Unical Osa S 24 Datasheet

ENGLISH
INSTALLATION AND SERVICING MANUAL
S 24
S 28
S 35
+ TOUCH CONTROL Uy BOX integrate

2
Provisions for proper disposal of the product in accordance with Directive 2002/96/EC
At the end of its life cycle the product must not be disposed of as urban waste. It can be taken to
a special recycling centre managed by the local authorities, or to a dealer who offers this service.
Separate disposal of a domestic appliance avoids possible negative consequences for the
environment and human health deriving from inappropriate waste handling and allows the recovery
of the materials of which it is made, in order to obtain signicant energy and resource savings.
http://www.unicalag.it/prodotti/domestico-50/condensazione-gas/osa/1635/osa-s

3
Technical Features General information
Maintenance instructions Installation Instructions
ENGLISH
Attention: this manual contains instructions for the exclusive use of the professionally qualied installer
and/or maintenance technician in compliance with current legislation.
The user is NOT qualied to intervene on the boiler.
The manufacturer will not be held liable in case of damage to persons, animals or objects resulting from
failure to comply with the instructions contained in the manuals supplied with the boiler.
2 TECHNICAL FEATURES AND DIMENSIONS ..................................................................................................9
2.1 Technical features ...................................................................................................................................9
2.2 Main components view and dimensions ..................................................................................................9
2.3 Available ow rate / pressure diagram ..................................................................................................14
2.4 Operation data .......................................................................................................................................15
2.4.1 Data according to directive ErP ....................................................................................................15
2.4.2 Caratteristiche del controllo integrato Uy BOX ...........................................................................15
2.5 General features .............................................................................................................................15
4 MAINTENANCE INSTRUCTIONS ..................................................................................................................32
4.1 Inspection and maintenance instructions .............................................................................................. 32
4.1.1 Pannello comandi Uy BOX .........................................................................................................33
4.2 Parameters that can be edited from the control panel ..........................................................................35
4.3 Adaptation of the power to the heating system .....................................................................................38
4.3.1 GAC adjustment ..........................................................................................................................39
4.4 Wiring diagram ................................................................................................................................ 43
4.5 Error Code .............................................................................................................................................44
4.5.1 Filling system ................................................................................................................................47
4.6 Important Note .......................................................................................................................................48
4.6.1 Service panel ................................................................................................................................49
3 INSTALLATION INSTRUCTIONS ...................................................................................................................16
3.1 General warnings ..................................................................................................................................16
3.2 Installation standards ............................................................................................................................16
3.3 Preventive system verication and adjustment operations ...................................................................16
3.4 Packaging ..............................................................................................................................................17
3.4 Positioning the boiler .............................................................................................................................18
3.6 Flue gas exhaust pipe connection .........................................................................................................19
3.7 Connections ..........................................................................................................................................22
3.8 Filling the system ...................................................................................................................................23
3.9 Electrical connections ............................................................................................................................24
3.10 Commissioning ................................................................................................................................... 26
3.11 Measurement of combustion efciency during installation ....................................................................27
3.11.1 Calibration function activation ................................................................................................... 27
3.11.2 Probes positioning ....................................................................................................................28
3.12 Burner adjustment .................................................................................................................................29
3.12.1 Combustion adjustment function activation ..............................................................................30
3.12.3 Adaptation of the power to the heating system .........................................................................31
1 GENERAL INFORMATION ...............................................................................................................................4
1.1 General warnings ....................................................................................................................................4
1.2 Symbols used in the manual ...................................................................................................................5
1.3 Appropriate use of appliance ...................................................................................................................5
1.4 Information for system manager ..............................................................................................................5
1.5 Safety warnings .......................................................................................................................................6
1.6 Technical data plate ................................................................................................................................7
1.7 Water treatment .......................................................................................................................................8
1.8 Boiler antifreeze protection ......................................................................................................................8

