C0210101-07-16-EN
23
Check that the water contained in the hydraulic circuit respects the following characteristics for the whole lifetime of the system:
Description
Symbol
Value
1
Concentration of hydrogen ions
pH
7.5
9
2
Presence of calcium (Ca) and magnesium (Mg)
Hardness
4
8.5 °D
3
Chloride ions
Cl
-
< 150 ppm
4
Iron ions
Fe
3+
< 0.5 ppm
5
Manganese ions
Mn
2+
< 0.05 ppm
6
Carbon dioxide
CO
2
< 10 ppm
7
Hydrogen sulphide
H
2
S
< 50 ppb
8
Oxygen
O
2
< 0.1 ppm
9
Chlorine
Cl
2
< 0.5 ppm
10
Ammonia
NH
3
< 0.5 ppm
11
ratio between carbonates and sulphates
HCO
3-
/ SO
4
2-
> 1
Tab.4
where:
1/1.78 °D=1 °Fr with 1°Fr= 10 gr CaCO
3
/ m
3
ppm = parts per million;
ppb = parts per billion
Explanatory notes
ref. 1:
A greater concentration of hydrogen ions (pH) than 9 implies a high risk of deposits, whereas a lower pH than 7 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:
The concentration of chloride ions with higher values 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:
Usually 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.
In the case of service fluids other than water (e.g. ethylene or propylene glycol), it is advisable to always use fluids containing 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
refrigeration system heat exchangers.
5.1 Evaporator / recuperator
The following must be installed on the heat exchanger hydraulic circuit taking care to respect the correct positioning (See fig. 1 page A1):
Two pressure gauges with a suitable range (inlet - outlet).
Two service cocks for the pressure gauges.
Air bleed valves to be fitted to the highest points of the circuit.
Two vibration damping joints (inlet - outlet) positioned horizontally.
One flow switch to be fitted at the unit outlet in a linear stretch of a length of about 7 times the diameter of the pipe itself. The flow switch must
be calibrated so as to guarantee a minimum water flow to the heat exchangers, not less than the value indicated in the unit bulletin or declared
by the supplier. If this value is not available, calibrate the flow switch to 70% of the rated water flow of the unit (not envisaged for
desuperheaters).
A calibration valve at the outlet.
Two shut-off valves (inlet - outlet).
A manual bypass valve to be used upon start-up when the temperature of the water is too cold/hot
A mechanical filter with a maximum mesh size of 1 mm to be fitted as near as possible (maximum distance 2 metres) to the heat exchanger
inlet
A drain cock to be fitted in the lowest point of the hydraulic system.
A circulation pump.
All other equipment listed in fig. 1 page A1
It is also important that there is no air in the water circuit and no sudden variations in pressure or any points below atmospheric pressure.
There must not be any sudden variations in the flow of water. When the machine is running, there must not be variations in the flow of water of
more than 10% a minute: for this reason it is advisable to install an independent pump unit for each single evaporator with a circuit separate
from the rest of the system.
For the production of domestic water it is recommended to install an intermediate exchanger to prevent dirt, corrosion and pollution of the water
from any oxides.
Type Q and type R multi-purpose machines are for 4 pipe systems whose hydraulic circuits must always be able to have circulating water.
The directions for installation set out above represent a necessary condition for the validity of the guarantee.
However, Climaveneta is
willing to examine any different needs, which must in any case be approved before the refrigeration system is started up.
