Part number 550-142-950/0122
116
FreeStyle
®
series
2
wall mount gas-fired water boiler – boiler manual
38 Maintenance (continued)
Procedure for chemical cleaning of
DHW circuit
Carefully read and follow the instructions contained in this in-
struction booklet.
Chemical cleaning and maintenance must be carried out by pro-
fessionally qualied personnel, in compliance with the current
Actions For Cleaning Of Heat Exchanger
Water Circuit
y Disconnect the unit from the electrical power supply using
the switch and/or the special cut-o devices.
y Close the valve of Heat exchanger system supply (1) and return
(5) placed before the boiler connections.
y Release the pressure of Heat exchanger circuit by loosen the
plastic screw placed next to the Heat exchanger return (6).
y Disconnect the system piping from Heat exchanger system
supply (1) and Heat exchanger system return (5).
y Tighten the plastic screw placed next to the Heat exchanger
return (6).
y Connect the pipe ttings and hoses for cleaning to the Heat
exchanger system supply (1) and Heat exchanger system re-
turn (5) connections on the bottom of the boiler.
y Fill the pump tank with water and, if necessary, with chemi-
cal conditioners. Use chemical conditioners that are able to
remove from the walls of the pipe of the heat exchanger de-
bris, lime scale, sludge, metal oxides and, in low temperature
systems, also biomass, with just the circulation of the water,
with system hot and/or cold. e products used must not be
corrosive and/or aggressive for metals and plastics and must
not signicantly alter the natural pH of the water.
y e processing time must be chosen according to the amount
of deposits present in the exchanger and however such time
must always be less than the maximum treatment time speci-
ed by the manufacturer on the product data sheet.
y At the end of the cleaning cycle, empty the pump from the
washing water with chemical and recover the product in ap-
propriate containers for disposal.
y Fill the pump with water and perform a washing cycle in order
to remove the chemical conditioner still present within the
coils of the heat exchanger, recovering the liquid in suitable
containers for disposal.
y Disconnect the pipe ttings and hoses of the pump from
the Heat exchanger system delivery (1) and Heat exchanger
system return (5) connections.
y Reconnect the system piping to Heat exchanger system deliv-
ery (1) and Heat exchanger system return (5).
y Open the valve of Heat exchanger system supply (1) and return
(5) placed before the boiler connections.
y Reconnect the unit to the electrical power supply using the
switch and/or the special cut-o devices and turn it ON.
y Purge air from Heat exchanger water system of the boiler
as described in User Manuals for the rst installation of the
boiler.
y Rell to correct pressure the Heat exchanger circuit.
y Check the correct operation of the boiler.
regulations and according to the manufacturer’s instructions.
Do not carry out any operation on the sealed control parts.
Before carrying out any cleaning or maintenance operation,
disconnect the unit from the electrical power supply using the
switch and/or the special cut-o devices.
e disposal of chemicals and residues of chemical cleaning
should be carried out in an appropriate manner, in accordance
with current standards.
In the presence of water harder than 25° Fr (1°F = 10ppm CaCO3),
use suitably treated water in order to avoid possible scaling in
the boiler.
If it is necessary a chemical cleaning of the heat exchanger to
recovery the functionality of domestic hot water production as a
result of prolonged boiler operation with untreated water and / or
very hard water feeding conditions, is allowed the use of products
for the chemical cleaning, if and only if the manufacturer of these
uids provides a guarantee which ensures that its products are
suitable for use and cause no damage to the heat exchanger or
other components and / or materials of the boiler and system.
is procedure is intended as a guideline for a correct restora-
tion of the functionality of domestic hot water production aer
prolonged boiler operation with untreated water and/or very hard
water feeding conditions.
Figure 155 Boiler connections for cleaning domestic water
circuit (Combi Only 80/120 shown)
1 System supply
2 Domestic hot water outlet
3 Gas inlet
4 Cold water inlet
5 System return
6
Pressure relief screw
Before you start, check the compatibility of chemi-
cal cleaning product with the material of the heat
exchanger. e material of domestic hot water
circuit is stainless steel, class AISI 316.
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