4
1GENERAL INFORMATION
In the event of failure and/or malfunctioning of the
appliance, switch it off and do not try to repair it or
intervene on it directly. Contact only personnel qual-
ied in compliance with law.
Any repairs must be performed solely by personnel
authorised by Unical AG S.p.A., using original spare
parts only. Failure to comply with the above can com-
promise the safety of the boiler and void the warranty.
To guarantee appliance efciency and its correct
operation, yearly maintenance must be performed
by qualied personnel.
Should you decide not to use the appliance, parts
entailing potential sources of hazard must be made
safe.
Before commissioning an appliance that has not
been used, wash the domestic hot water production
system, making the water ow until it has been fully
replaced.
Should the appliance be sold or transferred to a new
owner or if you move and leave the appliance, always
make sure that the instruction booklet accompanies
it in order to be consulted by the new owner and/or
installer.
Only original accessories must be used for all appli-
ances with optionals or kits (including electric).
This boiler is intended solely for the use for which it
was expressly designed.
Any other use is to be considered improper and
therefore dangerous (*).
1.1 - GENERAL WARNINGS
The instruction booklet is an integral and essential
part of the product and must be kept by the user.
Read the warnings contained in this instruction
booklet carefully as they provide important guidelines
regarding installation, use and maintenance safety.
Keep the booklet with care for further consultation.
Installation and maintenance must be performed
in compliance with the standards in force ac-
cording to the instructions of the manufacturer,
up to standard and by personnel qualied and
certied in compliance with law.
Systems for the production of domestic hot wa-
ter MUST be constructed entirely with compliant
materials.
By professionally qualied personnel we mean:
personnel with specic technical skill in the eld
of heating system components for civil use, do-
mestic hot water production and maintenance.
Personnel must have the qualications provided
for by current legislation.
Incorrect installation or improper maintenance
can cause damage to persons, animals or objects
for which the manufacturer is not responsible.
Before performing any cleaning or maintenance,
disconnect the appliance from the energy mains by
acting on the switch of the system and/or through
the specic cut-off devices.
Do not obstruct the terminals of the intake/exhaust
ducts.

5
1.2 - SYMBOLS USED IN THE MANUAL
Pay special attention when reading this manual to the parts marked by the symbols:
NOTE!
Tips
for the user
ATTENTION!
Possible dangerous
situation for the product
and the environment
DANGER!
Serious danger
to safety
and health
1.3 - APPROPRIATE USE OF APPLIANCE
The boiler has been built according to the current level of engineering and acknowledged
technical safety rules.
Nonetheless, if improperly used, dangers could arise for the safety and life of the user
and other persons or damage to the equipment or other objects.
The appliance is designed to work in heating systems, with hot water circulation, for
the production of domestic hot water.
Any other use is considered improper.
Unical AG S.p.A. will not be held liable for any damage resulting from improper use.
Use according to the intended purposes also includes strict compliance with the in-
structions in this manual.
The user must be instructed concerning the use and operation of his heating system, in particular:
• Deliver these instructions to the user, as well as other documents concerning the appliance
inserted in the envelope inside the packaging. The user must keep this documentation
safe for future consultation.
• Inform the user about the importance of the air vents and the ue gas exhaust system, high-
lighting their essential features and the absolute prohibition of modifying them.
• Inform the user concerning controlling the system's water pressure as well as operations to
restore it.
• Inform the user concerning correct temperature control, control units/thermostats and radiators
for saving energy.
• Please note that, in compliance with the standards in force, the inspection and maintenance of
the appliance must be carried out in compliance with the regulations and frequency indicated
by the manufacturer.
• Should the appliance be sold or transferred to a new owner or if you move and leave the ap-
pliance, always make sure that the instruction booklet accompanies it in order to be consulted
by the new owner and/or installer.
The manufacturer will not be held liable in the event of damage to persons, animals or
objects resulting from failure to comply with the instructions contained in this manual.
1.4 - INFORMATION PROVIDED TO THE USER
NOTE!
For more information
See Technical Info:
from site indicated at pag. 2

