Italtherm CITY MAX 26 K manual 

IMPORTANT! Install the gasket
included in the documents bag,
on the inlet/outlet ange, as
shown on page 21.
Instruction
Handbook for:
use
adjustment
maintenance
installation
CITY MAX
32 K
26 K

Green Heating Technology
2
Table of Content
Safety warnings
Safety warnings symbols legend .............. 4
References to Laws and Norms ............... 4
Personnel in charge of installaon ............... 4
Installaon, use and maintenance ............... 4
User warnings ............................ 5
Important . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
First starng up and Use ....................... 5
Installaon, rst starng up, maintenance and
servicing ................................. 6
Appliance booklet or central plant booklet ........ 6
Combuson checking ......................... 6
Boiler operaon and servicing .................. 6
User guide
The front control panel ..................... 7
Commands on the lower side ................ 8
Commands outside the boiler ............... 8
Typical use ............................... 9
Preliminary operaons ........................ 9
Boiler acvaon .............................. 9
Temperature adjustment ...................... 10
An-Legionella funcon ................... 10
Incidental malfunconing .................. 11
The burner doesn’t turn on .................... 11
Shortage of domesc hot water producon ...... 11
Boiler inacvity .......................... 11
Safety shut o .............................. 11
Stand-by mode with an-frost & an-locking
funcon ................................. 12
“Ambient An-Frost” Funcon ................. 13
Installaon
Law and regulaon prescripons for the
installer .............................. 13
Dimensions and connecons ............... 14
Pump capacity diagrams ................... 14
Warnings for the installaon of oponal kits or
special systems ........................ 15
Floor heang system . . . . . . . . . . . . . . . . . . . . . . . . . 15
Specicaons for inlet air .................. 15
Domesc water supply characteriscs ........ 15
Protecon against freezing ................. 15
Siphon overow drain ..................... 16
Outdoor installaon in a parally protected
place ................................ 16
Posioning and fastening .................. 16
Hydraulic system (DHW and heang) ......... 18
Advices and suggesons to avoid vibraons and noises
in the system ............................ 18
Cleaning and preservaon of the systems ........ 18
Heang system .............................. 18
Condense drain .......................... 18
System lling and pressuring ............... 19
DHW storage tank lling ...................... 19
Heang system lling ......................... 19
Gas connecon .......................... 20
Electrical connecons ..................... 21
Flue systems ............................. 21
Installaon of the ue inlet/outlet ange gasket .. 21
General indicaons .......................... 22
Dimensioning the inlet and outlet ducts ......... 23
Flue system types ............................ 24
Examples of installaon of inlet and outlet ducts .. 25
Adjustment and Maintenance
First starng up .......................... 26
Maintenance operaons ................... 27
Access to the inside of the boiler ............ 28
Venng the primary exchanger ............. 29
Venng the storage coil .................... 29
Combuson group cleaning ................ 30
Combuson test and adjustment ............ 31
Max heang power adjustment ............. 33
Power input / display / fan rpm table ........ 34
Electronic sengs ........................ 35
Accessing the main board ..................... 35
Main board sengs .......................... 35
Gas conversion ........................... 36
Hydraulic sengs (pump speed) ............ 38
Draining the heang system and the storage
coil .................................. 38
Draining the storage unit ................... 38
Alarms - boiler block ...................... 39
Warnings for servicing ..................... 44
Technical data ............................ 45
Boiler internal components ................ 48
Electrical diagram ........................ 49
Hydraulic diagram ........................ 50
Addendum
Outdoor Sensor Kit ....................... 51
Installaon and seng ....................... 51
Outdoor Sensor kit and Remote Control ......... 51
Remote Control Kit ....................... 52

Green Heating Technology
3
Safety warnings
This instrucons manual is an essenal and complementary part of the product and it is supplied to-
gether with the boiler.
Carefully read the manual, achieving all important informaon for a safe installaon, use and
servicing.
fCarefully keep the manual, together with the documentaon of all the accessories of the boiler and
of the system, for any further consultaon you may need.
fThe installaon must be carried out by a qualied technician, in accordance with manufacturer in-
strucons and with the relevant requirements of the current issue.
fCarbon monoxide (CO) danger: the CO is a no-smelling and no-colour gas. When a forced draught
boiler with air inlet from the room (appliance type B2) is installed, permanent venlaon of the
installaon room is mandatory and extremely important. Venlaon must be made and sized in
compliance with Laws and Rules in force. Whatever manumission, closing or neutralizaon of the
permanent venlaon could lead to very serious consequences to people in the rooms, as intoxica-
on by CO, permanent damage and death. Besides, the CO and O2mix can be explosive.
fA qualied technician is a person with a specic technical competence in the eld of the heang
appliances for domesc use and domesc hot water producon, in compliance with Laws and Rules
in force.
fThe operaons that the user can do are only and exclusively the ones contained in the "USER GUIDE"
secon.
fThe manufacturer has no contractual and extra-contractual responsibility for any damage arising
from wrong installaon, wrong use and non-observance of current laws and instrucons given by
the manufacturer himself.
fImportant: this gas boiler is used to heat the water at a temperature lower than the boiling one, at
atmospheric pressure; it must be connected to an heang system and/or to a domesc hot water
system, in accordance with its features and power.
fPacking items (cartons, nails, plasc bags and so on) must not be le within children easy reach, as
they are potenally dangerous.
fBefore any cleaning or servicing operaon, disconnect the boiler from the mains electrical supply by
means of the main electrical switch and stop the gas supply by means of the suitable cock.
fIn case of fault and/or bad operaon of the appliance, disconnect it immediately and do not try to
repair it by yourselves.
fBoiler servicing and repair must be carried out exclusively by qualied technicians, which will use
original spare parts. Strictly observe the above requirement, avoiding any risk of compromising the
appliance safety.
fIf the appliance should be denively dismissed, remove or cut o any potenal dangerous item.
fWhen transferring the appliance (e.g. leaving it installed aer a removal or a sale of the building),
make always sure that the instrucons manual is close to the boiler for the future use of new owners
and/or installers.
fThis appliance must be used for its clearly recommended ulizaon only. Any other ulizaon must
be considered dangerous and incorrect.
fIt is strictly forbidden to use the appliance for dierent purposes than the specied ones.
fThis appliance must be installed exclusively to wall.

