Ferroli OPTIMAX 25 S Troubleshooting guide

OPTIMAX 25 S
wall-mounting gas boiler,
pre-mixed
condensing system boiler
INSTRUCTIONS FOR USE INSTALLATION AND MAINTENANCE
cod. 3544696/5 - 05/2005
G C N° 41-267-22

Optimax 25 S
2
IMPORTANT
Your "benchmark" Installation, Commissioning and Service Record Log Book is enclosed in the
last pages of this manual. “This record must be completed and left with the end user”.
Ferroli is a member of the Benchmark initiative and fully supports the aims of the programme.
Benchmark has been introduced to improve the standards of installation and commissioning of central
heating systems in the UK and to encourage the regular servicing of all central heating systems to
ensure safety and efficiency.
Please see installation and servicing guidelines.
• Read the warnings given in this manual thoroughly.
They provide important information for safe instal-
lation, use and maintenance
• Keep the manual carefully for future consultation.
• The instruction manual is an integral and essential
part of the product and must be kept safely by the
user.
• If the appliance is sold or transferred to another
owner or if the owner moves, leaving the appliance
behind, always ensure that the manual is kept with
the appliance for consultation by the new owner
and /or installer.
• Incorrect installation or poor maintenance absolves
the manufacturer from all liability for damage to
people or property.
• Installation and maintenance must be carried out
in conformity with current legislation, according
to the manufacturer’s instructions and by qualified
personnel.
• Before cleaning or maintenance, disconnect the
appliance from the mains via the switch on the
appliance or a suitable isolating device.
• In the event of malfunction or faulty operation, switch
off the appliance. Do not attempt to repair or carry
out any other operation on the appliance directly.
Contact qualified personnel only.
• Repairs or the replacement of components must be
carried out exclusively by qualified personnel using
original spare parts only. Failure to respect the above
my compromise the safety of the appliance.
• To guarantee efficient operation, the appliance must
be serviced once a year by an authorised service
centre.
• The appliance may not be used for purposes other
than those for which it was explicitly designed. Any
other use is considered improper and therefore dan-
gerous.
• Incorrect installation and use or failure to follow the
instructions provided by the manufacturer absolve
the manufacturer from all liability for damage.
• After unpacking, check that thecontents are complete
and undamaged.
• Keep packing out of reach of children as it is poten-
tially hazardous.
• To clean external parts, use a damp cloth moistened
with soapy water if necessary. Avoid using abrasive
cleaning products and solvents.
This symbol indicates “Caution” and is placed next to all safety warnings. Strictly
follow these instructions in order to avoid danger and damage to persons, animals
and things.
This symbols calls attention to a note or important notice professionally qualified
personnel.
President and Legal Representative
Cav. del Lavoro
Dante Ferroli
Declaration of conformity
Manufacturer: FERROLI S.p.A.
Address: Via Ritonda 78/a 37047 San Bonifacio VR Italy
declares that this unit complies with the following EU directives:
Gas Appliance Directive 90/396
Efficiency Directive 92/42
Low Voltage Directive 73/23 (amended by 93/68)
Electromagnetic Compatibility Directive 89/336 (amended by 93/68)

Optimax 25 S
3
1. OPERATING INSTRUCTIONS..................................................................4
1.1 Introduction ............................................................................................................4
1.2 Control panel ..........................................................................................................5
1.3 Turning ON and OFF ..............................................................................................6
1.4 Adjustments ............................................................................................................6
1.5 Maintenance............................................................................................................7
1.6 Faults.......................................................................................................................7
2. INSTALLATION .......................................................................................8
2.1 General Instructions................................................................................................8
2.2 Boiler location .........................................................................................................9
2.3 Water connections ................................................................................................10
2.4 Connection to the gas system..............................................................................12
2.5 Electrical Connections ..........................................................................................12
2.6 Flue system ...........................................................................................................15
2.7 Condensate outlet connection .............................................................................21
3. SERVICE AND MAINTENANCE............................................................23
3.1 Adjustments ..........................................................................................................23
3.2 System start-up.....................................................................................................23
3.3 Maintenance..........................................................................................................24
3.4 Troubleshooting....................................................................................................26
4 TECHNICAL CHARACTERISTICS AND DATA.........................................28
4.1 Dimensions and connections ................................................................................28
4.2 General view and main components ....................................................................29
4.3 Hydraulic diagram.................................................................................................30
4.4 Technical data table..............................................................................................31
4.5 Diagrams ...............................................................................................................32
4.6 Wiring diagram .....................................................................................................33
BENCHMARK ...........................................................................................34

