Deionized Water vs Distilled Water for Heat Transfer Applications

Heat transfer fluids are often diluted with water to achieve the appropriate freeze protection required, and sometimes systems are filled with water alone. Which type of water should be used- deionized water or distilled water?

Deionized WaterDeionized Water

Deionized water is produced by running water through an RO unit, resin bed system, or some similar piece of equipment. This purification process, sometimes referred to as ‘water polishing’, will strip out most impurities and ions in the water, but will leave some essential ions behind. This water is a good choice for using in heat transfer applications, because the impurities have been removed, but some essential ions are still present, which makes it less corrosive. When using deionized water for heat transfer applications, there are no issues with compromising the system, the integrity of the materials, the construction or any heat transfer fluid that may be used. Standard inhibitors can be used. It is also less costly to manufacture deionized water.

Distilled Water

When water is distilled, ALL impurities and ions are completely stripped out of it. Distilled water is truly pure water. However, it is also very ‘hungry’ for some essential ions that it is now lacking. The water will try to pull the necessary ions out of anything it comes into contact with, making it extremely corrosive. Although we don’t recommend using distilled water for heat transfer applications, it can be used, if it is used with the correct inhibitor package. This may mean that a bolstered inhibitor package will be necessary over a standard inhibitor package. If it is used without the correct inhibitor package, it will seek out the ions that it is ‘hungry’ for from the materials and construction in that system and it will begin to erode the system. Distilled water is also more expensive to manufacture. As a result, CORECHEM generally does not blend distilled water with our heat transfer fluids unless by special request.

With other questions about what type of water you should use in a heat transfer application, reach out to a heat transfer specialist today! Or, browse our heat transfer fluids here.

Do I Need To Treat My Closed Loop System for Organic Growth?

Geothermal Installation

Geothermal and chilled water closed loop systems need to be treated for organic growth. Here we offer tips on cleaning and treating your system, and discuss what happens if you don’t treat.

Initial Cleaning Post-Installation:

Closed loop systems should always be properly flushed and cleaned after the initial installation and before the first fill. Oil, debris, and slag left over from welding and construction of the system could easily be present and will circulate through the system after the initial fill if it is not cleaned out properly. When water or heat transfer fluids begin circulating and are then continuously in contact with the debris and contaminants, they begin to take on a microbiological character. Dissolved microbes in the water can turn into the start of corrosion and organic growth in the system.

Ongoing Treatment & Maintenance:

There are many ways leaks may develop in your system. They may develop unnoticed, or after a repair (i.e. digging up a geothermal loop). If dirt or air or any type of bacteria or contamination is allowed into your system through a leak and is not addressed, this is essentially asking for problems. We frequently receive samples of heat transfer fluids for testing that contain some kind of dirt, debris, or microbiological growth in them, as it is a common problem.


Tips on Cleaning and Treating a Closed Loop System to Prevent Organic Growth

After installation is complete, the system should be properly cleaned using either a sodium hypochlorite (bleach) solution or a closed loop system cleaner such as GlycoClean. This will ensure all contaminants are out of the loop prior to the initial fill. A good inhibition package such as GlycoHib I-50 should then be added to the water / glycol solution used in the initial fill. This will circulate in the system as long as the useful lifespan of the product has not been used up and will keep bacteria from growing that may enter the system through potential hidden leaks. In addition to killing off bacteria, it will also create a film on the inside of the pipes to ensure that nothing from the material in the pipe will break down and contaminate the system.

Annually, the fluid in your system should be analyzed, and if the fluid has been ‘spent’ (the useful lifespan used up), the fluid will need to be replaced.


What Happens If I Don’t Treat My System?

If a system is not properly maintained, it is highly likely that problems will begin to multiply over time. Organic growth and corrosion will eventually lead to system failure, pump failure, and/or decreased efficiency of the equipment as the heat transfer-ability of the fluid is lessened through contamination in the system.

With questions about treating your closed loop geothermal or chilled water system for organic growth, or getting your annual fluids analysis, contact us.

Geothermal Maintenance Made Easy

April 2, 2019

As warm weather returns, it’s time for your spring geothermal maintenance check-up!