Green Heating Technology
4
Safety warnings symbols legend
Generic safety
warning
Electrical danger
(fulguraon)
Physical danger
(personal damage)
Thermal danger
(burns)
General warning or advice to avoid material damage
or to achieve improvements
References to Laws and Norms
All the references to norms and naonal laws menoned in this handbook are indicave as
laws and norms are subject to issues and integraons by the authories in charge. Also comply
to eventual local norms and laws (not menoned in this handbook) in force in the territory
where the installaon takes place.
Personnel in charge of installaon
Place here all necessary advices according to naonal rules about WORK SAFETY of Personnel in charge
of installaon. An example follows:
Law number 192 of 19-August-2005 and further revisions “Title of the law or brief descripon”.
Always proceed with cauon when handling the boiler and carrying out installaon/mainte-
nance work as metal parts may cause injuries such as cuts and abrasions. Wear personal protec-
on devices (especially gloves) while doing the above menoned operaons
Installaon, use and maintenance
Place here all necessary advices according to naonal rules about BOILER INSTALLATION, An example
follows.
Law number 412 of 26-July-1993 n°412 and further revisions “Title of the law or brief descripon”.

Green Heating Technology
5
User warnings
Important
In case of gas smell:
1 - do not press electrical switches, use the telephone or other objects that can provoke
sparks;
2 - open immediately the windows and the doors in order to cleanse the room air;
3 - close the gas supply taps;
4 - call a qualied technician.
Do not obstruct the venlaon openings of the gas boiler room, in order to avoid possible
dangerous situaons as the creaon of poisonous or explosive mixtures.
First starng up and Use
The rst starng up and the maintenance of the boiler must be performed by a professionally
qualied sta (for example the installer or the Service Centres authorized by ITALTHERM)
The laer will check that:
fthe label technical data of the gas boiler correspond to those of the gas available;
fthe main burner regulaon is compable with the gas boiler output;
fthe chimney works correctly, expelling the combuson products;
fthe air supply and the combuson products evacuaon work correctly, in accordance with the re-
quirements in force;
fthe condions for a correct venlaon are guaranteed, also when the gas boiler is located inside a
closed space (with suitable caracteriscs).
This boiler is designed and prepared to be supplied with Natural Gas G20 (Methane) or Com-
mercial Propane G31. A qualied technician can convert it to operate with one of these two
types of gas above said. It must never be used with butane gas G30 (that can be present, pure
or mixed with Propane G31, in the portable gas boles for cookers).
The User must not touch sealed items nor break the seals. Only specialized technicians and the
ocial technical service can break the seals of sealed items.
The boiler is ed with safety devices that block operaon the case of problems with the boiler
or related systems. These devices must never be disabled: if a device intervenes frequently,
have a qualied technician located the cause, even in systems to which the boiler is connected,
and in the ue inlet/outlet system that must be ecient and made according to the laws in force
(see examples in paragraph "Flue systems" on page 21). If a boiler component has failed, you must
only use original replacement parts
When the boiler is o for a long period see the Paragraph "Boiler inacvity" on page 11 for the
necessary precauons about the electrical supply, the gas supply and the protecon against
freezing.
Do not touch the heated surfaces of the boiler, as the doors, the ue, the chimney pipe, etc.,
also aer the boiler operaon because, for a certain me, these surfaces are overheated. Any
contact with them can cause dangerous scalds. It is then forbidden to let children or inexperi-
enced people be close to the boiler, during its operaon.

