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Table 3-4.1: Ethylene Glycol(Toxic)
Concentration
of ethylene
glycol (%)
Modification coefficient Minimum outdoor
temperature (°C)
Cooling capacity
modification
Power input
modification Water resistance Water flow
modification
0 1.000 1.000 1.000 1.000 0
10 0.984 0.998 1.118 1.019 -5
20 0.973 0.995 1.268 1.051 -15
30 0.965 0.992 1.482 1.092 -25
Table 3-4.2: Propylene Glycol(Low Toxic; Including the necessary inhibitors, classified as Category III according to EN1717)
Concentration
of propylene
glycol (%)
Modification coefficient Minimum outdoor
temperature (°C)
Cooling capacity
modification
Power input
modification Water resistance Water flow
modification
0 1.000 1.000 1.000 1.000 0
10 0.976 0.996 1.071 1.000 -4
20 0.961 0.992 1.189 1.016 -12
30 0.948 0.988 1.380 1.034 -20
Glycol absorbs water from its environment. Therefore do NOT add glycol that has been exposed to air. Leaving the cap off
the glycol container causes the concentration of water to increase. The glycol concentration is then lower than assumed.
As a result, the hydraulic components might freeze up after all. Take preventive actions to ensure a minimal exposure of
the glycol to air.
Due to the presence of glycol, corrosion of the system is possible. Uninhibited glycol will turn acidic under the influence of
oxygen. This process is accelerated by presence of copper and at higher temperatures. The acidic uninhibited glycol attacks
metal surfaces and forms galvanic corrosion cells that cause severe damage to the system. It is of extreme importance:
That the water treatment is correctly executed by a qualified water specialist.
That a glycol with corrosion inhibitors is selected to counteract acids formed by the oxidation of glycols.
That in case of an installation with a domestic hot water tank, only the use of propylene glycol is allowed. If the
system does NOT contain a domestic hot water tank, then you can use either propylene glycol or ethylene glycol;
That no automotive glycol is used because their corrosion inhibitors have a limited lifetime and contain silicates that
can foul or plug the system;
That galvanized piping is not used in glycol systems since it may lead to the precipitation of certain elements in the
glycol’s corrosion inhibitor;
To ensure that the glycol is compatible with the materials used in the system.
Protection against bursting: the glycol will prevent the piping from bursting, but NOT the liquid inside the piping from
freezing.
Protection against freezing: the glycol will prevent the liquid inside the piping from freezing.
The required concentration might differ depending on the type of glycol. ALWAYS compare the requirements from
the table above with the specifications provided by the glycol manufacturer. If necessary, meet the requirements set
by the glycol manufacturer.
If the liquid in the system is frozen, the pump will NOT be able to start. Mind that if you only prevent the system from
bursting, the liquid inside might still freeze.
When water is at standstill inside the system, the system is very likely to freeze and get damaged.
