How to Use A Refractometer to Test Glycol Concentration

Mike Kennedy
September 30, 2019
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A hydronic heating or cooling system is one of the most efficient types of systems when it comes to providing comfort for a building. Thanks to the serviceability of the major components, a building owner can maintain their system for optimal efficiency and system life.

When servicing hydronic equipment these steps are commonly taken; the equipment is isolated, system fluid drained, maintenance performed, and fluid is replaced.  What can happen with a glycol system? The potential exists for the glycol concentration to be less than design.  In a system with diluted glycol, we can see an undesired performance, a reduction of corrosion inhibitors, and (for colder climates) a reduction in freeze/burst protection. Please view the below video on how to test your system with a refractometer.


Upon completing your test and determining your system needs attention, please call R.L. Deppmann.  We will be able to assist you with getting the glycol concentration back to desired levels. You can also visit our Glycol page on the R.L. Deppmann website for more information.