STEMCO Capillary Switch


Thermostat Switch – Fluid Filled Capillary Type

No matter which style or model you choose, all of the thermostats with capillary tube operate using the same physics. A fluid is encapsulated in a metal and when the temperature changes the fluid either expands or contracts. This fluid change moves a diaphragm which is in touch with a snap action switch and either opens or closes a circuit. Our capillary thermostats also offer the option of being ambient compensated to offset the differential in temperature which keeps our thermostat controls more accurate as it’s environment changes.

Thermowells and support tubes are also available with all models.

If you do not know the switching temperature of your system, make sure you look at our digital switch. It has precise measurements with tight tolerances and differentials!

All of the Stemco, Cemco and Essex International Capillary Thermostat switches built by Senasys can also be built to customer specifications. This insures you get the exact control you want without paying for features you don’t need. Please contact us to receive additional information on any of our switches in this series.


Contact us about STEMCO capillary thermostats.

SPDT Capillary Thermostats

SPDT Capillary Thermostats

Senasys offers a wide range of different single pole, double throw capillary thermostats. Available field adjustable or fixed, the capillary thermostats can be manually or automatically reset.


351-254288 Capillary Thermostat


DPDT Capillary Thermostats

Senasys offers the addition of a second switch (DPDT). The two switches can be a any combination of SPDT auto reset and/or SPST manual reset.


368 Capillary Diaphragm Assembly

Capillary Diaphragm Assemblies

The capillary diaphragm assemblies consist of a bulb, capillary tube and a diaphragm. The diaphragm is engineered for a specific movement at a give temperature change.


Thermowells and Support TubesThermowells & Support Tubes

Thermowells are tubular fitting used to protect temperature sensors commonly found in industrial processes.


Digital Temperature SwitchDigital Temperature Switch

Designed by Senasys, the D Series digital switch allows for fast, easy set points, limits and differentials. If you do not know the systems switching temperature purchase a digital switch for precise measurements with tight tolerances and differentials. 


Bi-metal Snap Disc Thermostat SwitchBimetal Snap Disc Thermostats

Senasys also designs and manufactures multiple types of bimetal snap disc thermostats. A bimetal snap disc thermostat switch is a temperature sensing device which is made with a formed 1/2″ or 3/4″ bi-metal disc that “snaps” at a preset temperature, -21-450°F.