We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.
DIY

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

What Is a Pneumatic Thermostat?

Andrew Kirmayer
By
Updated: May 16, 2024
Views: 11,570
References
Share

A pneumatic thermostat is a device that uses a tube filled with air to control the temperature of an air conditioning or heating system. When the temperature is set, the thermostat reacts to changes in temperature by reading the level of air pressure in the tube. If it gets warmer than the setting specified, the pressure level will trigger the system to activate until the air is cooled to the desired temperature. A heating system will activate in the same way if the temperature is cooler than the setting on the thermostat. When using a pneumatic thermostat, a mechanical or digital dial on the outside is turned to set the range.

The two main kinds of pneumatic thermostat include direct and reverse acting systems. Direct acting types of thermostats increase the pressure in the tube in proportion to the rise in temperature. In a reverse acting pneumatic thermostat, the pressure lowers when the temperature increases, while rises in pressure occur as it gets cooler. A controller serves as the connection between the pressure tube, the thermostat, and the rest of the system. This interface can be an electronic circuit, an actuator, or a pneumatic-electric switch that has a direct or reverse configuration.

Problems with the thermostat include blockages in the restrictor or nozzle, or a need for calibration. The supply or exhaust valve can be clogged, or the connections for the control and supply pressure reversed during installation. Repairing a pneumatic thermostat, if the control pressure stays at zero, typically requires nozzle cleaning or recalibration of the device. The restrictor might also need to be replaced. If the control and supply pressure remain basically equal, dirt can be clogging a nozzle or valve, so the blockage needs to be cleared and the thermostat re-calibrated.

When air leaks from the exhaust port of a pneumatic thermostat, then oftentimes the supply and return connections are wrong and need to be re-connected. The air going into the thermostat should be clean. Pressure levels should also be constant at around 20 to 30 psi, or pounds per square inch (about 1.7 to 2.1 bar). This can be measured using a test gauge along with a needle adapter.

When maintained and calibrated correctly, the pneumatic thermostat will respond accordingly to changes in temperature. It will also provide the desired control to keep the thermometer within the necessary range. The device can be used in the summer or winter, and its pressure levels can be set to activate the heating or cooling systems as needed.

Share
HomeQuestionsAnswered is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Link to Sources
Andrew Kirmayer
By Andrew Kirmayer
Andrew Kirmayer, a freelance writer with his own online writing business, creates engaging content across various industries and disciplines. With a degree in Creative Writing, he is skilled at writing compelling articles, blogs, press releases, website content, web copy, and more, all with the goal of making the web a more informative and engaging place for all audiences.
Discussion Comments
Andrew Kirmayer
Andrew Kirmayer
Andrew Kirmayer, a freelance writer with his own online writing business, creates engaging content across various...
Learn more
Share
https://www.homequestionsanswered.com/what-is-a-pneumatic-thermostat.htm
Copy this link
HomeQuestionsAnswered, in your inbox

Our latest articles, guides, and more, delivered daily.

HomeQuestionsAnswered, in your inbox

Our latest articles, guides, and more, delivered daily.