15
English
4 - Installation (continued)
4.3 Internal/external Water Circuit
The flow switch and the filter water, although not included in
the supply, must always be fitted such as plant components.
Their installation is mandatory for warranty.
WARNING
The internal/external water circuit shall guarantee
a constant water flow rate through the circulating
refrigerant/water heat exchangers under steady
operating conditions and in case of a load
variation.
The circuit shall be composed by the following elements:
Q
A circulation pump which can ensure the necessary flow rate
and head.
Q
The total content of the primary water circuit shall never be lower
than 5 l/kW in terms of refrigerating capacity. If the total water
volume in the primary circuit should be unable to reach such
a value, an additional heat-insulated storage tank should be
installed. This tank is intended to avoid any repetitive start of the
compressor.
Q
A membrane expansion tank complete with a safety valve and a
drain which shall be visible.
NOTE
The expansion tank shall be dimensioned in such
a way that it can absorb a 2% expansion of the
total volume of the water in the plant (exchanger,
pipelines, uses and storage tank, if available).
The expansion tank shall never be insulated
when the circulating fluid is not flowing through
it.
A water pressure differential switch is mounted as a standard. It will
stop the unit whenever a flow rate problem occurs.
In addition:
Q
Install on/off valves (accessory) on the lines at the inlet and
outlet of the manifolds of the exchangers.
Q
Arrange a by-pass complete with an on/off valve between the
manifolds of the heat exchangers.
Q
Arrange air vent valves at the high points of the water lines.
Q
Arrange drain points complete with plugs, clocks, etc. in the
proximity of the low points of the water lines.
Q
Insulate the water lines to prevent the heat from blowing back
into the unit.
RECOMMENDED WATER COMPOSITION
PH
7,5 - 9
Electrical conductivity
10 - 500
µS/cm
Total hardness
4,5 - 8,5
dH
Temperature
< 60
[°C]
Alkalinity (HCO
3
-
)
70-300
ppm
Alkalinity / Sulphates (HCO
3
-
/ SO
4
2-
)
> 1
ppm
Sulphates (SO
4
2-
)
< 70
ppm
Chlorides (Cl
-
)
< 50
ppm
Free Chlorine
< 0,5
ppm
Phosphates (PO
4
3-
)
< 2
ppm
Ammonia (NH
3
)
< 0,5
ppm
Ammonium Ion (NH
4
+
)
< 2
ppm
Manganese Ion (Mn
2+
)
< 0,05
ppm
Free Carbon Dioxide (CO
2
)
< 5
ppm
Hydrogen Sufide (H
2
S)
< 0,05
ppm
Oxygen Content
< 0,1
ppm
Nitrates (NO
3
-
)
< 100
ppm
Manganese (Mn)
< 0,1
ppm
Iron (Fe)
< 0,2
ppm
Aluminium (Al)
< 0,2
ppm
Caution
If the water circuit is to be drained for a time exceeding one month, the
circuit must be fully charged with nitrogen to prevent any risk of corrosion
by differential venting
