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Why Carbon Dioxide Regulators Freeze

September 27, 2020

  • Why Regulators Freeze
  • Preventing Freezing Regulators

CO2 Regulator Freezing

Carbon Dioxide (CO2) regulator dry (left) and freezing up (right) based on the ambient temperature and pressure build-up. Image by RMK.

Why Regulators Freeze

Carbon dioxide (CO2) regulators sit at the top of your CO2 tanks. Carbon dioxide regulators commonly freeze up throughout the year depending on the environment that your CO2 tanks are in and the amount of pressure passing through the CO2 regulator from the tanks. These conditions are created when the environment is warm enough to increase the internal pressure of the tanks, but the amount of gas being released and the pressure it is building up (working pressure) is lower than the pressure inside the tanks. This creates a condition where the high pressure inlet and low pressure outlet causes a drop in the temperature of the CO2 gas causing it to freeze and form dry ice around and on the CO2 regulator. The difference in pressure from 1000 PSI to 500 PSI can drop the temperature as much as 50-100 degrees fahrenheit especially if it is a liquid turning to a gaseous state. The changes of carbon dioxide can be illustrated with a CO2 phase diagram. The form of CO2 that is stored in the tanks can either be gaseous or liquid. The dry ice or solid carbon dioxide, is the frost that you see forming up on and around a CO2 regulator. If the conditions worsen, then the freezing can occur in the internal components and cause a blockage in the flow of CO2 gas to your grow rooms.

CO2 Phase Diagram

Carbon dioxide phase diagram from Geological and Mineral CO2 Sequestration Options: A Technical Review by Danae Voormeij & George J. Simandl (2010).

Preventing Freezing Regulators

There are a few options to remediate the issue of carbon dioxide regulators freezing up. One solution is to utilize a heated regulator, but these can be expensive and may not be required depending on the size and setup of your carbon dioxide distribution system. Another solution is to reduce the working pressure from your CO2 tanks to your regulator, but the pressure can change as the tanks are refilled which would require a constant adjustment of the working pressure. If you utilize a third-party service such as Green CO2 systems you could place a service call so that a field technician could come on-site, audit equipment, and resolve any issues you may have with their equipment. Additionally, field technicians perform semi-annual audits of their equipment to ensure that everything is working properly. There is a significant number of indoor cannabis cultivation facilities that utilize Green CO2 systems equipment and services because of the high level of sophistication that is involved.

"High pressure inlet and low pressure outlet can cause a drop in the temperature of the carbon dioxide gas causing it to freeze and form dry ice around your regulator."


  1. jimt. (2017). “Carbon Dioxide Regulators Freezing”. Gentec Genstar Technologies.

  2. David Gailey. (2020). “CO2 Freeze Up: Why it happens, what you can do”. Harris Products Group.

  3. (n.d.). “Technical Note Avoiding Regulator Freeze-up”. Aqua Environment Inc.

  4. Danae Voormeij & George J. Simandl. (2010). “Carbon dioxide phase diagram”. Geological and Mineral CO2 Sequestration Options: A Technical Review.

  5. (n.d.). Green CO2 Systems. “Cultivation Industry Brochure”.

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