Daikin EWYA004D2V3P Installer's Reference Manual page 68

8 | Piping installation
Installer reference guide
68
WARNING
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 the
presence of copper and high temperatures. The acidic uninhibited glycol attacks
metal surfaces and forms galvanic corrosion cells that cause severe damage to the
system. Therefore it is important that:
▪
the water treatment is correctly executed by a qualified water specialist,
▪
a glycol with corrosion inhibitors is selected to counteract acids formed by the
oxidation of glycols,
▪
no automotive glycol is used because their corrosion inhibitors have a limited
lifetime and contain silicates which can foul or plug the system,
▪
galvanized pipes are NOT used in glycol systems since the presence may lead to
the precipitation of certain components in the glycol's corrosion inhibitor.
NOTICE
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.
Types of glycol
The following types of glycol are allowed:
▪ Ethylene glycol;
▪ Propylene glycol, including the necessary inhibitors, classified as Category III
according to EN1717.
Required concentration of glycol
The required concentration of glycol depends on the lowest expected outdoor
temperature, and on whether you want to protect the system from bursting or
from freezing. To prevent the system from freezing, more glycol is required.
Add glycol according to the table below.
Lowest expected outdoor
temperature
–5°C
–10°C
–15°C
–20°C
–25°C
–30°C
INFORMATION
▪
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.
Prevent from bursting
10%
15%
20%
25%
30%
35%
Prevent from freezing
15%
25%
35%
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EWAA004~008D + EWYA004~008D
Packaged air-cooled water chillers
and packaged air to water heat pumps
4P688013-1B – 2022.09