At CORECHEM, we recommend you inspect your geothermal system at least once a year. Spring and fall are the most common times to do this. Test in the spring to look for post-winter issues; test in the fall to make sure your fluid concentration is high enough to prevent freezing.

Either way, it’s important to perform a check to detect any small issues your system may be having before they become big – and expensive.

First things first! Do an annual fluids test. A spring fluids test will help detect:

  • the presence of / potential for algae or mold growth (bio-fouling) prior to summer weather
  • the presence of /potential for corrosion
  • whether or not your fluid is ‘spent’
  • underground leaks (One good indicator of leaks is if you have red clay or excessive dirt in your geothermal fluid.)

CORECHEM is making is easy – and fast – to test the health of your geothermal system this spring! Call us today to have a geothermal maintenance test kit mailed to you. Your fluid will be tested for concentration, pH, and reserve alkalinity. Additional testing is performed as needed to further diagnose the health of your geothermal fluid. You should receive your results within 2 days of our receiving your sample!

It is also important to check:

      1. Filters. Clogged filters in your heat exchanger increase wear and tear on your pumps. (Ideally, we recommend checking these at least once a quarter.)
      2. Condensate drain. A clogged condensate drain will impede water flow – causing your pumps to work extra hard.
      3. For visible leaks.
      4. All of your heat pumps, fans, thermostat and other equipment. These should be tested to ensure they are working properly.
      5. Foliage overgrowth. Remove foliage to ensure nothing is obstructing your air intake.

At CORECHEM, we look forward to helping you bring your geothermal fluid up to speed. Call us today to discuss our geothermal fluid products including: glycols, alcohol-based fluids, and corrosion inhibitors.

Flu Shots … and Closed Loop System Checks

We all know that fall is a time to think about our flu shots, and that it is critical to maintain our health during the flu season. Have you considered checking the health of your customers’ closed loop HVAC and geothermal equipment, to ensure that it too stays healthy all season long? CORECHEM Inc. is your resource for analyzing thermal fluids, to give your customer the peace of mind that their systems contain enough antifreeze to protect from a freeze up flu.

Closed Loop System

Why Is It Important to Treat Your System with the Burst Protection Flu Shot?

Winter is once again on the brink, and just like humans, the health of your closed loops systems might suffer. CORECHEM’s GlycoChill+™ and Exo Endosol™ products provide both the freeze and corrosion resistance that your clients’ systems need to stay well all winter long.

From now until November 30, CORECHEM is offering thermal fluid analysis for any system, at no charge! Simply reach out to us at or call 865-524-4239 to have a sample kit shipped to you today. You should get your results within 2 days of the receipt of your sample!

Request a sample test

Geothermal Fluids – Is your system protected from biofouling and corrosion?

Geothermal Fluid Pump – Biofouling & Corrosion (photo courtesy of Ambient Geothermal)

While a system may contain a sufficient level of heat transfer fluid to prevent the system from freezing, what is often overlooked is the protection of the system from corrosion and biofouling.  When glycol-based heat transfer fluids are used in closed-loop geothermal systems, the risk of biofouling and corrosion is much higher than the risk of the fluid freezing.  To prevent system biofouling and corrosion the following recommendations should be taken into consideration.

  • Glycol-based heat transfer fluid concentrations above 20% will inhibit the growth of most microorganisms and fungi, the source of biofouling.
  • Inhibitors buffer the effects of organic acids that form due to the degradation of glycol. When using concentrated glycol-based heat transfer fluids ensure that the inhibitors are adequate at the dilution used.
  • Ensure that the system is properly flushed and purged of air before introducing the heat transfer fluids.
  • The use of deionized water will reduce the risk of bio-contamination from water.
  • After completing the installation of the heat transfer fluid allow the system to circulate for complete mixing and purge all air from the system.

CORECHEM Inc. is a manufacturer of glycol and alcohol based heat transfer fluids for commercial closed-loop HVAC and geothermal systems, our products provide protection, comfort and efficiency, for you and your clients.  Call us today for further information on preventing corrosion and biofouling.

Matthew Werle