COSMOGAS MYDENS 60, Инструкция по установке, эксплуатации и обслуживанию

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MYDENS 60
COSMOGAS
5 - INSTALLATION
the winter the leaks on radiator valves are often not visible
because they are dried by the heat produced by the radiator
or boiler). These micro leaks however allow air to enter the
plant. The main points that can give rise to micro leaks are in
the joints and, in particular, from the intake side of the pump
(air vent valves, o-ring seals, loading valves). In these cases,
the plant must be protected with a suitable corrosion inhibitor
in order to prevent damage.
5.6.2 - For correct plant operation it is
necessary to ascertain that:
1) there are no leaks in the plant or the most evident ones
have been eliminated;
2) if an automatic filling system is present, a litre meter must
be installed on order to know the precise size of any leaks;
3) the plant must be filled and topped up with softened water
in order to reduce the total hardness. The water must also be
conditioned in order to maintain the pH within the threshold
envisioned in order to prevent corrosion phenomena;
4) both in new plants and replacements, there must be efficient
systems that eliminate air and impurities: filters, separators of
micro impurities and separators of micro air bubbles;
5) do not drain plant water during routine maintenance, even
if it appears to be an apparently insignificant amount: for
example to clean filters, supply the plant with the relative
cut-off valves upstream and downstream from the filter itself;
6) always analyse the plant water before opening the
communication between the new generator and plant, to
establish whether the chemical and physical features of the
water indicate the necessity to empty the plant completely, the
use of the water already present in the plant or the chemical
washing of the plant, using mains water with the addition of
a detergent, when it is suspected that the plant may be dirty
or particularly clogged and the successive new loading of
treated water.
If the analysis of a sample of water that will be used to load
the plant shows the following factors:
- 9.6 < pH < 10.5 (if the plant is in contact with aluminium, the
pH must be lower than 8.5)
- Ca++ + Mg++ : <0.5°f
- OH + 1/2 C03 : from 5 to 15°f
- P205: from 10 to 30 mg/l
- Na 2S03: from 20 to 50 mg/l loading can be continued. A
inhibitor must be used if the features are different.
5.6 - Water supply
Have the water network connection pressure checked. If
necessary, have a suitable pressure reducer installed.
ATTENTION !!! The central heating plant (and
therefore the heat module) must be connected to the
water mains with the interposition of a device that
prevents backflow of drinking water towards the plant,
as requested by the current Anti-pollution Safety
Standards.
5.6.1 - Recommendations of the features
of the water inside the plant
Filling the central heating plant is an extremely delicate
operation, not to be underestimated, regarding replacement
of the heat generator or new installations. In certain cases, the
incorrect assessment of the plant water features can lead to
damage of the plant and heat module. A plant is almost never
sealed perfectly; sometimes water leaks as well as the entry of
oxygen can occur. Both of these phenomena are dangerous.
The main parameters that can negatively affect the lifespan
of the plant are:
- The simultaneous presence of different metals (copper,
brass, steel and aluminium) which, in aqueous environments,
give rise to galvanic corrosion.
- The presence of free oxygen, due to the infiltrations of air
that occur in proximity of fittings and gaskets, constitutes a
typical corrosive agent, particularly active at temperatures
between 50 and 70° C.
- The loss of water, which leads to frequent top-ups, can act in
a corrosive manner and as a deposit, depending on the type
of water available to top-up the same.
In all cases, the size of the leaks (and relative top-ups) must
be kept under control, especially when an automatic filling
system is installed. In this case, the installation of a meter is
highly recommended, which indicates the amount of water
reintegrated.
Natural impurities or added in the water. Many drinking waters
can contain high concentrations of chlorides and sulphates,
which can increase the speed of corrosion on metal surfaces.
Other undesired components could have been introduced into
the plant before or during installation (construction materials,
metal shavings, sawdust, grease, deposits and dirt in general).
Welding residues can also cause corrosion, both in the case of
new plants and in the case of modifications or repairs. In the
old plants designed to operate with radiators, characterised
by a very large piping diameter, the water content in the
plant is noteworthy and promotes the formation of sludge
and deposits.
Sludge and Deposits The presence of black deposits
(magnetite) indicate that corrosion is limited; however, the
high specific weight of this oxide can cause difficult to remove
clogging, especially in the hottest areas. The deposits are
due to the hardness of the water, i.e. the presence of calcium
and magnesium salts. The calcium goes to the hottest areas
of the plant in the form of carbonate. The magnetite often
contributes to strengthening the deposit. The iron oxide (the
water is a reddish colour) is a sign of corrosion by oxygen.
Frequent leaks In the event of frequent leaks, hydrogen and/
or air accumulate on the top part of the heat exchanger and
the radiators, preventing complete heat exchange.
When the electrolytic corrosion process starts, the level of the
water in the plant drops and gases accumulate on the top part
of the heat exchanger and on the radiators. The presence of
air is caused by the fact that the plant may not be perfectly
sealed. A slow drop in plant pressure due to a leak is often
difficult to find, especially when the flaw is very small (in