Green Heating Technology
6
fDo not expose the wall hung gas boiler to water or other liquids sprinklings, or to vapours directly
coming from gas cookers/hobs.
fDo not obstruct the air inlet or ue outlet terminals, even momentarily or parally.
fDo not put any object on the gas boiler and don't leave any ammable liquid or solid materials, (e.g.
paper, clothes, plasc, polysrene) in its proximity.
fThis appliance is not intended for use by persons (including children) with reduced physical, sensory
or mental capabilies, or lack of experience and knowledge, unless they have been given supervi-
sion or instrucon concerning use of the appliance by a person responsible for their safety. Children
should be supervised to ensure that they do not play with the appliance. (CEI EN 60335-1:2008-07 § 7.12)
fIf the gas boiler is going to be denively unused, call a qualied technician to carry out all required
operaons, checking in parcular disconnecon of gas, water and electrical supplies.
fOnly for those models that draw directly from the installaon room (type B appliances installed in-
door): the installaon of aspirators, replaces or similar appliances in the room where the type B ap-
pliance is installed (and in adjacent rooms in case of indirect venlaon) is prohibited except in cases
foreseen by rules in force and anyway the installaon must be made in compliance with all specic
safety measures menoned in the rules and laws in force, even in case of modicaons or addions.
Installaon, rst starng up, maintenance and servicing
All operaons for installaon, rst starng up, maintenance, servicing and gas conversion must be car-
ried out by qualied technicians, in accordance with the Norms and Laws in force.
Maintenance operaons must be carried out in compliance with the manufacturer prescripons, and in
compliance with the laws and rules presently in force for what is not menoned in this handbook; we
advice to perform them at least once a year to maintain the boiler’s performance.
Appliance booklet or central plant booklet
All appliances must have an appliance booklet (for outputs less or equal 35 kW) or a central plant book-
let (for outputs more than 35 kW). All maintenance and servicing operaons and combuson checks
must be wrien on the booklet, together with the name of the person responsible for servicing.
Combuson checking
Combuson checking consists of a control of the boiler eciency. Boilers that, aer the checking, will
have eciency rates lower than the ones required and not changeable with suitable adjustments (that
must be performed by qualied technicians), must be replaced.
Boiler operaon and servicing
The user (owner or tenant of the at where the boiler is installed) or the administrator of the block of
ats (in case of a central heang system) are responsible for the appliance operaon and servicing; they
can both transfer the responsibility of the servicing and eventually of the operaon to another person,
which must be a qualied technician as indicated by the Laws. Even if the user or the administrator de-
cide to assume personally this responsibility, ordinary servicing of the warm air heater and combuson
checks must be anyway carried out by a qualied technician

Green Heating Technology
7
User guide
The front control panel
1
green
Electrical Supply Indicator Light
O - boiler not electrically supplied.
Blinking - boiler electrically supplied, but not acve because the knob 12 is on .
On - boler acve. Knob 12 on , or on along the scale .
Flashing with short pulses - actuated for mistake, by the user, a funcon reserved to
the technician. Rotate immediately the knob 13 back on the scale .
2
yellow
Burner Indicator Light
O - the ame in the burner is o.
On - the ame in the burner is on.
3
red
Alarm Indicator Light
O - no problems detected.
Blinking or Flashing - see "Alarms - boiler block" on page 39.
Flashing with short ashes - the user has acvated, by mistake, a funcon reserved to
the technician. Turn the knob 13 on the scale immediately.
4service Indicaon, on the display, for the Technician, usually not displayed.
52-digit
number
on the
display
Normally it indicates, in °C, the measured temperature of the heang system ow or
of the DHW storage (when the relevant symbol 6 or 7 ashes).
During the adjustment of the heang system temperature (rotang the knob 12 along
the scale ) or domesc hot water (rotang the knob 13 along the scale ) it
shows the set value, in °C.
When the knob 13 is turned on 17, it is displayed "– –".
6
-
on the
display
Usually, they are shown in xed mode and they indicate that the boiler is ready to
supply heat to the relevant heang or DHW . When the boiler is in Summer
mode , the symbol is not shown.
They blink during the actual heat delivery, by the boiler, to the relevant system.
7
s
e
r
v
i
c
e
service
8
9
10
12 13
14
15
17
16
11
3
4
67
5
1
2
00056 00

Green Heating Technology
8
8Posion on which the knob 12 should be posioned to turn the boiler o or to reset
a boiler block.
9Posion on which the knob 12 should be posioned to acvate the boiler in Winter
mode (both Heang and Domesc Hot Water funcons available) (aenon: only if the
Remote Control Kit is not installed).
10 Scale on which the knob 12 should be posioned to adjust the Heang system tem-
perature (aenon: only if the Remote Control Kit is not installed).
11 Posion on which the knob 12 should be posioned to acvate the boiler in Summer
mode (only Domesc Hot Water funcon available and exclusion of Heang)
12 boiler
mode Knob that allows to switch the boiler in OFF mode 8, Summer 11 or Win-
ter 9 and to adjust the Heang system temperature 10.
If the Outdoor Sensor Kit is installed, see "Outdoor Sensor Kit" on page 51.
If the Remote Control Kit is installed, see "Remote Control Kit" on page 52.
13 DHW Knob that allows to adjust the temperature of the water in the storage (along the
scale 14 ). The use of the posions 15 and 16 is reserved to the technician.
14 Scale on which the knob 13 should be posioned to adjust the Domesc Hot Water
temperature in the storage.
15 service Posions of the knob 13 which use is reserved to the technician.
Do not turn the knob 13 on these posions.
16
17 By turning the knob 13 on this posion (hot water stand-by), the storage heang is
completely deacvated and "– –" is displayed. This allows a considerable gas saving,
especially in medium and long term periods in which the hot water availability is not
necessary. The storage an-freeze funcon remains acve. The an-legionella func-
on is disabled.
Commands on the lower side
18 System pressure gauge
19 System lling and pressure restoring cock
20 GAS cock
Commands outside the boiler
Externally the boiler, suitably posioned in the build-
ing (generally by the installer or by the electrician),
two devices that the user should access to, are present.
The presence and the characteriscs of these devices
are prescribed by the regulaon in force.
Two-pole switch: it is located usually close to the boiler and it's for electrically insulang the boiler itself
from the domesc mains power supply network.
00066_00
1819
20