6
1.5 - SAFETY WARNINGS
ATTENTION!
The boiler cannot be used by children.
The boiler can be used by adults and only after having carefully read the user’s ma-
nual. Children should be supervised to ensure that they do not play or tamper with
the device.
ATTENTION!
The appliance must be installed, adjusted and maintained by professionally qualied
personnel, in compliance with the standards and provisions in force. Incorrect instal-
lation can cause damage to persons, animals and objects for which the manufacturer
cannot be held responsible.
DANGER!
NEVER attempt performing maintenance or repairs on the boiler on your own initiative.
Any work must be done by professionally qualied personnel. We recommend stipulat-
ing a maintenance contract.
Insufcient or irregular maintenance can jeopardise the operating safety of the appli-
ance and cause damage to persons, animals and objects for which the manufacturer
cannot be held responsible.
Changes to the parts connected to the appliance (once the appliance installation is complete)
Do not modify the following parts:
- the boiler
- the gas, air, water and electricity supply lines
- the ue gas pipe, the safety valve and the exhaust pipe
- the construction parts which affect the operating safety of the appliance
Attention!
To tighten or loosen the screwed ttings, use only appropriate xed spanners.
Incompliant use and/or inappropriate tools can cause damage (e.g. water or gas leakage).
ATTENTION!
Indications for propane gas-red appliances
Make sure that the gas tank has been deaerated before installing the appliance.
For state-of-the-art tank venting, contact the LPG supplier or person qualied in compliance
with the law requirement.
If the tank has not been professionally deaerated, ignition problems could arise.
In that case, contact the supplier of the LPG tank.
Smell of gas
Should a smell of gas be perceived, follow these safety guidelines:
- do not turn electric switches on or off
- do not smoke
- do not use the telephone
- close the gas shut-off valve
- air out the area where the gas leakage has occurred
- inform the gas supplier or a company specialised in installation and maintenance of heating
systems.
Explosive and easily ammable substances
Do not use or store explosive or easily ammable materials (e.g. petrol, paints, paper) in the
room where the appliance is installed.
DANGER!
Do not use the appliance as a supporting base for objects.
In particular, do not place receptacles containing liquids (Bottles, Glasses, Jars or Detergents)
on top of the appliance.
If the appliance is installed inside a housing, do not insert or rest other objects inside this housing.

7
General information
ENGLISH
1.6 - TECHNICAL DATA PLATE
KEY:
1 = CE monitoring body
2 = Type of boiler
3 = Boiler model
4 = Number of stars (directive 92/42 EEC)
5 = (S.N°) Serial Number
6 = P.I.N.ProductIdenticationNumber
7 = Typesofapproveduegasexhaustcongurations
8 = (NOx)NOxClass
A = Heatingcircuitcharacteristics
9 = (Pn) Effective nominal output
10 = (Pcond) Effective output in condensation
11= (Qn)Maximumheatoutput
12= (AdjustedQn)Adjustedforratedheatoutput
13= (PMS)Max.heatingoperatingpressure
14= (Tmax)Max.heatingtemperature
B = Domestichotwatercircuitcharacteristics
15= (Qnw)Ratedheatoutputindomestichotwaterfunction
(if different to Qn)
16= (D)SpecicD.H.W.owrateaccordingtoEN625-EN
13203-1
19= (PMW)Max.domestichotwateroperatingpressure
20= (Tmax)Max.domestichotwatertemperature
C = Electricalcharacteristics
21= Electricalpowersupply
22 = Consumption
23 = Protection rating
D = Countries of destination
24 = Direct and indirect countries of destination
25 = Gas category
26 = Supply pressure
E = Factory settings
27 = Adjusted for gas type X
28 = Space for national brands
G = ErP
29=Seasonalspaceheatingenergyefciency
30 =EnergyefciencyinDHWproductionmode
The rating plate is placed inside the
boiler,
The rating plate DUPLICATE is placed
under the front casing (lower-right).
The CE marking
certies the compliance of the equipment with the
essential safety requirements dened in the directi-
ves and applicable European regulations and that
its functioning satisfy applicable technical stan-
dards.
The CE marking is afxed to each piece of equip-
ment with an appropriate label.
The CE declaration of conformity issued in accor-
dance with international standards by the manu-
facturer, is placed in documentation envelope sup-
plied with the product.

