS6-W-3/4)
McDonnell & Miller
MCDONNELL & MILLER Flow Switch: 3/4 in For Pipe Size, 3/4 in NPT, 3/4 in Connection Size, NPT, SPDT (MPN FS6-W-3/4)