Green Heating Technology
9
Room thermostat: it commands electrically the boiler to acvate or deacvate the heang system, in
order to keep the room temperature (detected by a sensor) within a value set by the user, Regulaon
in force prescribe its posioning, the temperature limits within the user can adjust it and the periods
of heang. On trade are available programmable room thermostats: most of them allow to make a
weekly programming of various temperature levels, besides special programs for various purposes.
We suggest to choose original ITALTHERM accessories.
Typical use
Preliminary operaons
fFirstly, the knob 12 should be on the posion 8 .
fMake sure, by the gauge 18 that the cold-system temperature is always within 0.5 and 1.5 Bar (op-
mal: 1÷1.5 Bar). When the pressure drops below 0.5 Bar, the boiler stops working. In this case, open
the system lling cock 19 up to obtain, on the gauge, a value between 1.0 and 1.5 Bar.
The system pressure raises with the temperature: a too high inial cold-system pressure could
lead to water drain from the 3 Bar safety valve aer the system heang-up.
fMake sure that the gas cock 20 is open.
fMake sure that the boiler is electrically supplied: green light 1blinks.
Boiler acvaon
fRotate the knob 12 on Summer 11 if you want to have only hot water producon, or on Win-
ter 9 if you need both room heang and hot water producon.
fOpening a hot water cock, the burner ignites and, aer a short me (that also depends on the char-
acteriscs of the plant externally the boiler) hot water ows from the cock.
fIn Winter mode, consequently a request by the Room thermostat, the burner ignites and the
produced heat is sent, by means of the system vector liquid, to the heang elements of the building.
If, in the mean me, a Domesc Hot Water request takes place, this laer has the priority for the
whole request me. Since the DHW requests are usually limited in me, they generally don't aect
the room heang.
s
e
r
v
i
c
e
service
8
9
10
12 13
14
15
17
16
11
3
4
67
5
1
2
00056 00

Green Heating Technology
10
Temperature adjustment
Note: correct adjustment leads to creang the condions for energy saving.
fHeang system adjustment: by rotang the knob 12 along the scale 10, the seng of the heang
system temperature is made (the value, during the adjustment, is shown on the display 5). Generally,
in the deep cold season and/or with poor building thermal insulaon (or if you noce that the burner
stays on for a long me, but the room temperature rises too slowly) prefer higher sengs. On the
contrary, if you noce that the room temperature exceeds too much, for thermal inera, the value
set on the room temperature, it's appropriate to decrease the system temperature.
Note: if the Outdoor Sensor Kit
is installed, see also "Out-
door Sensor Kit" on page 51;
if the Remote Control Kit is
installed, see also "Remote
Control Kit" on page 52 and the
relevant instrucon booklet.
Note: don't make confusion be-
tween the heang system
temperature here de-
scribed, with the temperature
of the room set on the Room
Thermostat.
fDomesc hot water adjustment: by rotang the knob 13 along the scale 14, the seng of the
hot water temperature inside the storage, is made (the value, during the adjustment, is shown on
the display 5). On this type of boiler, we suggest to set the knob in such a way to have a comfortable
hot water temperature by drawing only hot water or eventually by mixing it with a lile cold water.
Avoid maximum values if not strictly needed, that will force to mix the hot water with bigger quan-
es of cold water.
A high storage temperature increase the limestone scale of the storage. Also gas consumpon
depends on the set temperature, aside from the quality of the storage thermal insulaon.
Remark: Because of the thermal dissipaon along the pipings, it could be necessary a certain me
before the temperature of the water out of the faucet gets stabilized.
ATTENTION: posions service 15 and 16 are reserved to the technician. Don't turn the knob
on these posions to avoid malfuncons. Should this happen by mistake, turn immediately the
knob 13 on the scale 14.
An-Legionella funcon
With regular periodicity the boiler, in Summer or Winter mode, automacally provides for the heang
of the water in the storage, so as to destroy eventual bacteria (expecially Legionella spp.) which form in
quiet warm water.
Remark: the An-Legionella funcon is not acve when the boiler is in stand-by 8 or in "hot
water Stand-by" 17 mode.
Incidental malfunconing
Avoid performing personally any intervenon that are job of the technician, for example the
ones on the electrical circuits, on hydraulic system or on the gas system, and whatever other
operaon that's not menoned in this "User Guide" secon and expressly allowed to the User.
Always address yourselves to qualied personnel.
s
e
r
v
i
c
e
service
8
9
10
12 13
14
15
17
16
11
3
4
67
5
1
2
00056 00