8
(*) The frost protection is always active.
Even disabling the CH and DHW services.
ATTENTION (*) see general warn-
ings 1.1
The heating only models are NOT
suitable for the production of water
for human consumption according
to Ministerial Decree D.M. 174/2004.
ATTENTION!
ANY DAMAGE TO THE BOILER
CAUSED BY THE FORMATION OF
FOULING OR BY CORROSIVE WATER
WILL NOT BE COVERED BY THE
WARRANTY.
1.7 - WATER TREATMENT
The treatment of the supply water
allows to prevent inconveniences
and maintain the functionality and
efciency of the generator over time.
The ideal water pH in heating systems
must be within:
To minimise corrosion, it is crucial to
use a corrosion inhibitor; in order for
it to work properly, the metal surfac-
es must be clean.
(see system protection ACCESSO-
RIES sect. in domestic price list)
VALUE MIN MAX
PH 6.5 8
Hardness [°fr] 915
1.8 - BOILER ANTIFREEZE
PROTECTION (*)
P
O
S
ANTIFREEZE FUNCTION
Power supplies 11 - SR (*) Status
function
antifreeze
Actions
Electric Gas
1ON ON < 6 °C ON - Burner and Pump ON until T > 14°C
2
ON OFF
< 2 °C ON
Only when both the power supplies are ON:
- Burner and Pump OFF until T > 5°C
- When T > 5°C then Burner and Pump
ON until T > 14°C.
OFF ON
OFF OFF
(*) Sensor 11 par. 2.2
This protection can intervene only
i f the electricity and gas supplies are
connected.
I f one of the two is not available and
upon reset 11 (SR) a temperature of
< 2 °C is detected, the appliance will
behave as described in tab. pos 2.
The heating system can be protected
effectively from frost by using
antifreeze products with inhibitor
for heating systems (specific for
multidmetal).
Do not use car engine antifreeze
products as they could damage the
water gaskets.

9
Technical Features
ENGLISH
2
OSA S 24
TECHNICAL FEATURES
AND DIMENSIONS
2.1 - TECHNICAL FEATURES
2.2 - VIEW WITH THE INDICATION OF THE MAIN COMPONENTS AND DIMENSIONS
NOTE!
For more information
See Technical Info
from site indicated at pag. 2

10
OSA S 28 - OSA S 35

11
OSA S 24 - OSA S 28 - OSA S 35
View from above
View from below

12
KEY
N° C.E. S.E. Description
1 db SS Domestic hot water temperature
sensor
2FLS Flow switch with cold water lter
3VG Gas valve
4Fd E.
ACC
/RIL
Ignition/detection electrode
5Burner
8Expansion vessel
10 HL TL Safety thermostat
11 Hb SR Heating temperature sensor
12 Ht P Pump
13 Lp DK Water deciency pressure switch
16 Diverter valve
17 Plate heat exchanger
18 FL
FH
VM Fan
20 Safety valve
22 rb SRR Return temperature sensor
23 tf TLC Flue gas collector safety ther-
mostat
24 Aluminium Heat Exchanger/Ca-
pacitor
25 Vent valve
26 Condensation drain trap
33 Uy BOX (retractable)
34 Gateway (external links)
35 Emergency panel
Aves Connection for additional
expansion vessel
CDomestic hot water outlet G ½
G Gas inlet G ¾
F Cold water inlet G ½
M Heating system ow G ¾
RHeating system return G ¾
Rc Filling valve
Sc Boiler drain
Svs Safety valve drain
Scond Condensation drain
Ufp Smoke rear output optional
C.E. = ERROR CODES see
par. 4.6
S.E. = WIRING DIAGRAM
KEY see par. 4.5

13
Technical Features
ENGLISH
MODULATING PUMP
OSA S 24
OSA S 28 - OSA S 35
2.3 - DIAGRAM OF FLOW RATE/PRESSURE AVAILABLE FOR
INSTALLATION
Flow rate (l/h)
Flow rate (l/h)
Avaible Head (m.c.a.) metres of waterAvaible Head (m.c.a.) metres of water
DIAGRAM OF FLOW RATE/PRESSURE AVAILABLE FOR INSTALLATION

