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Glycol-based heat recovery and condensing systems

The maintenance of glycol-based heat recovery and condensing systems is often neglected. The systems are expected to function for as long as there is some heat transfer liquid in them. However, all heat transfer liquids disintegrate over time. If the liquid is in contact with oxygen, it may disintegrate rather quickly. Also corrosion inhibitors lose their efficiency.

Insufficient maintenance together with the disintegration of heat transfer liquids and corrosion inhibitors speed up corrosion and scale formation. They cause leaks in the system and failures in the function of devices. The pH value drops and the heat transfer capacity of the system is reduced.

System surveys and analytical services

The condition of glycol-based heat recovery and condensing systems is discovered by means of water analyses. The results are reported to the customer (analysis report).

The customer also receives system-specific recommendations for future action and a cost estimate for the required maintenance.

Maintenance services

Commissioning or renovation cleaning and glycol filling

A heat recovery or a condensing system is cleaned chemically (commissioning or renovation cleaning). The system is filled with a long-lasting antifreeze/anticorrosive agent (glycol or glycol solution) which contains a corrosion inhibitor. These procedures restore the heat transfer capacity of the system. They also ensure that the system and its devices work as planned and without interruption.

Verifying the glycol quality

The quality of the antifreeze/anticorrosive agent (monoethylene/monopropylene glycol) is verified. This procedure ensures that the capacity of the equipment is sufficient and secures the planned heat transfer capacity. Heat recovery and condensing systems must always contain the type of glycol specified in the original plan – monoethylene glycol or monopropylene glycol.  

Checking the glycol content

The frost resistance capacity and the optimal efficiency ratio are assured by checking the glycol content in the system. The glycol content has to correspond to the value specified in the original plan. The corrosion protection level of the system can be improved by adjusting the content of the corrosion inhibitor. This procedure extends the lifetime of the antifreeze/anticorrosive agent.

Filtration of solids

Detrimental solids are removed from the system by filtration. Solids may cause blockages and defects in the devices installed in the system. Filtration improves the quality of heat transfer liquids and ensures the smooth operation of devices.

Glycol filling stations

Our product range includes filling stations for glycol solutions. They are used to facilitate the adjustment of the glycol content and to keep the reserve glycol clean.

Recycling of glycol solutions

For recycling we accept aged ethylene and propylene glycol solutions, which contain at least 20 % glycol and which do not contain any oil. These solutions are cleaned and recycled by our partner. If a water-glycol solution contains large quantities of heavy metals, it is categorized as hazardous waste. Glycols and water-glycol solutions must be disposed of according to local regulations.


The customer receives a report on all the maintenance procedures that have been carried out. The report can be attached to the maintenance manual of the building.

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