When selecting a duct high limit switch for your HVAC system, reliability matters. These safety controls are designed to shut down heating and ventilation equipment when duct temperatures exceed a safe operating limit, helping protect both equipment and building occupants.
While many temperature controls are manufactured overseas, Firestat duct high limit switches are proudly designed, manufactured, assembled, and tested by Senasys in Eau Claire, Wisconsin. Every switch is built with quality, reliability, and long-term performance in mind.
Why Choose a Made-in-the-USA Duct Limit Switch?
For contractors, facility managers, OEMs, and distributors, purchasing American-made products offers several advantages beyond supporting domestic manufacturing.
Consistent Quality
Every Firestat duct high limit switch is manufactured using controlled production processes and is individually tested before leaving our facility. This helps ensure reliable performance when the switch is called upon during an over-temperature condition.
Faster Lead Times
Domestic manufacturing means shorter supply chains and more consistent availability compared to products that rely on overseas production.
Benefits include:
- Faster shipping
- Reduced supply chain disruptions
- Better inventory availability
- Responsive technical support
For contractors working against construction schedules or inspection deadlines, reduced lead times can make a significant difference.
Direct Access to the Manufacturer
Unlike many imported HVAC safety controls, Firestat customers can speak directly with the engineers and product specialists who manufacture the product.
Our team can help with:
- Product selection
- Temperature recommendations
- Probe length selection
- Custom configurations
- OEM applications
- Technical troubleshooting
Manufactured for Commercial HVAC Applications
Firestat duct high limit switches are commonly installed in:
- Apartment buildings
- Commercial office buildings
- Schools
- Hospitals
- Hotels
- Industrial facilities
- Electric duct heaters
- Air handling units
- Rooftop HVAC equipment
- Building automation systems
These controls help shut down HVAC equipment when duct temperatures exceed the selected set point, providing an independent layer of protection against overheating.
Firestat Features
Every Firestat duct high limit switch is designed for dependable operation and ease of installation.
Standard features include:
- Made in the USA
- Manual reset operation
- Adjustable models from 100°F–250°F
- Factory-calibrated fixed-temperature models
- 5″, 7.5″, and 11″ sensing element lengths
- Helix bi-metal sensing technology
- UL/cUL recognized
- Fast-acting snap-action switch
- OEM customization available
These options allow contractors and engineers to select a control tailored to virtually any commercial HVAC application.
Why Firestat Uses a Helix Bi-Metal Element
Firestat duct limit switches use a precision helix bi-metal sensing element that responds quickly to changes in duct air temperature.
As temperatures rise, the bi-metal element expands until it activates the internal snap-action switch. Depending on the wiring configuration, the control can:
- Shut down heating equipment
- Stop blower operation
- Close fire dampers
- Signal a building automation system
- Interrupt other connected safety circuits
Because the sensing element reacts rapidly to temperature changes, Firestat controls provide dependable protection in demanding HVAC environments.
OEM and Custom Manufacturing
Not every HVAC application requires a standard configuration.
Firestat offers custom solutions including:
- Custom trip temperatures
- Private labeling
- Custom probe lengths
- OEM manufacturing
- Special wiring configurations
- Volume production
If your application requires something beyond our standard product offering, our engineering team can work with you to develop the right solution.
Frequently Asked Questions
Where are Firestat duct limit switches manufactured?
Firestat duct high limit switches are manufactured by Senasys in Eau Claire, Wisconsin, USA.
Are Firestat switches UL recognized?
Yes. Firestat duct high limit switches are UL/cUL recognized for applicable models and are designed to meet industry safety requirements.
Do you offer adjustable and fixed-temperature models?
Yes. Firestat manufactures both adjustable and fixed-temperature duct high limit switches to meet a variety of HVAC applications.
Can OEMs purchase directly from Firestat?
Yes. We work directly with OEMs, contractors, distributors, and facility managers on standard and custom applications.
Visit our FAQ page for more common questions and answers.
Talk to a Product Specialist
Whether you need a replacement duct high limit switch, assistance selecting the proper sensing element length, or a custom OEM solution, our team is ready to help.
Contact Firestat today to discuss your application or request a quote.
