Marine Installation Manual
2021-08
4-15
4 Ancillary Systems
4.2 Cooling water system
X72DF
4.2.5
Cooling water treatment
Correct treatment of the low- and high-temperature cooling water is essential for
safe engine operation. Demineralised water or condensate according to the spec
-
ifications in
must be used as raw water. In the event of an emergency,
tap water may be used for a limited period, but afterwards the entire cylinder
cooling water system must be drained off, flushed, and recharged with deminer
-
alised water.
Table 4
-
2
Recommended specifications for raw water
Corrosion inhibitors
In addition, the water used must be treated with a suitable corrosion inhibitor to
prevent corrosive attack, sludge formation and scale deposits. For details refer to
the chemical supply companies. Monitoring the level of the corrosion inhibitor
and water softness is essential to prevent down-times due to component failures
resulting from corrosion or impaired heat transfer.
For further information about permissible cooling water additives please refer to
the document
Cooling water and additives
, which is provided on the WinGD
webpage under the following link:
Parameter
Value
pH at 20°C
6.5 to 8.5
Max. dH
10° (corresponds to 180mg/l CaCO
3
)
a)
a) In the case of higher values the water must be softened.
Max. chloride
80mg/l
Max. sulphates
150mg/l
NOTE
Raw water from reverse osmosis technologies requires a minimum pH
value of 6.0.
NOTE
No internally galvanised steel pipes should be used in connection with
treated freshwater, since most corrosion inhibitors have a nitrite base.
Nitrites attack the zinc lining of galvanised piping and create sludge.
