STEMCO, a division of senasys
1/2″ Epoxy Sealed Snap Disc Thermostats
Senasys’ 1/2″ epoxy sealed snap disc thermostats are designed for extended use in extreme environments , built using our patented metal sleeve rivet construction and sealed to protect against salt spray, water, moisture and heat .
Designed & manufactured to meet requirements of original equipment manufacturers worldwide.
Senasys products are 100% tested before they leave our facilities.
Senasys products are UL/cUL Recognized.
made in u.s.a.
Senasys products are designed & manufactured in Eau Claire, Wisconsin, U.S.A.
The 431 series 1/2″ epoxy sealed snap disc thermostats are used whenever a moisture or dustproof enclosure is required for safe, sensitive and reliable operation. A polypropylene boot enclosure filled with epoxy resin covers the thermostat. The bi-metal disc control element is in close proximity to the sensor cap to provide rapid response to temperature changes.
Since the bi-metal disc used in the Type 431 thermostat is thermally and electrically insulated the bi-metal disc reacts only to the temperature of the controlled device or medium surrounding the disc. Instantaneous, positive action of the disc prolongs thermostat life by minimizing arcing and eliminates chattering, false cycling and electrical interference with radio and television reception. Long life is assured with wiping contacts.
The temperature range determines when the thermal switch will close, or engage the electrical circuit, and when it will automatically reset, or open. A specific temperature range may be designed according to your application needs, or choose from our standard ranges.
- 1/2″ Bi-Metal Snap Action Disc
- High environmental exposure temperature range of -40°F to 200°F (-25°-105°C).
- Differential temperature range of 15-80°F (-9 – 25°C).
- Automatic Reset
- Single-pole, single-throw (SPST)
- Rated up to 15 Amps @ 120VAC, 100,000 cycles
- Variety of mounting options available such as pipe & stud mounts.
- Variety of wire lead options available, standard: 18AWG – 12″ or 72″, covered with 1/32″ or 1/16″ thick 100°C plastic insulation. Other custom wire leads, such as gauge, color, length, & connectors available. Contact us for more information.
- UL Approved
- 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.
Select from a variety of mounting options, including pipe and stud mounts.
Threaded Stud Mount
NPT Threaded Mount
Large Surface Mount
Standard Temperature Options
Below is a list of our common, off the shelf, bi-metal temperature options. Custom temperature options available. Please contact us.
Close 45°F ±5°F Open 34°F ±5°F
Close: 60°F ±5° Open: 50°F ±5°
Close 85°F ± 5°F Open 70°F ± 6°F
Close: 100°F ±5°F Open: 85°F ±5°F
Close 125°F ± 7°F Open 105°F ± 7°F
Close: 150°F ±5°F Open: 135°F ±5°F
Close: 175°F ±5°F Open: 160°F ±5°F
Close: 180°F ±5°F Open: 160°F ±5°F
Close: 190°F ±5°F Open: 175°F ±5°F
Close: 200°F ±5°F Open: 185°F ±5°F
Close: 220°F ±5°F Open: 200°F ±5°F
Close: 250°F ±5°F Open: 230°F ±5°F
Open 45°F ± 5°F Close 34°F ± 6°F
Open 60°F ±5°F Close 45°F ±5°F
Open 75°F ±5°F Close 60°F ±7°F
Open 100°F ± 5°F Close 85°F ± 5°F
Open 125°F ± 5°F, Close 105°F ±5°F
Open 150°F ±5°F Close 135°F ±5°F
Open 170°F ±7°F Close 155°F ±7°F
Open 180°F ± 5°F Close 155°F ± 5°F
Open 190°F ± 5°F Close 170°F ± 7°F
Open 200°F ±5°F Close 185°F ± 7°F
Open 220°F ±5°F Close 190°F ±8°F
Open 250°F ±5°F Close 230°F ±7°F
Our 431 series 1/2″ epoxy sealed snap disc thermostats are found in a variety of applications. Choose a category below to learn more.
Frequently Asked Questions
YOU’RE QUESTIONS, ANSWERED.
For small quantities, we can build anything from 0°F to 220°F. Contact us for higher temperatures.
A snap disc does not use any power. Instead it acts as a circuit breaker for a system.
The body of the switch is plastic, and the mounting cap is either steel, aluminum, or brass.
Our products are designed and manufactured in Eau Claire, WI, U.S.A., and sold globally! We also have relationships with suppliers overseas to provide a more low cost solution when required.
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.
Our standard wire leads are black, 18 AWG at 12″ or 72″ length. We recommend the 72″ length, and then cutting down to what you need. We have other options available including color, lengths and gauge sizes. Click here to learn more.
Senasys manufacturers two different lines of sealed thermal switches, 431 series and 2570 series, which are UL873 approved to be hermetically sealed. Our sealed snap disc thermal switches are commonly found in environments where condensation, dust or other material may be present.
Senasys performed a series of tests with our sealed thermostat switches by submerging them into fresh water and salt water. Click here to see the results!
We are certain of our position at the top so we’re comparing our product with other top products in the marketplace today.
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T16 & T17 Series
1/2″ Bi-Metal Disc
Temperature Range -40°F to 200°F
15 Amps at 120 VAC
Single Pole, Single Throw
Surface, Airstream, Pipe & Stud Mounting Options
Custom Wire & Termination Options
Made in U.S.A.
Build Your Thermostat
Follow the below nomenclature guide to determine the 431 series automatic reset thermostat to meet your application requirements.
Request A Quote
For technical support, price & availability, complete the form below. Our team of product specialists will follow up with you in 1-2 business days.