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Bi-metal, Snap Switch, and Snap Action Thermostats

Comstat maintains a large inventory of Honeywell Sensing and Control, formerly Elmwood Thermostats, lines of precision and commercial snap action thermostats. We are confident that with our stock list of custom and standard parts we will have a snap switch to meet your application requirements.

Our Inventory of Snap Action thermostat Products Includes:

Redi-Temp® Thermostats: a line of standard Elmwood thermostat products offered in a range of pre-set temperatures. These products are available standard for immediate delivery.

  • Redi-Temp Subminiature 3600 Series Thermostats in a TO-5 Package
  • Redi-Temp Series 3100 SPST Hermetic Series
  • Redi-Temp 3455 RC 15 A High Temperature Series




Precision Thermostats: Hermetic and non-hermetic devices for use in dispensing equipment, scientific instruments, aircraft, radar equipment, medical equipment and electronic control systems. Also available are custom-packaged thermostats for application flexibility and industrial-grade thermostats designed to operate in extreme environmental conditions.

  • 3100
  • 3106
  • 3150
  • 3156
  • 3000
  • 3001/3004
  • 3450, 3455R & 3455RBV
  • 3450RC & 3455RC
  • 3455RM & 3450CM



Commercial Thermostats: For use in a wide array of appliances, automotive applications, office machines, heat and smoke detectors and HVAC equipment. Snap action thermostats include automatic or manual reset options, phenolic or ceramic housings, and a variety of mounting brackets and terminal options.

  • 2450R, 2450HR, 2455R
  • 2450RC, 2450RCH, 2455RC
  • 2455RM, 2450CM
  • 2455RBV
  • 2450A, 2455RA
  • 2450R, 2455R, 2450RC, 2455RC




We have many Honeywell and Elmwood thermostat models in stock or compatible Comstat standard stock models available. Browse our inventory below and if you do not find the part you are looking for please contacts us and in most cases we will have a part to meet your needs.

What is a Snap Switch?

Snap Switch thermostats are bimetal mechanical thermostats that function via the thermal expansion and contraction of a bimetal disc that “snaps” from a convex to a concave shape at a set temperature. When the disc “snaps”, it either completes or interrupts a circuit, thus the term switch. Snap Switch aka Snap Disc thermostats have many practical applications. They are used in both heating and cooling applications to ensure the process temperatures do not exceed the thermal limits of the equipment or process. In some cases, snap acting thermostats with tight differential models can be used as the primary temperature control device. However, the most common application for a snap switch or snap action thermostat is as an over-temperature protection (or OTP) failsafe.

Because of their small size and low mass, the response time of snap switch thermostats is extremely rapid compared to other commercially available thermostatic devices. Additionally, the bimetal element of a Snap Disc does not carry the current, but acts as the force to open and close the contacts. Thus snap acting thermostats have a long life at relatively high currents – up to 16 amps for the ½ inch series – making snap switches the first choice of many OEMs.

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