Green Heating Technology
11
Boilers must be always equipped with original accessories only.
ITALTHERM Srl is not responsible for damages caused by the incorrect, wrong or unreasonable
use of not original materials.
The burner doesn’t turn on
fif the room thermostat (or programmable room thermostat, or similar) is installed, check that it is
really requiring the room heang;
fcheck that the electrical power supply is present and that the Summer/Winter knob isn't posi-
oned on (stand-by) but on Summer or Winter . The GREEN light should be steadily ON
(see details in the paragraph "The front control panel" on page 7);
fif the RED locking light was on or blinking, or if you noce an anomalous behaviour of the light indi-
cators, see the paragraph "Alarms - boiler block" on page 39;
fcheck on the gauge that the boiler pressure is correct (1÷1.5 Bar in a cold state) or at least not below
0.5 Bar;
flet the technician to look up the notes in the paragraph "Electrical diagram" on page 49.
Shortage of domesc hot water producon
fcheck that knob is not set on a too low value or to the “service”posion
fcall a qualied technician to check gas valve regulaon;
fcall a qualied technician to check, and eventually clean, the coil of the DHW storage.
Remark: where the water hardness value is too high, it is suggested the installaon of a soen-
ing device, in order to prevent the limestone precipitaon; this operaon avoids a frequent
cleaning of the coil of the DHW storage.
Boiler inacvity
The eects of the periods of inacvity can be relevant in parcular situaons such as in ats used only
for some months per year, most of all in cold places.
The user will have to decide to put the boiler in the SAFETY SHUT OFF state disconnecng all the sup-
plies, or to leave it in stand-by and use the An Frost Funcon. When there is the possibility of freezing
it is convenient to chose between the advantages and the disadvantages of the SAFETY SHUT OFF and
of the Stand By/An Freezing Way.
Safety shut o
fTurn o the general switch on the Electrical Supply Line of the Boiler;
fClose the Gas Tap;
When it is expected that the temperature is going to decrease under 0°C, call a technician to do
the following:
•Fill the system, included the primary circuit of the storage unit and the relevant coil, with an
an-freezing soluon (unless the system was already lled with said soluon) otherwise it must
be completely emped. Noce that if it had been necessary to restore the pressure (because of
possible loss) in an heang system already lled with an An freezing soluon, the concentraon
of the soluon could have decreased and it could not guarantee the An freezing Protecon.
• let the condense collector syphon be emped unscrewing its inferior cap.

Green Heating Technology
12
•completely empty the hot and cold sanitary water system, including the sanitary circuit and the
tank of the domesc water storage.
Remark: the boiler is equipped with a system which protects the main components from the excep-
onal cases of mechanical lock, due to the inacvity in presence of water and scale. The an-
locking funcon can’t work in Safety shut o mode, because of the lack of electrical supply.
Before re-igning the boiler, have a technician check that the pump is not blocked due to inac-
vity (for the technician: unscrew the plug in the centre of the cap to access the rotor sha and
turn it with a screwdriver or other suitable tool).
Stand-by mode with an-frost & an-locking funcon
When the boiler is le in stand-by during a period of inacvity, it will be protected against freezing by
several funcons provided in the electronic controller, which heat the parts involved when the tempera-
ture falls below factory set values.
The an-frost heang is accomplished by turning on the burner and pump.
In addion, when the boiler is in stand-by, it periodically acvates the main internal components to
avoid rare cases of blockage due to inacvity in the presence of water and lime. This can also occur
when the boiler is locked (red lamp on) provided that the system pressure is correct.
In order for these systems to be acve:
•the boiler must be receiving gas and electricity;
• boiler must be le in stand-by mode (Summer/Winter knob on , green lamp ashing);
• system pressure must be correct (1÷1.5 bar in a cold state, minimum 0.5 bar)
In case of lack of gas, the burner won’t turn on and the boiler will go in LOCK OUT state (red lamp on or
ashing). Nevertheless the pump will work, making the water circulate in the system and reducing in
this way the possibility of freezing.
ATTENTION: the an-frost protecons cannot intervene in the absence of electricity. If you an-
cipate this possibility, we recommend you add a good brand of an-freeze to the heang sys-
tem, following the producer’s instrucons.
We recommend to ask directly the installer/technician about the type of anfreeze product
put in the heang system during installaon.
When the power comes back on, the boiler will check the temperature measured by the two
probes and, if it suspects freezing veried by a parcular automac control cycle, alarm 39 will
be triggered. For more details, see the relave descripon in the paragraph "Alarms - boiler
block" on page 39.
We recommend that you completely empty the hot and cold sanitary water system. The an-
frost funcon does not protect the sanitary circuit outside the boiler.

