14
1
- Good corrosion resistance.
2
- If different factors of this type are present, corrosion can occur.
3 - Use not recommended.
4.3.3
Protection against freezing
If you do not wish to drain the system during periods where the machine is not used, the water
may freeze, or if the system must operate with temperatures less than 5°C, ethylene glycol must
be mixed with the water.
Adding glycol changes the physical characteristics of the water and the performance of the
machine.
The table indicates the multiplicative factors to calculate the performance change based on the
percentage of glycol used.
% G
10
20
30
40
50
Tc
-4.5
-9.5
-15.5
-21.5
-32.5
CQ
0.975
0.953
0.931
0.914
0.882
CP
0.998
0.995
0.99
0.985
0.975
CG
1.01
1.04
1.08
1.14
1.2
CP
1.05
1.13
1.21
1.26
1.32
% G = Glycol percentage
Tc = Water freezing temperature (°C)
CQ = Cooling capacity correction factor
CP = Electrical power absorbed correction factor
CG = Water flow correction factor
Cp = Pressure drops correction factor
4.4
Connection to the system
4.4.1
Models without hydronic kit
A: Condenser connections (user side);
B: Evaporator connections (source side);
In these models, the connections are positioned outside the unit.
•
Remove the protection caps from the connections.
•
Connect the pipes to the connections.
All exchangers that can be connected directly are equipped with grooved connections. The units
are all supplied with tubes with grooved connection on one side and welding connections on the
external side, together with the relevant connecting clamp and gasket. These allows the installer
to make the most appropriate connection. By welding, in fact, it is possible to connect a threaded
or flanged sleeve or even a grooved sleeve for a grooved connection.
Provide shut-off valves and anti-vibration joints on the connection pipes.
During the hydraulic connection operations, never operate with free flames near or inside
the unit.
4.5
PV3E evaporation control
On the source side there is a limit on the inlet temperature of 45 ° C.
If there are applications in which it is necessary to enter with water at a higher temperature, it is
necessary to adopt an evaporation control by means of a 3-Way valve following the diagram
shown below.
The proposed scheme must be respected to allow the maintenance of the flow rate to the
exchanger (Evaporator), it also allows the control of the inlet temperature of the evaporator by
injecting cold water.
The analogue control signal comes directly from the unit control.
If the 3-way valve is not supplied, bear in mind that the control signal is only and exclusively 0-
10V (IVE option).
The servomotor, therefore, must necessarily be able to be controlled by this signal.
The valve is supplied, but the installation must be carried out on site following the
principle diagram shown.
The valve must be installed near the unit.
Content
Concentration mg/l or ppm
Material
Electrical conductivity
μS/cm
<10
1
2
10-500
1
1
>500
1
2
Ammonium
NH4
<2
1
1
2-20
1
2
>20
1
3
Free chlorine
Cl2
<1
1
1
1-5
3
1
>5
3
3
Hydrogen Sulphide
H2S
<0.05
1
1
>0.05
1
3
Free Carbon Dioxide
CO2
<5
1
1
5-20
1
2
>20
1
3
Nitrate
NO3
<100
1
1
>100
1
2
Iron
Fe
<0.2
1
1
>0.2
1
2
Aluminium
AL
<0.2
1
1
>0.2
1
2
Manganese
MN
<0.1
1
1
>0.1
1
2
