3/4″ Single Shot Snap Disc Thermostat

Senasys 2541 series of 3/4″ Single Shot Snap Disc Thermostats are specifically designed as high limit devices for applications where automatically resettable thermostats are not desirable. These reliable devises are especially well-suited for application in small & major applications, & industrial & high technology products.

custom options

Designed & manufactured to meet requirements of original equipment manufacturers worldwide.

high quality

Senasys products are 100% tested before they leave our facilities.


All of our snap disc units are UL approved (USR).

made in u.s.a.

Designed & manufactured in Eau Claire, WI, U.S.A.

For applications up to 40 Amps and 350ºF these single shot switches act a a high temperature limit switch in applications from food and beverage, to heating and industrial applications.

Our 3/4″ Single Shot Snap Disc Thermostats are created with bi-metal discs that react to temperature changes and ‘snap’ causing the circuit to  OPEN. These one shot thermostats act as a high limit temperature switch that won’t automatically reset. The 2541 Series are perfect for high amperage, one time use, safety limit switches.

Product Specifications

  • 3/4″ Bi-Metal Snap Action Disc
  • Single Shot Operation
  • Break on temperature rise
  • Single-pole, single-throw (SPST)
  • 40 Amps @ 240VAC, Single Shot Operation
  • High environmental exposure temperature of 0°F to 350°F
  • Available with exposed caps to provide a faster response time.
  • Available with a variety of mounting brackets 
  • Variety of terminal options available
  • UL listed
  • Made in U.S.A.

For a more economical solution, Senasys has built relationships with overseas suppliers to provide our customers thermostats at a lower cost, with the same high quality as our snap disc thermostats built in the U.S.A.

Mounting Options

With snap discs, different applications will require a different snap disc mounting style. Temperature switches can be installed in a variety of environments, and the right mounting bracket is needed to make sure that the switch is able to perform accurately. Even if a switch functions at the right temperature, the wrong bracket can cause it switch at the wrong time or even not switch at all. See a variety of available mounting options below, or click here to learn more.

If you need a style that isn’t shown here, contact us! We offer custom bracket options as well.

Select from a variety of mounting options below.

B501 Small Flange Direct Mount
B502 Large Flange Airstream Mount
B504 Large Flange Bracket Mount
B507 Notched Bracket, Surface Mount

Terminal Options

Our 2541 series is available with a variety of terminal options. Our standard terminals are 1/4″ Quick Connect Terminals or Screw Terminals.

A variety of terminal bends & orientations are also available. Our standard terminal bends are 0°, 45° or 90°.

Learn more about our terminal options available  here.

For other custom options, please contact us.

1/4″ Quick Connect Terminals
Screw Terminals

Common Applications

Our 3/4″ single shot snap disc thermostats are found in a variety of applications. Choose a category below to learn more.

Frequently Asked Questions


What is a bi-metal snap disc?

Our snap disc thermostats are created with bimetal discs in them that react to temperature changes (rise or fall) and ‘snap’ causing the circuit to open or close. We form our discs from one of three bimetal compositions. Click here to learn more.

How can I reset my single shot thermostat?

The switch won’t reset under normal circumstances, but it can be reset using extreme cold. The best way to do this is by using dry ice, which can be found at your local Walmart. The switch needs to get down to about -40°F to reset, so regular ice isn’t nearly cold enough. Just remember to be careful when handling dry ice, as it has a temperature of below -100°F.

Learn more about how to do so by reading this article.

When should an exposed snap disc cap be used?

One of the standout characteristics of an exposed cap is its’ use of a black exposed disc. This disc serves as a crucial element in sensing temperature fluctuations swiftly, enabling the switch to respond rapidly to environmental changes. This quick thermal response is especially important in applications where precise temperature control is paramount, such as in thermostats, industrial control systems, and appliances. The exposed caps are available for all non-epoxied snap disc thermostats within the Senasys catalog. 

For more information on exposed snap disc caps, click  here

When should gold contacts be used in place of silver?

One of the key advantages of gold contacts is their significantly lower contact resistance when compared to high-current silver contacts. This low resistance translates into improved electrical conductivity, allowing for smoother and more reliable signal transmission. This is especially important in applications where even the slightest interruption or distortion in the signal could lead to critical errors or malfunctions.

For more information on when gold contacts should be used, click  here

What is a flange mount?

When it comes to temperature monitoring, precision is key. The standard flange mount plays a vital role in achieving this precision by minimizing the distance between the sensor and the area being measured. This reduced gap ensures that temperature fluctuations are detected and recorded with remarkable accuracy, making it an indispensable tool in industries where temperature control is critical.

For more information on flange mounted snap disc thermostats, click  here

How are snap disc thermostats tested?

Senasys tests our snap disc thermostats through air, fluid, hot plate and other testing standards. Learn more about our quality inspection here.

My thermostat isn’t operating. What should I test first?

Continuity! Whether you have a hot or cold temperature thermostat, this test is easy and one of the first things we ask customers. Learn how to do so here.

What is the differential of a snap disc thermostat?

For these types of switches 10ºF is about the smallest range they can maintain cost effectively and consistently.

For complex systems actual testing is usually pretty important. We support this process by making it easy to test multiple package styles and disc temps in sequence or all at once just give us a call. Learn more about temperature differentials here.

What is the temperature tolerance of my snap disc thermostat?

Our standard tolerance is between 5°F to 10°F, but tighter tolerance options are available. We also offer a min/max type. Click here to learn more, or contact us with your requirements.

Where should I locate my thermostat when installing into my equipment?

The location of the temperature switch inside your heating element should be well thought through. Temperature will change in various locations within the system depending on the heating element location. The further you distance from the heating element, the lower the temperature. Where a temperature switch is located will determine how accurate it can measure and control the system. Senasys typically recommends with all of our temperature switches the closer you can get to the heating element the better for the most accurate reading and fastest response time.

Cross Reference

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2541 Series


60F/61F Series



3/4″ Bi-Metal Disc

Enclosed or Exposed

Single Shot
Fixed Temperature Range 0°F to 350°F

Open on Temp Rise

Single Pole, Single Throw


40 Amps @ 240VAC

One Shot

Variety of Mounting Options
Variety of Terminal Options
UL Listed
Made in U.S.A.

Build A Thermostat

Follow the below nomenclature guide to determine the 3/4″ single shot thermostat to meet your application requirements.

Other custom body & terminal options available, as well exposed disc and more.  Contact our technical support team to get started!

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