INSTRUCTIONS FOR THE FIRST TIME IN SERVICE
RK 100 - RAD - ING - MAN.INST - 1311.1 - DIGITECH CS MIAH4
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4.3.2 System water features
To ensure that the appliance functions correctly, the following fundamental rules must be observed:
1. make sure that the system doesn’t present any leaks and that the bigger ones or the most evident are
removed;
2. In presence of an automatic filling system, a liter counter must be installed to know precisely the leaks
entity.
3. Softened water must be used to fill up the system in order to reduce the total hardness. The water must be
also conditioned to maintain the pH value within the standard limit to avoid corrosion phenomena.
4. In case of new boilers or boiler replacement, the system must be equipped of efficient devices which
provide the boiler against air and impurities: Y filters, micro impurities and micro air-bubbles’ separators;
5. Make sure that the system water is not discharged during the current maintenance operations even if
quantities are apparently insignificant: for example the system must be equipped with apposite shut-off
valves for the filters’ cleaning.
6. Prior to connect a new boiler to the system, always proceed with the system water analysis to check if
water parameters indicate the necessity to drain the system, to use the water already present in the system
or to proceed with a chemical system flushing by using the running water with the addition of a detergent in
case the system is particularly dirty or obstructed, and to consequently fill up the system with new treated
water.
Water treatment
In order to preserve the primary heat exchanger’s integrity and always guarantee optimal thermal exchanges, the
mains supply water to the primary circuit, circulating inside the condensing boiler heat exchanger, must present
long-term definite and constant features.Following preparation and maintenance operations, in compliance with the
current standard UNI-CTI 8065, are fundamental:
• flushing up the system;
• check the system water features;
The choice of the water treatment type must be made according to the water features, the system type and
the pureness limit requested.
Oxygen
A certain quantity of Oxygen always enters in the system, both in the phase of filling and during the system use, in
case of water recovery or in presence of hydraulic components without barriers to the oxygen. Oxygen by reacting
with the steel creates corrosion and muds formation. While the primary heat exchanger is made of stainless steel,
which is not subjected to corrosion, muds created inside the carbon steel system will deposit in warm parts
included the primary heat exchanger. The result will be the reduction of the boiler capacity and the obstruction of
the primary heat exchanger’s active parts by provoking damages to the boiler.
Precautions to limit this phenomenon are:
- Mechanical systems: a combined air vent and a deslimer correclty installed reduce the Oxygen quantity circulating
in the system.
- Chemical systems: additives allow the Oxygen to remain dissolved in the water.
Hardness
The hardness of the filling or recovery water brings a certain quantity of calcium in the system. Calcium adheres on
warm parts included the primary heat exchanger. The result is the reduction of the boiler capacity and the
obstruction of the primary heat exchanger’s active parts by provoking damages to the boiler.
In case the filling or recovery water of the system is not within the values reported here below, it must be
sweetened. Additional additives can be used to keep Calcium in solution. The water hardness must be controlled
and registered regularly.
A chemical treatment is necessary if the limit of values above is exceeded.
The choice of the water treatment type must be made according to the water features, the system type and
the pureness limit requested.
Acidity
6,6 < pH < 8,5
Conductivity <
400
μ
S/cm (a 25°C)
Chlorides <
125
mg/l
Iron <
0,5
mg/l
Copper <
0,1
mg/l
