Water Quality Matters in Heat Transfer Solutions

March 7, 2020

bulk deionized water at goglycolpros.comWhen it comes to heat transfer solutions (a glycol and water mixture), you might be surprised to learn that selecting the right glycol is only part of the task. The type of water you use to fill your HVAC system can also play a big role in system efficiency and lifespan.

What is Deionized Water (DI Water)?
Dow® Chemical Company recommends the use of good quality water for dilution purposes, such as deionized water. Deionization is a process designed to remove impurities from water that will be used in heat transfer systems. It does this by extracting corrosive ions and scale promoters. The result of this process is a water that meets the purity standards to maintain peak system performance when paired with equally pure inhibited glycol heat transfer fluid such as DOWFROST,™ DOWFROST™ HD or DOWTHERM™ SR-1.

Why Hard Water Can Mean Trouble

Where hard water (also city water or plain water) is used to dilute industrially inhibited glycol concentrates, the inhibitor will react with the ions in the water and fall out of the solution. This forms sludge and sediment that reduce heat transfer efficiency and can lead to fouling and corrosion. This is due to greater levels of "hard water ions" (calcium and magnesium).

Impurities found in hard water can increase:

  • Metal corrosion
  • Pitting of cast iron and steel
  • Inhibitor depletion rate
  • Formation of scale and other deposits on heat transfer surfaces
  • Clogging of system components

And can reduce:

  • The effectiveness of corrosion inhibitors

To avoid these potential issues, Dow recommends that water used for dilution purposes meet the below minimum specifications.

Dow Chemical Deionized Water Demineralized Water Distilled Water Requirements

Don't Panic if You've Already Filled with Hard Water

If you've already filled your system with hard water, all is not lost. Dow has taken steps to help counteract the effects of hard water by including patented anti-scaling and hard water stabilizing technology in DOWTHERM SR-1 ethylene glycol and DOWFROST HD propylene glycol. Their patented additive enables these fluids to work effectively in solutions with hard water. However, other contaminants will still be present in the hard water, so when you can use deionized, demineralized or suitably pure water, be sure to do so. 

Note: The anti-scaling and hard water stabilizing additives are not included in DOWFROST food grade propylene glycol.

Demineralized Water Vs. Deionized Water

Deionization and demineralization, while being similar, have key differences. Deionization removes ionized salt from the water. Demineralization removes minerals from the water such as calcium, magnesium and many others. Much of the drinking water that we consume goes through both processes. Both can be used in heat transfer fluids and are superior to using plain or hard water. 

Where to Buy Deionized Water (Buy DI Water)

Go Glycol Pros is a deionized water supplier. We offer bulk deionized water for sale in 5 gallon pails, 55 gallon drums and 275 gallon totes here.

If you have questions about fill water or your current HVAC project, contact us. Our experienced customer service team has the product, system and HVAC know-how to assist you. 

Go Glycol Pros LogoGo Glycol Pros is a distributor of DOW® heat transfer fluid for over 20 years. We sell glycol online with no accounts or order minimums required. Available in 275 gallon tote, 55 gallon drum or 5 gallon pail, high purity DOW antifreeze is premixed with deionized water (DI water) at our in-house facility and ships out within just one business day. Our inhibited glycols include: DOWFROST HD propylene glycol, DOWFROST food grade propylene glycol and DOWTHERM SR-1 ethylene glycol.

Explore more helpful tips and advice at goglycolpros.com. Our knowledgeable glycol experts are ready to help you with your latest hydronic HVAC project.

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Disclaimer: Go Glycol Pros and it’s affiliates can not be held liable for issues caused by use of the information on this page. While the- information comes from many years of experience and can be a valuable tool, it may not take into account special circumstances in your system and we therefore can not take responsibility for actions that result from this information. Please feel free to contact us if you do have any questions.