1 inch BSPT Connection
Threaded connection for straightforward installation in compatible liquid piping systems.
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MCDonnell & Miller
MCDonnell & Miller FS4-3J Flow Switch 1 NPT 15A 125/250VAC
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$344.50
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PRODUCT DOCUMENTATION
Product Information
Technical specifications, features, applications and purchasing information.
Technical Specifications
| Brand | MCDonnell & Miller |
| Model Number | FS4-3J |
| Product Category | Flow Switch |
| Connection Size | 1 inch BSPT |
| Switch Type | SPDT (Single-Pole Double-Throw) |
| Maximum Working Pressure | 160 PSI |
| Maximum Temperature | 300°F (149°C) |
| Minimum Temperature | 32°F (0°C) |
| Paddle Material | Stainless Steel |
| Included Paddle Sizes | 1 inch, 2 inch, 3 inch, 6 inch |
| Wetted Material | Stainless Steel |
| Fluid Type | Water, Glycol Solution |
| Maximum Flow Speed | 2 m/s |
Key Features
SPDT Switching Action
Single-pole double-throw contact configuration supports normally open and normally closed circuit control.
160 PSI Maximum Working Pressure
Rated for up to 160 PSI maximum working pressure in hydronic and process water applications.
Four Stainless Steel Paddles
Includes interchangeable 1 inch, 2 inch, 3 inch, and 6 inch stainless steel paddles for multiple pipe sizes.
Sealed Monel Bellows
Sealed Monel bellows construction supports reliable operation in compatible liquid flow detection.
Applications
- Hydronic heating systems
- Hydronic cooling systems
- Boiler pump protection
- Chiller pump protection
- Cooling tower water circuits
- Industrial process water systems
- Flow-proving circuits
- Pump interlock applications
Purchase Information
We support online purchase of the MCDonnell & Miller FS4-3J Flow Switch. If you need to make bulk purchases and inquire about other products, please contact our team to inform us of your purchase requirements. We will provide you with information such as quantity quotations, delivery dates, and transportation methods.
Frequently Asked Questions
What is the McDonnell & Miller FS4-3J? The FS4-3J is a general-purpose liquid flow switch with a 1 inch BSPT connection and SPDT switching action.
What is the maximum working pressure? The maximum working pressure is 160 PSI.
What is the temperature range? The fluid temperature range is 32°F to 300°F (0°C to 149°C).
What switch type does it use? It uses a single-pole double-throw (SPDT) snap switch.
What paddles are included? Four stainless steel paddles are included: 1 inch, 2 inch, 3 inch, and 6 inch.
What fluids is it suitable for? It is suitable for water, glycol solutions, and other compatible liquids.
What is the connection size? The connection is 1 inch BSPT.
Can it be used for pump protection? Yes, it is commonly used for boiler pump protection and chiller pump protection in hydronic systems.
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