Ozonia CFS Ozone Generator Tech Notes

Oxidation Technologies repairs, refurbishes, and sells used ozone generators.  Through our years of work with many brands of ozone generators we have learned many ticks of the trade that we feel are very valuable.  Our goal is to share this information with our customers and friends to promote the long term operation of every ozone installation.

This document is intended to help you get the most life out of your CFS-series Ozonia Ozone Generator. Whether used or new; following the advice outlined below will allow you to have a reliable and smooth running Ozone Generator for many years.

The operating instructions and advice found in this document serve as an addition to the Ozonia operator’s instructions. If these guidelines are followed, the CFS Ozone Generator can offer many years of reliable operation.



Ozonia has produced the CFS series Ozone Generator for over 20 years. They are some of the most popular water cooled Ozone Generators on the market today.

There are 2 main styles of these Ozone Generators:

  • Horizontal tube machines – older CFS-1, 2, 3, 7’s were configured with the Ozone Generator cells mounted in a horizontal fashion. These were produced with 1, 2, 3, or 7 Ozone Generator cells installed.
  • Vertical tube machines – newer CFS units using model CFS-2G-1, 3, 7, 14 were configured with the Ozone Generator cells mounted in a vertical fashion. These were produced with 1, 3, 7, or 14 Ozone Generator cells installed.

The same fundamental cell design and electronics have been used since the inception of the Ozonia CFS Ozone Generators. These are ceramic coated dielectric tubes sealed in a stainless steel corona cell. High voltage open coil style transformer is used at a frequency of ~1,500 Hz.

Repair and replacement parts are available from Ozonia and from the aftermarket for all of the CFS series Ozone Generators. For parts or repair, Oxidation Technologies can supply either original OEM or aftermarket parts for most all parts used in any Ozonia CFS Ozone Generator.


Corona cell

The corona cells used in the CFS Ozone Generators consist of a stainless tube with a ceramic coating on the tube that acts as the dielectric barrier to create the corona discharge. This ceramic coating cannot be repaired. If this ceramic coating is damaged the corona cell must be replaced.

Take care to keep your corona cell clean and dry at all times. Dirt, debris, or moisture on the dielectric will cause a hot spot and “pop” the ceramic coating off the stainless tube. This will create an un-repairable short in the cell and it must be replaced. There is no repair.

Aftermarket corona cells use dielectric tubes that can be replaced inside the corona cell. However, if this dielectric tube GOES BAD?, it cannot be repaired and must be replaced.


Corona cell purging

Ozonia requires that the Ozone Generator be purged with oxygen or air feed-gas (for between a few hours and 24 hours depending on conditions). It is our recommendation that the purge starts BEFORE cooling water is turned ON to prevent any condensation inside the corona cell. If the corona cell was open to ambient air that may have humidity in it, then cooling water is started, it is possible to create condensation on the dielectric tube. This condensation is difficult to completely remove during the purge cycle. If the Ozone Generator is purged for 1 hour prior to flowing cooling water it will prevent condensation.

The Ozonia Ozone Generator cannot be purged too long. We suggest purging your Ozone Generator with oxygen or dry air for at least 12 hours prior to operation.



An advantage of the CFS series Ozone Generator is that it can produce ozone efficiently from dry air or oxygen. However, it is very challenging, if not impossible, to maintain dry air that is pure enough and dry enough to not damage the Ozonia corona cell. Therefore, we recommend operating the CFS Ozone Generator on oxygen feed-gas only.


Cooling water (horizontal tubes only)

In the horizontal tube Ozone Generators it is important to remove any air pockets in the Ozone Generator cells. The cells will create air pockets along the top of the tubes, even with high cooling water flow-rates. The change is that there is no way for this water to escape. It is our belief that this is the main catalyst for the change to vertical tube orientation.

After cooling water is flowing, gently tilt the Ozone Generator to a 45-degree angle, front to back, to remove air pockets from the corona cells. Perform this tilt in both directions and this should remove all the air pockets from cooling water jackets around the corona cells.

Keep the cooling water circuit closed to ensure no air can enter the system at any times.


Power setting

The Ozonia Ozone Generators certainly offer the ozone production that they are advertised to make. We have found that 90-100% of rated ozone production is realized at a power setting of 70-75%. Power settings above 75% do not increase ozone production in any case other than the highest gas flow rate situations.

Due to the fact there is a diminished return on power input to the Ozone Generator cells, we suggest never operating an Ozonia CFS Ozone Generator at a power setting above 80%. It’s best to maintain a power setting as low as possible while still achieving the required oxidation in your application.

It is our experience that transformers and inverters overheat, and due to heat build-up in CFS series Ozone Generators, the overheated corona cells damage the dielectrics first. This can be avoided by following the power guidelines above.


Ozonia CFS series Ozone Generators can offer many years of reliable service if treated properly. We have seen these Ozone Generators in service for over 10 years with no failures of any parts whatsoever. If the Ozone Generator is purged properly, feed-gas is clean, and is run at a reasonable power setting with good cooling water, there is no reason the CFS series Ozone Generator will ever fail.

Should you have questions or are in need of service, please feel free to contact us.