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4.4.4
Water quality
OBLIGATION:
The values shown in the table must be guaranteed during the entire life cycle of the machine.
Ref.
1
Presence of calcium (Ca) and magnesium
2
3
4
5
6
7
8
9
10
11
Ratio between carbonates and sulphates
12
13
where: 1/1.78°D = 1°Fr with 1°Fr = 10 gr CaCO
ppm = parts for millions
ppb = parts per billion
Explanatory notes:
ref. 1:
Concentrations of hydrogen ions greater than those indicated implies a high risk of deposits, whereas
concentrations of hydrogen ions lower than those indicated implies a high risk of corrosion;
ref. 2:
The hardness measures the amount of Ca and Mg carbonate dissolved in the water with a temperature
lower than 100°C (temporary hardness). A high hardness implies a high risk of deposits;
ref. 3:
Concentrations of chloride ions higher than those indicated causes corrosion;
ref. 4 - 5 - 8:
the presence of iron and manganese ions and oxygen leads to corrosion;
ref. 6 - 7:
carbon dioxide and hydrogen sulphide are impurities that promote corrosion;
ref. 9:
In water from the waterworks it is a value of between 0.2 and 0.3 ppm. High values cause corrosion;
ref. 10:
The presence of ammonia reinforces the oxidising power of oxygen
ref. 11:
Below the value shown in the table, there is a risk of corrosion due to the trigger of galvanic currents
between copper and other less noble metals.
ref. 12:
the presence of sulphate ions leads to corrosion;
ref. 13:
the presence of phosphate ions leads to corrosion.
Checks should be carried out on a regular basis, taking samples at various points of the hydraulic system.
During the first year of operation, it is recommended to perform checks every 4 months. Checks can then be performed once every
six months as from the second year of operation.
OBLIGATION:
Parameter values outside the indicated ranges may lead to the formation of deposits and scale, and/or
encourage the occurrence of corrosive phenomena inside the system. In case of service fluids other
than water (e.g. ethylene or propylene glycol), it is advisable to always use special inhibitors that offer
thermal stability within the operating temperature ranges and protection against corrosion
phenomena.
It is absolutely essential that, in the presence of dirty and/or aggressive water, an intermediate heat
exchanger is placed upstream of the heat exchangers.
4.4.5
Anti-freeze solutions
•
Protect the water circuit with an anti-freeze mixture when the ambient temperature may fall below freezing, or when the
operating temperature of the carrier fluid is below 5°C.
If the use of products other than mixtures of water and ethylene or propylene glycol is envisaged, contact the manufacturer's
technical office to check compatibility with the components of the machine.
Installation, use and maintenance manual
Description
Hydrogen ions
(Mg)
Chloride ions
Iron ions
Manganese ions
Carbon dioxide
Hydrogen sulphide
Oxygen
Chlorine
Ammonia NH
3
Sulphate ions
Phosphate ions
3
/ m
3
Symbol
Range values
pH
7.5 - 9
Hardness
4 ÷ 8.5 °D
-
Cl
< 150 ppm
3+
Fe
< 0.5 ppm
2+
Mn
< 0.05 ppm
CO
< 10 ppm
2
H
S
< 50 ppb
2
O
< 0.1 ppm
2
Cl
< 0.5 ppm
2
NH
< 0.5 ppm
3
2-
HCO
-/SO
3
4
--
SO
< 100 ppm
4
3-
PO
< 2.0 ppm
4
> 1
25
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