Capillary Thermostats in Refrigeration Equipment

Refrigeration equipment plays a large role in our daily lives, from preserving food in our homes to maintaining the cold chain for perishable goods in various industries. To ensure these refrigeration systems operate efficiently and maintain their set temperatures, we use capillary thermostats. These small yet essential devices regulate temperature, ensuring the safe storage of goods and the smooth operation of refrigeration systems. For inquiries about OEM pricing on our STEMCO Capillary Thermostats, contact us.

Understanding Capillary Thermostats

What is a Capillary Thermostat?

A capillary thermostat is a temperature control device that uses a capillary tube filled with a temperature-sensitive fluid to regulate temperature in various applications. These thermostats consist of three main components: a temperature-sensing element, a control knob or dial, and a switching mechanism. The temperature-sensing element, often a fluid-filled bulb, sits at the end of a long, flexible capillary tube. The control knob allows users to set the desired temperature, while the switching mechanism controls the power supply to the refrigeration equipment based on temperature fluctuations. To learn more about our line of capillary thermostats, visit the product page.

Applications of Capillary Thermostats in Refrigeration Equipment

Domestic Refrigerators

Capillary thermostats commonly monitor and regulate temperature in domestic refrigerators and freezers. When the temperature inside the refrigerator rises above the set point, the capillary thermostat signals the compressor to start cooling. Conversely, when the desired temperature is reached, it shuts off the compressor to save energy.

Commercial Refrigeration

In commercial refrigeration equipment, such as walk-in coolers, reach-in freezers, and display cases, capillary thermostats maintain precise temperature control. These thermostats ensure that perishable goods are stored at the correct temperature to prevent spoilage and maintain food safety standards.

Industrial Refrigeration

Industrial refrigeration systems used in food processing, pharmaceuticals, and chemical industries rely on capillary thermostats to regulate temperature in large storage tanks, cold storage warehouses, and production facilities. Precise temperature control ensures product quality and safety.

Why Capillary Thermostats Are Preferred in Refrigeration Equipment

Stemco 351-253944 Capillary Thermostat


Capillary thermostats provide accurate temperature control, ensuring that the refrigeration equipment consistently maintains the desired temperature range. This accuracy preserves the quality and safety of perishable goods.


Capillary thermostats are known for their robust construction and reliability. They withstand the harsh conditions often encountered in refrigeration applications, such as temperature fluctuations, humidity, and vibration.


These thermostats offer a cost-effective solution compared to more complex temperature control systems. They provide reliability without the need for sophisticated electronic components.

Ease of Installation

Capillary thermostats are relatively easy to install and maintain, making them a practical choice for both residential and commercial refrigeration systems.

Capillary thermostats maintain desired temperatures effectively, making them essential for household refrigerators, commercial cooling systems, and industrial refrigeration. Additionally, their accuracy, durability, cost-effectiveness, and ease of installation ensure optimal performance across various applications. As technology advances, capillary thermostats will undoubtedly continue playing a key role in refrigeration systems.

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Bulb & Capillary Thermostats

Original equipment manufacturers worldwide use thermostat switches designed and manufactured by STEMCO, a Division of Senasys. No matter which style or model you choose, all of the capillary thermostat switches 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.

Ambient Compensation

Our capillary thermostats can be ambient compensated to offset the differential in temperature which keeps our thermostat controls more accurate as it’s environment changes.

Custom Options

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.