Siemens SINAMICS S120 Manual page 119

Antifreeze
The following can be used as antifreeze:
● Antifrogen N (manufacturer: Clariant) with a proportion X of 20% < X ≤ 45% is the anti-
freeze used. Coolants containing 45% Antifrogen N provide protection down to -30° C.
● Antifrogen L (manufacturer: Clariant) with a proportion X of 25% < X ≤ 48% is the anti-
freeze used. Coolants containing 48% Antifrogen L provide protection down to -30° C.
● Varidos FSK (manufacturer: Nalco) with a proportion X of 25 % < X ≤ 45 % is the anti-
freeze used. Coolants containing 45% Varidos FSK provide protection down to -30° C.
All agents contain anti-corrosion inhibitors which permanently protect the metal in the cooling
system against corrosion.
It is particularly important to ensure that the percentage of antifreeze when topping up the
cooling system always corresponds to the minimum quantity (20% or 25%), otherwise the
mixture becomes corrosive.
NOTICE
Damage caused by leaks if the appropriate concentration of antifreeze is not used
An insufficient concentration of antifreeze can result in material damage caused by
corrosion and cooling circuit leaks.
• Regularly check the antifreeze concentration. Add the appropriate amount of antifreeze
Biocide
Closed cooling circuits with soft water (°DH>4) are susceptible to microbes. The risk of
corrosion caused by microbes is virtually non-existent in chlorinated drinking water systems.
No strain of bacteria can survive when the appropriate quantity of antifreeze is added.
The following types of bacteria are encountered in practice:
● Slime-forming bacteria
● Corrosive bacteria
● Iron-depositing bacteria
The type of bacteria determines the suitability of a biocide. At least one water analysis per
annum (to determine the number of bacterial colonies) is recommended. Suitable biocides
are available from Nalco for example.
Cabinet Modules liquid cooled
Manual, 10/2015, A5E37067587A
when required.
Commissioning the cooling circuit
5.2 Coolant for the internal deionized water circuit
119