Beretta Power Plus Box 1001 EXT, Руководство по установке, Страница: 10 / 40

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b
The space required to reach the safety and
adjustment devices and to carry out maintenance
must be considered. We recommend leaving a space
of at least 500 mm at the back of the appliance.
b
Ensure that the degree of the heating unit’s electrical
protection is compatible with the characteristics of
the installation premises.
b
Electrical parts must be placed at a height of no less
than 500 mm from the ground where heating units are
supplied with fuel gas with specific weight exceeding
that of air.
b
Heating units may not be installed out in the open
(unless they are not specific outdoor units).
b
The heating unit is equipped with a frost protection
function, useful for installations where the temperature
of the environment could be below 0°C. Gas and
electricity must be supplied for this system to work,
apart from a correctly pressurized water circulation
system and the system must not be in shutdown due
to any type of error.
4 .3 System cleaning and water
treatment
It is ABSOLUTELY NECESSARY to treat the water system
for the heating unit to work properly and to guarantee its
service life together with all its components.
This not only applies to jobs carried out on existing
installations but also on new installations.
Sludge, lime-scale and pollutants present in the water can
cause permanent damage to the heating unit, also within
a short time and regardless of the quality standards of the
materials used.
Contact the Technical Assistance Centre for any further
information on type and use of additives.
Chemical-physical characteristics of the water must
conform to the European CSN EN 14868 standard and to
the table given here below:
Initial
filling
water
Regular
service
water (*)
ph 6-8 7,5-9,5
Hardness < 10° < 10° °fH
Electrical
conductivity
< 150 μs/cm
Chlorides < 20 mg/l
Sulphides < 20 mg/l
Nitrides < 20 mg/l
Iron < 0,5 mg/l
(*)
Value of water in circulation system after functioning for
8 weeks.
b
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 conductivity.
b
No controls are required when using de-mineralized
water.
4 .4 General instructions
b
An automatic filling system may not be used for
topping up, which must be done manually and
recorded in the unit handbook.
b
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 distribute the limited quantity of initial
lime-scale.
b
A flushing cycle must be programmed after the plant
has been installed to flush out any installation debris.
b
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 deposits possibly triggering off
under-deposit corrosion.
b
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
b
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.
b
The system must be turned to maximum service
temperature 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 conforms 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 between the material in contact with the impurity
and the surrounding one.
Corrosion from stray currents
Corrosion from stray currents can occur due to the differing
electrical 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.