14
2.4 - OPERATING DATA ACCORDING TO UNI 10348
OSA S 24 OSA S 28 OSA S 35
Nominal heat input in CH / DHW mode kW 23,4 28,0 / 33,0 33,0
Minimum heat input with Nat. Gas / Propane kW 3,0 / 3,0 4,4 / 4,4 4,4 / 4,4
Nominal heat output kW 23,02 27,3 32,2
Minimum heat output kW 2,96 4,3 4,3
Nominal output in condensation 50/30 °C kW 23,7 28,9 33,8
Minimum heat output in condensation 50/30 °C kW 3,22 4,68 4,68
Combustion efciency at full load %97,2 97,8 97,3
Combustion efciency at part load %98,6 98,2 98,1
Heat losses through the casing (min.-max.) %1,4 - 1,0 1,1 - 0,2 1,1 - 0,2
(*) Net ue gas temperature tf-ta (max.) °C 56,8 45,1 54,8
Flue gas mass ow rate (min.-max) g/s 1,35 - 10,5 2,0 - 12,5 2,0 - 14,7
Air excess λ %24,3 23,0 23,0
CO2%9,2 - 9,2 9,2 - 9,3 9,2 - 9,3
CO at 0% of O2 (min. - max) ppm 22 - 114 14 - 88 14 - 94
Maximum production of condensate kg/h 3,8 4,5 5,3
NOx class 5 5 5
Chimney heat losses with burner ON (min. - max.) %1,4 - 2,8 1,8 - 2,2 1,9 - 2,7
Chimney heat losses with burner OFF %0,35 0,34 0,34
Max. available pressure at the chimney base min. / max. Pa 2 / 70 2 / 70 2 / 70
Notes: (*) Room Temperature = 20°C Data obtained with appliance operated with Nat Gas (G20)
2.4.1 - DATA ACCORDING TO ErP DIRECTIVE
Description Symbol Unit OSA S 24 OSA S 28 OSA S 35
Nominal Heat Output Pnominale kW 23 27 32
Seasonal space heating energy
efciency ƞs% 94 94 94
Seasonal efciency class in
heating mode A A A
Integrated Weather compensator and
room sensor Classe VI %4 4 4
Seasonal space heating energy
efciency of package
ƞs
Packaging %98 98 98
Seasonal space heating energy
efciency class of package A+ A+ A+
For CH only and combination boilers: useful heat output
Useful Heat Output in high-tempera-
ture regime
(Tr 60 °C / Tm 80 °C)
P4kW 13 16 18,4
Useful efciency at nom. heat output
in high-temperature regime
(Tr 60 °C / Tm 80 °C
ƞ4%88,7 88,9 88,7
Useful heat output at 30% of nom.
heat output in low-temperature
regime (Tr 30 °C)
P1kW 4,3 5,3 6,1
Useful efciency at 30% of nom. heat
output in low-temperature regime
(Tr 30 °C)
ƞ1%99,2 98,1 98,2
Range-rated boiler: YES / NO YES YES YES
Auxiliary electricity consumption
At full load elmax kW 0,085 0,093 0,093
At part load elmin kW 0,012 0,015 0,015
In stand-by mode PSB kW 0,003 0,001 0,001
Other items
Stand-by heat loss Pstb kW 0,0824 0,113 0,113
Emissions of nitrogen oxides NOx Mg/kWh 41 36 39
For CH & DHW production boilers
Declared load prole L XL XL
Energy efciency in DHW production
mode ƞwh % 84 86 86
Daily electricity consumption Qelec kWh 0,0644 0,0813 0,0813
Daily fuel consumptionl Qfuel kWh 14,41 22,97 22,97
Inside sound power level Lwa dB (A) 53 54 54
Seasonal efciency class
in DHW production mode A A A
Fortheadjustmentdata:NOZZLES-PRESSURES-DIAPHRAGMS-FLOWRATES-CONSUMPTIONSrefertotheparagraphADAPTATIONTOOTHERTYPESOFGAS.

15
Technical Features
ENGLISH
2.4.2 - FEATURES OF INTEGRATED Uy BOX
OSA S 24 OSA S 28 OSA S 35
Appliance category II2H3P II2H3P II2H3P
Minimum heat. circuit output (∆t 20 °C) l/min 2,1 3,06 3,08
Minimum heating circuit pressure bar 0,5 0,5 0,5
Maximum heating circuit pressure bar 3 3 3
Primary circuit content l 2,2 2,2 2,2
Maximum operating temperature in heat. °C 85 85 85
Minimum operating temperature in heat. °C 30 30 30
Expansion vessel total capacity l 9 (6+3) 6 6
Expansion vessel pre-load bar 1 1 1
Maximum system capacity (max temp. calc.) l 185 123 123
Minimum domestic hot water circuit ow rate l/min. 2 2 2
Minimum domestic hot water circuit pressure bar 0,5 0,5 0,5
Maximum domestic hot water circuit pressure bar 6 6 6
Domestic hot water specic ow rate (∆t 30 °C) ‘‘D’’ l/min. 11,2 16 16
Domestic hot water ow rate limiter l/min. 10 15 15
Production of D.H.W. in continuous operation with ∆t 45 K l/min. 7,3 10,3 10,3
Production of D.H.W. in continuous operation with ∆t 40 K l/min. 8,3 11,6 11,6
Production of D.H.W. in continuous operation with ∆t 35 K l/min. 9,4 13,3 13,3
Production of D.H.W. in continuous operation with ∆t 30 K l/min. 11,0 15,5 15,5
Production of D.H.W. in continuous operation with ∆t 25 K (*) l/min. 13,2 18,6 18,6
Voltage/Frequency electric power supply °C
35-60 35-60 35-60
Fuse on the power supply V-Hz 230/50 230/50 230/50
Maximum absorbed output A (F) 3,15 3,15 3,15
Protection rating IP X4D X4D X4D
Net weight boiler kg 41 41 41
Gross weight boiler kg 45,7 45,7 45,7
Net weight front case (shell) kg 3 3 3
Gross weight front case (shell) kg 4,9 4,9 4,9
F factor 12 2
R factor
(*) mixed
Uy BOX control panel, togheter with room sensor temperature and outer sensor temperature
provided as standard, performs the environmental thermoregulation work as described in the document
2014/C 207/02, section 6.1.
Class VI – Weather compensator and room sensor, for use with modulating heaters: A heater ow tem-
perature control that varies the ow temperature of water leaving the heater dependant upon prevailing
outside temperature and selected weather compensation curve. A room temperature sensor monitors
room temperature and adjusts the compensation curve parallel displacement to improve room comfort.
Control is achieved by modulating the output of the heater.
2.5 - GENERAL FEATURES

