cemco duct limit switches
The Firestat Duct Limit Thermostat Switches operate using the same physics to ensure HVAC safety. A helix bi-metal element senses a rapid temperature change. When the temperature changes the bi-metal expands and triggers a snap action switch and either opens or closes a circuit. These switches are commonly installed in air ducts designed to shut down heating, air conditioning and ventilation equipment in apartment complexes and other multiple dwelling units when air temperature exceeds the set point.
CERTIFICATION
UL Approved
Meets requirements in Section 607.3.1. of the North Carolina Mechanical Building Code.
CUSTOM OPTIONS
Firestat thermostat switches are built to customer specifications. Custom options available, such as, temperature ranges, element lengths & fixed temperatures.
MADE IN THE U.S.A.
Senasys takes pride in quality control and reliable operation of our components.
Every switch is individually 100% tested before it leaves the plant.
SAFETY
Safety is our priority. Firestats are a great addition to apartment complexes to ensure safety from hazardous situations in HVAC air ducts.
The Duct High Temperature Switches feature a helix bimetal element that senses rapid increases in duct temperature, such as those caused by fire. The high temperature limit operates an SPST switch that opens with a rise in temperature. A manual reset button reactivates the temperature limit after the high-temperature condition has cleared. These duct high temperature limits are indispensable in specialized HVAC applications and Building Automation Systems.
These Firestat models are field adjustable with a temperature range of 100°-250°F. The Models TC-205 Duct High Temperature Limits are Fixed Temp with a 5″ insertion element.
The enclosure has an ambient temperature of -40°F to 190°F. And the element’s ambient temperature is 350°F.
At Senasys, price and lead time is quantity based and units are made to order. To get the best possible price and lead time we recommend sending in a request for quote with your estimated annual usage to our inside sales team for quantities greater than 100.

ADJUSTABLE DUCT LIMIT CONTROL SWITCH
The TC Duct Limit Controls contain a Helix Bi-Metal that senses rapid increases in duct temperature such as fire. The Bi-Metal causes the normally closed contacts to open & turn off the power
Our adjustable option is available with a 5″, 7.5″ or 11″ insertion element.
PRODUCT SPECIFICATIONS
Setpoint Temperature Range: 100°F to 250°F
Reset: Manual Reset
Voltage: 120-240 VAC
Amp Rating: 4.9 FLA @ 240 VAC / 9.8 FLA @ 120 VAC / 29.4 LRA @ 240 VAC / 58.8 LRA @ 240 VAC
Temperature Sensor: Helix Bi-Metal
PURCHASE
View product to purchase online, or contact us for quantity based pricing.
FIXED DUCT LIMIT CONTROL SWITCH
The TC Duct Limit Controls contain a Helix Bi-Metal that senses rapid increases in duct temperature such as fire. The Bi-Metal causes the normally closed contacts to open & turn off the power
Our standard fixed temperature limit switch is available with a 5″ insertion element.
PRODUCT SPECIFICATIONS
Fixed Temperature Setpoints: 125°F, 165°F or 200°F
Reset: Manual Reset
Voltage: 120-240 VAC
Amp Rating: 4.9 FLA @ 240 VAC / 9.8 FLA @ 120 VAC / 29.4 LRA @ 240 VAC / 58.8 LRA @ 240 VAC
Temperature Sensor: Helix Bi-Metal
PURCHASE
View product to purchase online, or contact us for quantity based pricing.
Other custom temperature & element length options are available, please contact us.

DUCT FAN & LIMIT SWITCH
Senasys is currently working on the R&D for other duct limit controls possibilities. Our current product offering for the TC Series only opens on temperature rise. We are looking at other possibilities such as close on temperature rise and a SPDT switch, which will open and close two sets of contacts on temperature rise.
As we finalize the product, we’ll update our current customers and make it available.
Stay in the know, submit your e-mail.
Testimonials
We are always looking for our customer’s feedback. If you’d like to leave us a review to be posted online, please email us at info@senasys.com.
Purchased one of these units for my furnace. It is a quality product and great customer service provided as well.
Tyler A.
Home Owner
We needed 11 duct controls for an inspection of an apartment building. Company was easy to work with and helped us find what we needed to pass the inspection.
Alex R.
Contractor
Do you sometimes have the feeling that you’re running into the same obstacles over and over again? Many of my conflicts have the same feel to them, like “Hey, I think I’ve been here before”
John Doe
Company Name