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4.6
Magnesium anodes
The magnesium anode (Mg), also called
"sacrificial" anode, avoids any parasitic currents
that are generated inside the boiler that can
trigger corrosion processes on the device surface.
In fact, magnesium is a metal with a lower
electrochemical potential when compared to the
material that lines the inside of the boiler, therefore
it first attracts the negative charges that form with
the heating of the water and that cause it to
corrode. Therefore, the anode “sacrifices” itself by
corroding instead of the tank. The boiler has two
anodes, one that has been mounted in the lower
part and another in the upper part of the tank (the
area that is most subject to corrosion).
The integrity of the magnesium anodes must be
checked at least every two years (even better if
checked on an annual basis). The operation must
be carried out by qualified personnel.
Before performing the inspection, it is necessary to:
Close the cold water input supply;
Empty the water from the boiler (see
paragraph 8.5);
Unscrew the upper anode and check its state
of corrosion, if more than 30% of the anode
surface is corroded then it is necessary to
replace it;
Carry out the same operation for the lower
anode.
The anodes have appropriate sealing gaskets, in
order to avoid causing water leaks, it is
recommended to use anaerobic sealant for
threads compatible for use on sanitary and
heating systems. The gaskets must be substituted
both in case of inspection as well as the
replacement of anodes with new gaskets.
For the mod. 90
To carry out the verification of the replaceable
anode it is necessary to drain the water from inside
the boiler (see paragraph 4.6).
For the verification or substitution of the sacrificial
anode, remove the lower panel (Fig. 5)
After having removed the lower panel, disconnect
the four electrical connectors of the electronic
control unit. Once removed the panel, unscrew
counterclockwise the anode using an appropriate
instrument and remove the old sealing gasket (Fig.
8).
Verify the integrity level of the component. In case
there are evident, considerable corrosion marks
that could jeopardize its use (reduction of the
diameter, cavity, reduction of the length) carry out
the replacement of the anode taking care of
replacing the sealing gasket as well, both in case
of verification and replacement (Fig. 8).
At the end of the verification or the replacement
of the anode, it is recommended to reset the
water connection (previously removed to allow
the emptying of the boiler) filling and pressurizing
the boiler in order to verify that no water losses are
incurred in the area where the maintenance
intervention has been carried out.
At the end of the verifications, reassemble the
product following backwards the indications
reported in this paragraph.
The operation of periodical verification or
replacement of the magnesium anode is
an opportunity to carry on other little
maintenance operations in order to
ensure the maximum efficiency of the
product.
In particular, once removed the aesthetic
components the evaporator can be
accurately cleaned, using a brush with
soft bristles, taking care not to deform the
aluminum fins. It is also possible to verify
that there are no dirt deposits in the
condensate drain pipe.
These little precautions ensure the total
efficiency of the product with a
consequent energy saving.