16
3INSTALLATION INSTRUCTIONS
ATTENTION!
This boiler is intended solely for
the use for which it was expressly
designed. Any other use is to be
considered improper and therefore
dangerous.
This boiler heats water at a temper-
ature lower than the atmospheric
pressure boiling temperature.
Before connecting the boiler, have pro-
fessionally qualied personnel:
a)Thoroughly wash all the piping of
the system to remove any residues
or impurities which could jeopard-
ise proper operation of the boiler,
even from a hygienic point of view.
b) Check that boiler is set up to oper-
ate with the available type of fuel.
This can be seen written on the
package and on the technical feature
plate;
c) Check that the chimney/ue has an
appropriate draught, without any
bottlenecks, and that no exhausts
from other appliances are inserted,
unless the ue has been implement-
ed to accommodate several utilities
according to specic standards and
regulations in force. Only after this
check can the fitting between the
boiler and chimney/ue be mounted;
ATTENTION!
If there is dust and/or if there are
aggressive/corrosive vapours
present in the installation room,
the appliance must be protected
suitably and must be able to
operate independently from the air
in the room.
ATTENTION!
Only mount the appliance on a closed
wall, made of non-ammable materi-
al, at, vertical so that the minimum
distances required for installation and
maintenance can be observed.
The boiler must be connected to a cen-
tral heating system and/or domestic hot
water supply network compatible with its
efciency and output.
3.1 - GENERAL WARNINGS
NOTE!
For more information
See Technical Info
from site indicated at pag. 2
NOTE!
For more information
See Technical Info
from site indicated at pag. 2
3.2 - INSTALLATION STANDARDS
It must be installed by a professionally qualied
technician, who shall take the responsibility of
observing all local and/or national laws published
in the ofcial journal, as well as the applicable
technical standards.
3.3 - PREVENTIVE VERIFICATION
AND VERIFICATION AND AD-
JUSTMENT OPERATIONS
NOTE!
For further details relating to the
standards, rules and regulations
for safe installation of the thermal
unit, refer to the section "Technical
Information" on the boiler page of
the www.unicalag.it website

17
ENGLISH
Installation Instructions
BOILER
OSA S P
Depth
L
Width
H
Height
200 mm 540 mm 1010 mm
SHELL
OSA S P
Depth
L
Width
H
Height
62 mm 592 mm 1000 mm
23
1
The OSA boiler is supplied completely assembled
in a sturdy cardboard box.
After having removed the appliance from
the packaging, make sure that the supply
is complete and undamaged.
The packaging elements (cardboard
box, straps, plastic bags, etc.) must be
kept out of the reach of children as
they are potential sources of danger.
Unical AG S.p.A. will not be held liable
As well as the appliance, the packaging contains:
A DOCUMENTATION ENVELOPE
- User operating instructions booklet
- Instruction booklet for the installer and
maintenance engineer
- Warranty
- 2 Spare parts form
- Certicate of conformity
- Gas conversion label
B - Connection predisposition paper template
D - Chimney spacer
E - Bracket for xing
F - Uy BOX
G - Outer sensor + Remote temperature sensor
3.4 - PACKAGING
for damage to persons, animals or objects due to
failure to comply with the instruction above.

