(715) 831-6353 info@senasys.com

Bulb and Capillary Thermostat Switches

Senasys manufactures a line of capillary thermostat switches which are adjustable thermostat switches. These switches are available automatic or manual reset with a temperature range of this and this.

Original equipment manufacturers worldwide use temperature sensing products designed and manufactured by Senasys Inc. No matter which style or model you choose, all of the capillary thermostats 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.

Commercial food equipment manufacturer’s incorporate Senasys’ high quality, UL approved capillary thermostat switches and control. Other important applications are pool and spa, HVAC equipment and products for the home.

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 our direct sales support to receive information on any of our switches.

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


The bulb is filled with a fluid that expands or contracts upon temperature change and is mounted in the material flow being sampled. It is typically larger in diameter. The capillary is a small tube that carries the fluid away from the bulb to the head. The head can be a diaphragm or bellow which moves with the changing temperatures… (read more)

Bulb and Capillary Thermostat


The bulb is a sealed metal tube filled with a fluid that expands or contracts upon temperature change. The probe is a bulb connected directly to a diaphragm or bellow. This is a portion of the bulb and capillary thermostat… (read more)

Probe Style Thermostats