Green Heating Technology
13
“Ambient An-Frost” Funcon
If the building relevant to the boiler remains unoccupied during cold weather periods, you should con-
sider the chance to extend the protecon against freezing to the whole heang system (and therefore
to the rooms) besides the boiler itself. Also for this funcon, the boiler must be receiving gas and elec-
tricity, and the system pressure must be correct.
fif the Remote Control (original, oponal kit) is installed, the an-freeze funcon is automacally
performed by switching the boiler in stand-by mode by means of the suitable buon on the control
itself. The boiler, the DHW storage, and the rooms will be kept at a minimum temperature that avoids
the freezing of the liquids in them;
fif a common room thermostat or chronothermostat is installed, featuring* the “Ambient An-
Frost” funcon, and you want to use it, it'is necessary to leave the boiler in Winter mode and
NOT in stand-by or in Summer mode) to allow the boiler to acvate when the room tempera-
ture sensor requires the heang. To minimize the gas consumpon, it's also advisable to lower the
storage temperature by turning the DHW temperature knob to the minimum, on , otherwise
the water in the storage will be uselessly kept hot.
* failing this funcon, you can anyway set the room temperature a few degrees above zero, e.g. +5°C (if it's a chronothermostat,
remember to set it to manual mode).
The “Ambient An-Frost” funcon does not protect the sanitary circuit outside the boiler and,
especially, in areas where the heang system doesn’t reach. For this reason, we recommend
that you empty the cold and hot sanitary system, if they were at risk of freezing.
Installaon
Law and regulaon prescripons for the installer
Note for the translator/writer: Place in this paragraph all the recommendaons relevant to the compli-
ance with laws in the desnaon naon/country (if any). As an example (from Italian regulaon):
Characteriscs of the room: as this boiler has an heat output lower than 35 kW (about 30000 Kcal/h),
it is not required to install the appliance in a dedicated room, provided that the room complies with
the regulaon in force and that all installaon rules assuring a safe and regular gas boiler operaon,
are strictly respected.
Permanent venlaon of the installaon room is mandatory and extremely important when
a boiler with air draught from the installaon room (B… appliance type) is installed. Venlaon
must be made and sized in compliance with Laws and Rules in force.
Instrucng the user: at the end of the installaon, the installer must:
• explain the operaon of the boiler and its safety devices to the user;
• give this user this booklet and the documentaon within his/her competence, duly lled in where
required.

Green Heating Technology
14
Dimensions and connecons
10
53
50 250 250
±12
50
±12 ±12
128 90 177 76 69
70 97
60 128 90 120 52 150 60
G
G
L
TA
F
FC CM
M
R
R
600
900
425
439 6893
210
137
88020
11
11
150
163
265
135 G
C
R
M
F
3
1
2
SC SC
TA / L
842
870
848
845
00067_00
Legend:
C DHW outlet (½”)
F Fresh water inlet (½”)
R System return (¾”)
M System ow (¾”)
G Gas: connecon on the boiler ¾”;
on the wall, using the oponal
original ng kit ½”
1 Flue outlet
2 Air inlet for coaxial system
3 Air inlet for split-pipe system
TA/L Indicave posion for electrical
power supply and room
thermostat wirings
TA Room thermostat wiring
L Electrical power supply wiring
SC Indicave posion for the
condensate drain
upper
view
front view -
hydraulic connecons
on the boiler
le side view -
hydraulic connec-
ons on the boiler
City Max 26 K
City Max 32 K
front view -
hydraulic connecons
on the wall
(with oponal ng kit)
Pump capacity diagrams
0
1
2
3
4
5
6
0 200 400 1000 1200600 800 1400
00069
00
pressure (m H2O)
water ow (l/h)
mod. 26K
mod. 32K
speed 3 - 2 of the pump
The graph is referred
to the capacity available
to the system.

Green Heating Technology
15
Warnings for the installaon of oponal kits or special systems
Floor heang system
The safety thermostat(s) that protects the oor against overheang (that could damage the
cladding, the structure or the system itself) must be installed on the ow starng end of the
serpenne embedded in the oor itself. It should not installed on the system ow pipe in prox-
imity of the boiler, otherwise frequent and unjused boiler locks, caused by its triggering, are
possible.
Specicaons for inlet air
Air must be withdrawn from places free of pollutant (like uorine, chlorine, sulfur, ammonia, alkaline or
similar agents). In the event of installaon of the boiler in atmospheres with not negligible presence of
aggressive chemical substances (e.g. hairdressing salons, laundries) we recommend to foresee the air
inlet from outdoor, choosing the type C installaon.
Domesc water supply characteriscs
The cold water inlet pressure must be lower than 8 Bar (higher pressure will lead to the storage safety
valve triggering). Besides, for an opmal boiler funconing, water pressure should be more than 1 Bar.
A lower pressure could make dicult to restore correctly the pressure of the heang system.
In case of higher pressure it is indispensable to install a PRESSURE REDUCER upstream the
boiler.
The cleaning frequency of the storage coil depends on the water supply hardness. If the water hard-
ness is more than 25° fr it’s required to install a soener to bring the hardness below that value.
Besides, the presence of solid residuals or impuries in the water (for example in case of new systems)
could compromise the correct funconing of the boiler. For DHW producon systems, the regulaon in
force prescribes a safety lter to protect the systems.
The condensing burner/exchanger assembly requires parcular characteriscs for the heang
system liquid, more restricve than the ones of the inlet domesc water. See the "Heang" sec-
on of the table "Technical data" on page 45.
Protecon against freezing
Thanks to its anfreeze system, inner components could never reach a temperature lower than 5°C. This
system is acvated when the boiler is supplied by the electrical and gas lines, provided that the pressure
in the heang system is correct.
In case of boiler installaon in rooms where temperature can drop down to 0°, it is advisable
to ll the heang circuit (included the primary circuit of the storage unit and the relevant coil)
with an anfreeze liquid specic for heang systems, propylenic glycol based, following the in-
strucons of its manufacturer. Pay aenon to the correct product concentraon: adding those
substances to the heang water in incorrect dose could lead to the deformaon of the seals and
cause unusual noises during operaon.
ITALTHERM S.r.l. will not be held responsible for consequent damages.
Instruct the User about the anfreeze funcon of the boiler and about the anfreeze product
added in the heang system.

