Is Your Glycol System Ready for Winter?

As colder weather approaches, glycol systems become an important line of defence for mechanical equipment exposed to freezing conditions.

However, having glycol in the system does not automatically mean it is ready for winter. Concentration can change, inhibitors can become depleted, and the fluid itself can degrade over time. A system may still circulate normally while providing less protection than expected.

Fall testing gives facility teams and mechanical contractors time to identify problems, arrange the right products and complete any necessary corrections before temperatures drop.

Start With Glycol Concentration

Glycol lowers the freezing point of the fluid circulating through a system. The amount of protection depends on the glycol type and its concentration in water.

If the concentration is too low, the fluid may begin to freeze at a temperature the system could realistically experience. This is especially concerning for coils, piping and equipment located outdoors, near air intakes or in other areas exposed to cold conditions.

Concentration can decline when water is added following a leak, repair or maintenance activity. Even a relatively small amount of dilution can change the level of protection. If additions are not documented, operators may assume the original concentration is still present when it is not.

Testing should confirm the actual concentration and compare it with the protection required for the application. The target should account for expected temperatures, equipment location, system design and operating requirements.

More Glycol Is Not Always Better

Adding extra glycol may seem like a simple way to increase winter protection, but excessive concentration can create other problems.

Glycol is more viscous than water, particularly at lower temperatures. As concentration increases, the fluid can become more difficult to pump. This may reduce flow, increase pump energy requirements and affect heat transfer performance.

The goal is not to achieve the highest possible concentration. It is to maintain the correct concentration for the system and its operating conditions.

This is why accurate testing and professional guidance matter. Guessing based on the colour of the solution or the amount of product previously added cannot confirm the current level of protection.

WMC can help assess system conditions, water chemistry and operating requirements to recommend an appropriate glycol concentration and treatment approach.

Freeze Protection and Burst Protection Are Different

Facility teams should also understand the difference between a fluid’s freezing point and its burst protection.

The freezing point is the temperature at which ice crystals begin to form in the solution. Depending on concentration, the fluid may become slushy rather than freezing solid immediately. Burst protection refers to the lower temperature at which expansion could create enough pressure to damage piping or equipment.

A system designed to remain operational during cold weather may require protection against freezing, not simply protection against bursting. The correct target depends on what the system needs to do during winter conditions.

A qualified water treatment provider can help interpret concentration results in the context of the system rather than relying on a single temperature rating.

Glycol Management Is About More Than Freeze Protection

A glycol solution can test at the expected concentration and still be in poor condition.

Commercial heat transfer fluids normally contain corrosion inhibitors designed to protect the metals found throughout the system. These inhibitors do not last indefinitely. They can become depleted over time and may be affected by dilution, contamination or fluid degradation.

Heat, oxygen and prolonged service can contribute to glycol degradation. As the fluid breaks down, acidic compounds can form. A decline in pH and reserve alkalinity may indicate that the solution is losing its ability to protect system metals.

Improperly maintained glycol can contribute to rapid corrosion, fouling, bacteria growth, reduced heat transfer and premature equipment failure. This puts piping, pumps, heat exchangers and other critical components at risk even if the fluid still provides adequate freeze protection.

Effective glycol management must consider the overall fluid chemistry and system conditions, not just the concentration percentage.

Watch for Signs of Corrosion or Contamination

Fall testing should look beyond concentration to assess the overall condition of the system.

Discoloured or cloudy fluid may indicate corrosion products, suspended solids or contamination. Sediment in samples, blocked strainers and recurring pump seal issues can also point to a larger problem.

Laboratory analysis may evaluate pH, inhibitor condition, reserve alkalinity, metals and other characteristics relevant to the fluid and its application. Comparing results over time can help determine whether the system is stable or gradually deteriorating.

Operators should also inspect for leaks and review makeup records. A glycol system that regularly requires fluid or water additions likely has an issue that should be investigated. Frequent additions can dilute the glycol, introduce oxygen and reduce inhibitor levels.

WMC provides glycol quality assurance and laboratory analysis to help determine whether a system requires a concentration adjustment, additional corrosion control, cleaning or fluid replacement.

Know When the Glycol Needs Correction

Not every result outside the recommended range requires a complete fluid replacement. The appropriate response depends on what testing reveals.

A system with slightly low concentration and fluid that is otherwise in good condition may be corrected by adding the proper inhibited glycol solution. If inhibitor levels are low, a compatible inhibitor adjustment may be possible.

However, severely degraded, contaminated or improperly mixed fluid may require reclaiming or replacement. The system may also need to be cleaned and flushed before new fluid is added.

Compatibility is critical. Different glycol products and inhibitor packages should not be mixed without confirming they are suitable for use together. The quality of dilution water matters as well, since minerals and contaminants can affect fluid stability and system performance.

Simply adding fresh glycol to a badly degraded system may improve the concentration reading without resolving the underlying corrosion risk.

Calculate the Right Amount the First Time

Once a glycol system needs to be filled or corrected, determining the required volume is essential.

Ordering too little glycol can delay a project, especially during the busy fall season. Ordering too much can create unnecessary costs and storage challenges.

WMC’s online Glycol Calculator helps contractors estimate total system volume using pipe sizes, pipe lengths, expansion tanks, feed tanks and an appropriate buffer. It can also calculate how much fluid must be drained and replaced to achieve a desired concentration in an existing system.

These calculations help contractors plan more accurately before filling begins. WMC can also support glycol supply and delivery coordination, with products available in pails, drums, totes or tanker trucks depending on the project requirements.

Prepare Before Peak Glycol Season

Peak glycol season brings tight schedules, demanding projects and little room for error. Planning ahead can help prevent product shortages, incorrect quantities and project delays.

A complete winter readiness review should confirm:

• The glycol type and concentration
• The required level of freeze protection
• The pH and condition of the inhibitor package
• Whether corrosion products or contaminants are present
• Whether leaks or unplanned water additions have occurred
• Whether correction, cleaning, reclaiming or replacement is required
• The product volume and delivery format needed for the work

WMC supports glycol systems in commercial, institutional, industrial, residential and refrigeration applications. Whether you are commissioning a new system, correcting an existing concentration or replacing degraded fluid, our team can provide the technical guidance, products and field support needed to complete the work confidently and efficiently.

Contact WMC Water early to discuss your upcoming glycol requirements.