8
INSTALLATION
4.3
Water connections
Condexa Pro2 EVO thermal modules are made up of 2, 3 or 4
thermal elements which are common to all the boilers belong-
ing to the same family and they have a thermal power of 75 kW .
Each thermal module is equipped with the following connec-
tions which have been pre-set for the connection to the system
(see table).
MANIFOLD
DIMENSION
REMARKS
CONNECTION
TYPE
upper water
manifold
2” 1/2
system inlet
Flanged man-
ifolds for an
easy connec-
tion to the
system
lower water
manifold
2” 1/2”
system outlet
gas manifold 2”
the gas inlet can
be connected
simultaneously to
the two ends of
the boiler
condensate
manifold
50 mm
connect to sewer
system
see “4.6 Up-
grading existing
systems”
Socked ends
manifolds for
an easy real-
ization of the
flue system
using plastic
pipes (PP).
flue pipe
(singol unit) 160 mm
see “4.8 Position-
ing and prepara-
tion for installa-
tion”
4.4
System cleaning and water treatment
This preventive measure is absolutely required whenever a heat
generator needs to be replaced in but it is in any case recom-
mended also on new systems, in order to remove any waste,
dirt, working residues, etc.
To clean the system, if the old generator is still present in the
system:
− add a descaling additive to the system water (contact the
R
Technical Assistance Service);
− Have the system operate with the generator ON for ap-
proximately 7 days;
− Discharge the system’s dirty water and wash the system
once or several times using clean water.
If the system is very dirty, repeat the last procedure one more
time.
If the old generator is not present or available, use a pump to
circulate the water + additive through the system for about 10
days and perform a final washing as described in the previous
paragraph.
At the end of cleaning operations, before installing boiler
Condexa Pro2 EVO
, it is advisable to add protection) to the sys-
tem water (contact the
R
Technical Assistance Service);
9
Where softened water is used it is compulsory to re-check
conformity to tolerances for water in regular service after 8
weeks from topping up and in particular the electrical con-
ductivity.
9
No controls are required when using de-mineralized water.
4.4.1
General instructions
9
An automatic filling system may not be used for topping
up, which must be done manually and recorded in the unit
handbook.
9
If there are more than one boiler, they must all be put into
service either contemporarily or with a very low rotation
time during the initial period of service, so as to evenly dis-
tribute the limited quantity of initial lime-scale.
9
A flushing cycle must be programmed after the plant has
been installed to flush out any installation debris.
9
Water used for filling or for eventually topping up the system
must always be filtered (synthetic or metal mesh filters with
filtering capacity of no less than 50 micron) to avoid depos-
its possibly triggering off under-deposit corrosion.
9
The heating system must be flushed out and cleaned with
good workmanship before filling up the existing systems.
The boiler may not be filled until after the heating system
has been flushed out.
4.5
New heating systems
9
The system must be filled up slowly the first time; once it is
filled and the air expelled it should never need to be topped
up again.
9
The system must be turned to maximum service tempera-
ture during the initial ignition to facilitate deaeration (a too
low temperature prevents the gas from coming out).
4.6
Upgrading existing systems
Where the boiler has to be replaced it is not recommended to fill
up again if the quality of the water in the existing systems con-
forms to specifications. If the quality of water fails to conform to
specifications, we recommend either re-treating it or separating
the systems (the water quality requirements must be respected
in the boiler system).
4.7
Corrosion
Under-deposit corrosion
Under-deposit corrosion is an electrochemical process, due to
the presence of sand, rust, etc., inside the mass of water. These
solid substances generally deposit on the bottom of the boiler
(sludge), on tube and pipe heads or in the gaps between pipes
and tubes.
Micro-corrosion phenomena may be triggered off owing to the
difference in electrochemical potential coming to be created be-
tween the material in contact with the impurity and the sur-
rounding one.
Corrosion from stray currents
Corrosion from stray currents can occur due to the differing elec-
trical potentials between water in the boiler and the metallic
mass of the boiler or piping. This process leaves unmistakeable
traces i.e. small regular conical holes.
9
It is advisable to connect up the various metal parts to a
good earthing system.
9
The systems must always be separated if oxygen is either
continuously or occasionally introduced into the installa-
tions (e.g. floor heating without pipes in synthetic material
resistant to diffusion, open vessel systems, frequent topping
up).
From what we have seen it is therefore important to avoid two
factors possibly leading to the above mentioned processes i.e.
contact between air and water in the installation and regular
topping up with fresh water.
To eliminate contact between air and water (and to prevent the
