Julian Klauza

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How to properly fill installations with antifreeze?

For many years, the common practice was to rely on water to operate heating installations. However, it quickly became apparent that this had serious drawbacks. First and foremost, during the winter season, the absence of residents and the resulting lack of heating activation can lead to water freezing in pipes and damaging the entire installation. Moreover, the presence of regular water in the installation promotes corrosion, which seriously weakens the structure of the pipes. Therefore, the use of glycol-based antifreeze fluids became a much better alternative. A wide selection of such products allows finding a solution adapted to a specific type of installation. Of course, the selection of the fluid is one thing, but an equally important issue is the proper filling of the installation with the purchased product. Therefore, in this article, we will describe this issue.

There are many myths and half-truths surrounding the use of antifreeze fluids. For this reason, we want to start by answering the question about the benefits of using such products.

As is known, one of the basic properties of water is that it freezes at a temperature below 0°Celsius. Freezing water leads to an increase in pressure in the installation, which in turn is the cause of microcracks. Microcracks can lead to damage to the installation, and even to flooding the house. Therefore, it is important to prevent such situations. One solution is to use properly selected glycol-based antifreeze fluid, such as mono-propylene or mono-ethylene glycol, which, thanks to its properties, prevents water from freezing.

It is worth mentioning one more significant advantage of using antifreeze fluids. Thanks to specially selected additives, glycol-based antifreeze fluids not only protect installations from freezing but also prevent corrosion.

Now let’s move on to the procedure itself.

Step 1 – emptying the installation

The first step (in the case of an already operating installation) will be to empty it. It is worth noting here that there is no predetermined time for replacing the fluid in the installation. How long the fluid will fulfill its function depends on many factors. That is why it is worth carrying out cyclical tests of the fluid in the installation.

What about new installations that have never worked before? In this case, we skip step 1 and move straight to step 2, which is the use of the flush.

Some may now wonder if, in case of need, antifreeze fluid can simply be added to the installation. Yes, it is possible, but it should be remembered that this is recommended only in a few cases, and incorrectly performed procedures of this type can do more harm than good. More information on this topic can be found in one of our articles.

Step 2 – use of the flush

Procold company offers specialized flush products called FLUSH. These are high-class products intended for use directly after installation or before filling it with a preparation containing glycol. Flush works on several very important levels. On the one hand, it performs a conserving function and protects the new medium from corrosion and the action of unfavorable factors. On the other hand, such a rinse cleans the installation well and can also be used for testing the tightness of the installation.

Step 3 – filling the installation with non-freezing fluid

The procedure for filling the installation with non-freezing fluid varies depending on the type of installation. Owners of open systems are in the best situation. They can easily access the main filling valve and fill the installation using a pump.

Filling a closed system installation is definitely more problematic. Often, a special filling station must be used.

Regardless of whether it is a closed or open installation, the best solution may be to call in a specialist to ensure that the entire procedure is carried out correctly.


Choosing the right product is also a very important aspect. On the market, there are fluids containing monoethylene glycol or monopropylene glycol. What is the difference between these substances? Monoethylene glycol is a cheaper alternative that has very good physicochemical properties. However, it has a less favorable safety profile and its use in places where it can come into contact with people, animals, or soil in the event of a leak is very dangerous and irresponsible. Therefore, safer monopropylene glycol should be used in household installations, which also has very good physicochemical properties, but is more expensive than monoethylene glycol due to its environmental friendliness.

Some time ago, we introduced FACTORY GLY to the market, a substitute for non-freezing fluid based on monopropylene glycol, which is about 30-40% cheaper than monoethylene glycol.

It is also important to maintain the appropriate level of glycol in the installation. Why is this so important? The answer can be found in our blog post.

When it comes to choosing a product, we encourage you to familiarize yourself with the Procold’s range of fluids. Our offer includes concentrates and ready-to-use fluids with different characteristics that are adapted to specific types of installations. For example, the FACTORY EKO fluid is very versatile and works well in installations such as heat pumps, refrigeration installations, and solar collectors.

When choosing a concentrate, it is crucial to dilute it correctly with demineralized water.

The final step will be to introduce the glycol-based fluid into the installation and then vent the radiators.

What are the consequences of incorrect installation filling?

A common mistake when filling the installation with glycol is to disrupt the aforementioned proportions. Excessive glycol concentration can have a negative effect on the condition of boilers and the installation itself. For the same reason, you should never add non-freezing fluid to a medium that is already in the installation without proper testing.

Of course, the same applies in the opposite direction. Too low glycol level can make the fluid not achieve the desired properties, which will result in a decrease in its effectiveness. Therefore, this is a significant risk that should be avoided.

back 2023-01-31