95
cod. 3541T630 - Rev. 03 - 05/2020
EN
DORA
200 HT - 260 HT
ATTENTION!: Intervention of the safety thermo-
stat can be caused by a fault linked to the control
board or by no water inside the tank.
ATTENTION!: Carrying out repair work on parts
with safety function compromises safe opera-
tion of the equipment. Replace faulty parts with
original spare parts only.
NB!: Intervention of the thermostat excludes operation of
the heating element but not the heat pump system within
the permitted operating limits.
ATTENTION! If the operator is unable to elimi-
nate the fault, switch off the equipment and con-
tact the Technical Assistance Service, communi-
cating the model of the product purchased.
9. MAINTENANCE
ATTENTION!: Any repairs to the equipment must
be carried out by qualified personnel. Improper
repairs can put the user in serious danger. If your
equipment needs any repair, contact the service
center.
ATTENTION!: Before undertaking any mainte-
nance operation make sure the equipment is not
and cannot accidentally be electrically powered.
Therefore, disconnect the power at every main-
tenance or cleaning operation.
9.1
Sacrificial anode check/replacement
The magnesium (Mg) anode, also called "sacrificial" anode, pre-
vents any eddy currents generated inside the boiler from trig-
gering surface corrosion processes.
In fact, magnesium is a weakly charged metal compared to the
material of which the inside of the boiler is coated, therefore it
attracts first the negative charges that form with the heating of
water, consuming itself. The anode therefore "sacrifices" itself
by corroding itself instead of the tank. The boiler has two an-
odes, one fitted in the lower part of the tank and one fitted in the
upper part of the tank (area more subject to corrosion).
The integrity of the Mg anodes must be checked at least every
two years (preferably once a year). The operation must be per-
formed by qualified personnel.
Before doing the check:
•
Close the cold water inlet.
•
Proceed with emptying the boiler (see par. “9.2 Boiler empty-
ing”).
•
Unscrew the upper anode and check its corrosion; if the cor-
rosion affects more than 2/3 of the anode surface proceed
with replacement.
fig. 43
The anodes have a special sealing gasket, to prevent water
leaks; it is advisable to use anaerobic thread sealant compat-
ible for use in heating-plumbing systems. The gaskets must be
replaced with new ones in case of checking and also anode
replacement.
9.2 Boiler emptying
If not in use, especially in case of low temperatures, it is advis-
able to drain the water inside the boiler. For the equipment in
question, just open the drain cock as per the example hydraulic
connections chap. “Plumbing connections” on page 77 (see
fig. 16).
NB!: In case of low temperatures, remember to empty the
system to avoid freezing.