18
OSA S 24 - OSA S 28 - OSA S 35
When choosing the place of the installation of the
appliance, follow the safety instructions below:
- Place the appliance in rooms protected from frost.
- Avoid installation in rooms with a corrosive or very
dusty atmosphere.
- The appliance must only be installed on a vertical
and solid wall which can support its weight.
- The wall must not be made of ammable material.
Since the temperature of the wall on which the boil-
er is installed and the temperature of the coaxial
exhaust pipe do not exceed, in normal operating
conditions, a room temperature beyond 60 K, it is
not necessary to observe the minimum distances
from ammable walls.
For boilers with double intake and exhaust pipes, in
the event of crossing ammable walls, insert insula-
tion between the wall and the ue gas exhaust pipe.
3.5 - POSITIONING THE BOILER
Clearance

19
ENGLISH
Installation Instructions
3.6 - FLUE GAS EXHAUST PIPE CONNECTION FOR BOILERS WITH FORCED DRAUGHT
To connect the ue gas exhaust pipe, local and na-
tional standards must be observed
In the event the boiler is replaced, ALWAYS re-
place the ue gas pipe as well.
The boiler is type approved for the exhaust congu-
rations listed below:
C13x C13
% Slope towards inlet = 3%
TOTAL LENGTH (LA intake + L Exhaust)
COAXIAL Ø60/100 DOUBLE Ø80
FROM [m] TO [m] FROM [m] TO [m]
1 5,5 1 + 1 40
(20A+20S)
COAXIAL Ø80/125 DOUBLE Ø60
FROM [m] TO [m] FROM [m] TO [m]
1 8 1 + 1 20
(10A+10S)
Distance between air
inlet pipe and ue gas
exhaust pipe: min 250
mm - max 500
Horizontal exhaust and intake terminals directed
outside via coaxial or double pipes..
C33x C33
TOTAL LENGTH (LA intake + L Exhaust)
COAXIAL Ø60/100 DOUBLE Ø80
FROM [m] TO [m] FROM [m] TO [m]
1 7 0,5 + 0,5 40
(20A+20S)
COAXIAL Ø80/125 DOUBLE Ø60
FROM [m] TO [m] FROM [m] TO [m]
1 9 1 + 1 20
(10A+10S)
ertical exhaust and intake terminals directed out-
side via coaxial or double pipes.
C53x C53
C53 NOT ALLOWED C53
TOTAL LENGTH (LA intake + L Exhaust)
DOUBLE Ø80 DOUBLE Ø60
FROM [m] TO [m] FROM [m] TOA [m]
1 + 1 40
(max 30 S) 1 + 1 20 (max 15 S)
Separate combustion air intake and combustion
products evacuation pipes.
These pipes can discharge into areas with different
pressure.
C43x C43
Collective chimney ue system, consisting of two
pipes, one for combustion air intake and the other
one for combustion products evacuation, coaxial
or double.

20
B23P
TOTAL LENGTH (LS)
DOUBLE Ø80
FROM [m] TO [m]
1 30
Connection to a combustion products evacuation
pipe outside the room; the combustion air is tak-
en directly from the room where the appliance is
installed.
ATTENTION:
For the type of connection B23P the
room follows the same installation rules
for boilers with natural draught.
Please note:
These values relate to exhausts/
made by means of rigid pipes and
smooth original UNICAL.
CAUTION
LT total length is a reference value
for the dimensioning of the ducts of A
(intake) and S (Exhaust). Subtracting
the values of LT reported, at values of
bends* / terminals* / extensions* you
get the value:
if > 0 = OK - POSSIBLE conguration
if < 0 = NO - WRONG conguration
(*) Values in the MT018 available on the website.
C83x C83
Connection to a terminal for combustion air intake
and ue gas exhaust via a single or collective
chimney.
C93x C93
Air / ue gas through concentric pipes in the boiler
room and single pipes in the chimney (combustion
air with counterlow in the chimney)
C63x C63
Boiler intended for connection to a combustion air
intake and combustion products evacuation system,
approved and sold separately
ATTENTION:
The ue must comply with standards
in force.
NOTE!
For more information
See Technical Info
from site indicated at pag. 2