Green Heating Technology
16
Siphon overow drain
The boiler’s siphon is equipped with a supplementary safety discharge SCD
that protects the burner in the very situaon in which the condense does
not from correctly from the drain pipe downstream from the siphon. Since
this is easily accessible from the rear of the boiler, evaluate the opportunity
to use it or not before installing the boiler, by connecng to it a secon of
exible hose 1 suitable for condense. On its other end, the hose 1 should be
inserted, avoiding bends and kinks, in a suitable drain, such as the funnel of
the condense drain or safety valve. Do not pierce the prepared hole 4.
As an alternave, although NOT recommended, you could simply leave the
drain SCD open. The burner will anyway be protected if the siphon gets ac-
cidentally blocked, but the condense (acid) will leak into the environment
and could damage surfaces it touches (such as marble).
Check the seal of siphon, making sure that the caps 2, 3, 5 and 6 are
properly and completely screwed/inserted.
Outdoor installaon in a parally protected place
“City Max xx K” forced draught, condensing mod-
els can be installed outdoor, but only in parally
protected places.
The boiler minimum and maximum working tem-
peratures are menoned in the paragraph "Tech-
nical data" on page 45 and on the boiler data plate.
The materials used for the boiler installaon, in-
cluding the devices and/or the materials used for
thermal insulaon, should be so to maintain their
funconality within the temperature range indi-
cated on the data plate.
If the place where the boiler is located is converted from outdoor to indoor (e.g. veranda) it will
be necessary to verify the compliance of the new conguraon with the laws and rules in force,
and to make the modicaons required.
Posioning and fastening
Remark: A re-usable metal jig ( D in the gure) can be ordered separately, so as to facilitate connec-
ons and xing points posioning (when the original connecon kit is used). If the metal jig and/
or the original connecon kit are not used, refer to the paragraph "Dimensions and connec-
ons" on page 14 for the posion of the connecons directly on the boiler.
fLocate the exact posion of the boiler considering the sucient clearances for maintenance and
servicing: at least 50mm laterally and 300 mm on the lower side
fTo x the boiler with wallplugs (“stud” type with nut), centre the relevant wall holes as regards
to Apoints. To hang it with open hooks, place hooks in correspondence with Bpoints.
00004 00

Green Heating Technology
17
fIf the metal jig is used, hang it on the wall using the same wallplugs or hooks and the holes or slots
indicated in the gure ( Afor the plugs and B for the open hooks).
fFix up the connecons and all ducts for heang ow and return, cold water, hot water, gas and
electrical cables, predisposing them in the holes of the metal jig or respecng the measures in the
paragraph "Dimensions and connecons" on page 14. The upper edge of boiler’s body, used as a refer-
ence in the paragraph "Flue system types" on page 24, is represented by the doed line C in the gure.
fRemove the jig (if used) and hang the boiler to the wallplugs or hooks,
using the holes or slots indicated in the gure ( Afor the plugs and B
for the open hooks).
fRemove the plasc caps placed to close the hydraulic connecons on
the boiler.
fProceed with the hydraulic, gas, electrical and ue connecons follow-
ing the instrucons and warnings reported in the following paragraphs.
The connecons of the boiler are engineered to t plain couplings
with screw ring, interposing a plain gasket of suitable size and ma-
terial, that ensure a reliable seal even without excessive ghten-
ing force. They are NOT suitable for hemp, teon tape or similar
materials
Remark: the lower grid is spare inside packing, not assembled. We sug-
gest to x the grid only at the end of the boiler installaon opera-
ons.
Gas (1/2”)
Hot Water
Outlet (1/2”)
Cold Water
Inlet (1/2”)
Heang
Flow (3/4”)
Heang
Return (3/4”)
Electrical
Power Supply
Room
Thermostat
50
18
10
18
564
128 90 76 6069
70 97
177
250 250
600
20
50
880
A A A
BB
C
D
900
20
18
20
11 9
53
A
B
C
00070 00

Green Heating Technology
18
Hydraulic system (DHW and heang)
Make sure that the hydraulic and heang systems ducts are not used as earth connecons of
the electrical system. They are absolutely NOT SUITABLE for such a use. Besides: they don't
guarantee the earth dispersion; in case of electrical fault they could generate a fulguraon risk;
there could take place galvanic currents in the pipings and consequent corrosion and hydraulic
leaks.
Advices and suggesons to avoid vibraons and noises in the system
fDo not use pipes with reduced diameters;
fDo not use bends with small radius and reducons of important secons.
Cleaning and preservaon of the systems
The eciency, the reliability and the safety of the boilers, as all generic thermal systems and compo-
nents, depend strictly on the features of the water that supply them and on their treatment.
A proper treatment of the water improves the protecon of the systems against corrosions (and there-
fore perforaons, noise, leaks, etc.) and limestone incrustaons that drascally reduce the eciency
of the thermal exchange (consider that 1 mm of limestone incrustaons reduces of 18% the thermal
exchange of the heang element on which it has been formed).
ITALTHERM guarantees its products only if the characteriscs of the water comply with UNI 8065, re-
ported also in laws on energy saving.
Thoroughly wash the heang system with water, before connecng the boiler. This will elimi-
nate residual like welding drops, slag, hemp, masc, mud, rust and other dirt from pipes and
radiators. Otherwise, these substances could enter the boiler and damage the internal compo-
nents (pump etc.).
fIn case of old or very dirty systems, to wash them use specic, proven eciency products, in the
suitable quanty and following the instrucons of its manufacturer.
fIf the water on boiler inlet is harder than 25° fr, it’s required to install a soener to bring the hardness
below that value, as required by the reference regulaon.
fFor oor system and generally all low temperature systems, the water treatment product must have
lming acon (protecon against corrosion and incrustaon) and acon against bacteria and algae.
Heang system
fConnect the safety evacuaon ducts of the boiler to an evacuaon funnel. If safety valves are not
connected to an evacuaon device, their intervenon could ood the room. The manufacturer can-
not be held responsible for any damage arising from that situaon.
Condense drain
Insert the exible pipe of condense outlet inside the outlet funnel (or other inspectable connecon de-
vice) properly installed for this purpose, or in the outlet funnel of the safety valve, in case of the above
menoned outlet is able to receive the acid liquids of the condense as foreseen by the norms in force
in maer of condensing boilers.
The system must be made in order to avoid the condense freezing. Before the acvaon of the
appliance be sure that the condense can be evacuated correctly.

Green Heating Technology
19
System lling and pressuring
Once all system connecons have been carried out, proceed with the lling of the heang system and of
the DHW storage. This operaon should be made with care, respecng the following steps:
The operaons to completely purge the air from the heang system and from the storage coil,
require the acvaon of the boiler, therefore the nal purging must be performed, by qualied
technicians, during the rst starng up.
DHW storage tank lling
1. Load the DHW expansion vessel (see "Boiler internal components" on page 48) to the aqueduct
pressure;
2. open one of the hot water taps in the DHW system;
3. gradually open the hand valve 5 installed on the boiler's cold water inlet connecon;
4. when only water ows out of the tap, close it.
Heang system lling
1. Open the radiators venng devices;
2. Check that the plug of the automac air vent, in-
corporated in the boiler circulator, is unscrewed:
if not, unscrew it and leave it unscrewed, even
aerwards, for normal operaon;
3. If it's required to ll the system with an-freeze
soluon, do this operaon, then hermecally
close the connecon or the valve used to put the
soluon in, to allow the pressurizaon.
4. Gradually open the lling cock 1;
5. Check the correct funconing of automac vent-
ing devices, eventually installed on the heang
system;
6. Close the radiators venng devices as soon as water ows out of them;
7. Make sure, by reading the pressure gauge 2, that the pressure reaches the opmal value of 1.0 bar
(max 1.5 bar);
8. Close the lling cock 1 and bleed each radiator again;
9. Without acvang the boiler, cold purge the storage coil, by using its manual venng valve (item 11
on page 29)
10. Repeat the venng and pressurizaon operaons unl the air is completely purged. The complete
purging needs the acvaon of the pump, so it's possible only during the rst starng up.
00071_00
2
4
5
1
3

Green Heating Technology
20
Gas connecon
Due to various installaon possibilies, the gas cock 3
supplied with the original Connecons Kit has a sim-
ple male Ø ½” connecon, facing the rear of the boiler.
The gas pipe 4, upstream the gas cock 3, should be sup-
plied by the installer.
While connecng the gas inlet of the boiler
to the gas supply piping, it is MANDATORY
to insert a PLAIN GASKET, whose dimensions
and material must be adequate. Connecon
is NOT suitable for hemp, teon strip or simi-
lar materials. Because of the type of ng,
the use of those materials does not make the
suitable seal with consequent gas leaks!
This boiler is designed and prepared to be supplied with Natural Gas G20 (Methane) or Com-
mercial Propane G31. A qualied technician can convert it to operate with one of these two
types of gas above said.
It must never be used with Butane gas G30 (that can be present, pure or mixed with Propane G31,
in the portable gas boles for cookers) therefore, if the boiler is prepared for operaon with
commercial Propane G31, we recommend nofying the supplier of the fuel, for example, by
applying the scker provided with the boiler (or included in the G31 conversion kit), on the gas
tank or in its immediate vicinity, so that it is visible to the employee when it is being relled.
Using Propane gas G31, it is absolutely necessary to install a pressure reducer upstream the
boiler. Failure to do this, the gas valve of the boiler will get damaged.
The gas connecon, as generally the boiler installaon, must be done by qualied personnel as
prescribed by the regulaon in force, because a faulty gas connecon could lead to re, explosion
and other very serious damages to persons, animals and objects. The manufacturer cannot be
held responsible for any damage arising from that situaon.
fVerify what follows:
•cleaning of all system gas pipes in order to avoid the presence of work residuals that could com-
promise the correct boiler funconing;
•gas line and ramp conformity with laws and rules currently in force;
• internal and external ghtness of the gas system and connecons;
• supply pipe must have a secon greater than or equal to the boiler one;
• supply gas must correspond to the one for which the boiler has been set: otherwise, it's manda-
tory to ask to qualied personnel to set the boiler for the correct gas type;
• an intercepon valve must be installed upstream the appliance.
fOpen the meter valve and purge the air that is inside the system pipes (including all the appliances).
00071_00
2
4
5
1
3