4
Optimax 25 S
1. OPERATING INSTRUCTIONS
1.1 Introduction
Dear Customer,
Thank you for choosing Optimax 25 S, a FERROLI wall-mounted boiler of the latest generation, featuring
advanced design and cutting-edge technology.
Optimax 25 S is a high-efficiency condensing pre-mix appliance for heating with extremely low emis-
sions, running on natural gas or LPG.
The boiler consists of an aluminium laminar heat exchanger providing effective condensation of the
water vapour contained in the flue gases, permitting extremely high efficiency.
Above the heat exchanger, in the boiler, there is a pre-mix burner, with a large ceramic surface, equip-
ped with electronic ignition and ionization flame control, which achieves extremely low emissions while
ensuring high reliability and long life operation.
The boiler is totally room sealed from the installation room: the air needed for combustion is drawn
from outside. The boiler also includes a modulating speed fan, modulating gas valve, pumps, expansion
vessel, safety valve, flow sensor, temperature sensors, a safety thermostat and a low pressure sensor.
Thanks to the twin microprocessor control and adjustment system with advanced self-diagnosis, unit
operation is for the most part automatic. The power for heating is automatically governed by the control
system according to the indoor and outdoor characteristics (with an optional outdoor sensor installed),
the characteristics of the building and of its location.
The user only has to set the temperature desired inside the home (by means of an optional room thermostat
or remote control, which is required under the building regulations 2002) or regulate the temperature of
the system. The adjustment and control system will provide optimum operation throughout the year.
The display continuously provides information on the unit’s operating status and it is easily possible
to obtain additional information on the sensor temperatures, set-points, etc. or configure them. Any
operating problems associated with the boiler or system is immediately signalled by the display and, if
possible, corrected automatically.

5
Optimax 25 S
1.2 Control panel
23 41
fig. 1
1 - System temperature adjustment / Summer/Winter selection
This knob is used to adjust the system temperature and can switch over between summer / winter. To
increase the system temperature, turn the knob clockwise; anticlockwise to decrease it. To select the
summer mode, turn it anticlockwise to the minimum setting.
2 - ON-OFF / Reset / Test
Holding the key down for at least 5 seconds turns off the boiler. To turn it back on, press the key again
for 5 seconds.
Pressing the key resets boiler operation after a shutdown or lock-out.
Pressing the key 3 times within 5 seconds automatically takes you to TEST operation.
3 - Multi-function
In combination with the reset key, this is used to access the Installer menu.
4 - Operating display
On stand-by and during boiler operation this indicates the boiler operating temperature, a flame (point
at bottom lit up) or a fault code if a problem occurs.

6
Optimax 25 S
1.4 Adjustments
Room temperature adjustment (with room thermostat on)
Using the room thermostat, set the temperature desired in the rooms. Controlled by the room thermo-
stat, the boiler lights and heats the system water to the set system delivery setpoint temperature. The
boiler turns off when the desired temperature in the rooms is reached.
If the room thermostat or the remote control are not installed the boiler will keep the system at the set
system delivery setpoint temperature.
Heating temperature setting
To set the system delivery temperature, turn the knob (ref. 1 - fig. 1). It can be varied from a minimum
of 30 °C to a maximum of 90 °C.
Turning the knob sets the required temperature (clockwise to increase, anticlockwise
to decrease) that is shown on the display. During the setting, the display quickly blinks
and once defined it stops blinking after 2 sec. and goes back to showing the actual
operating temperature.
Summer/Winter selection
To select Summer/Winter, use knob 1 (fig. 1).
Turning it onto (Summer) turns off the heating function but the frost protection stays on.
Turning it onto (Winter) turns on heating.
If the boiler is also used for hot water production do not select the summer position as this will
turn this off also.
1.3 Turning ON and OFF
Ignition
• Open the gas isolation valve on the boiler.
• Purge the gas supply.
• Turn on the electrical switch or insert the plug of boiler.
• The boiler is now ready to function automatically whenever the external controls are calling for
heat.
Turning off
Press the key for 5 seconds (see fig. 1).
When the boiler is turned off with this key, the electronic card is still powered, heating operation is
disabled and the display appears but the frost protection is still active.
Close the gas cock ahead of the boiler and disconnect electrical power.
To avoid damage caused by freezing during long shutdowns in winter, it is advisable to drain all
water from the system.

7
Optimax 25 S
Before calling the FERROLI Caresafe, check that the problem is not due to there being no gas
or electricity.
1.5 Maintenance
It is strongly recommended that an annual maintenance of the boiler is carried out by a qualified gas
engineer. Please refer to the “maintenance” section in this manual.
The casing, the control panel and the aesthetic parts of the boiler can be cleaned using a soft and damp
cloth.
do not use abrasives or solvents.
1.6 Faults
In the event of operating problems, the display blinks and a fault identification code appears.
Listed below are the faults that can be caused by simple, user-detectable problems.
The boiler is equipped with an advanced self-diagnosis system. In the event of trouble with the boiler,
the display will show the fault code. There are faults that in order to restore operation it suffices to
press RESET (2 - fig. 1); if the boiler fails to start, it is necessary to resolve the fault indicated by the
operating LEDs (faults from 1 to 25); other faults cause temporary shutdown that are automatically reset
as soon as the value comes back within the boiler’s normal working range (faults from 30 to 39).
Example
Boiler failed to light
Insufficient system pressure
Make sure that the gas isolation valves up-stream of the boiler
and on the meter are open.
Press the RESET button (2 Fig. 1).
Fill the system to 1-1.5 bar by use of the filling loop.
Fault CureDISPLAY
If the problem remains afther two attempts at resetting, contact your nearest FERROLI Caresafe.
For other faults, refer to section 3.4 “Troubleshooting”.

Optimax 25 S
8
2. INSTALLATION
2.1 General Instructions
This device must only be used for the purpose for which it is specifically designed. This unit is
designed to heat water to a temperature below boiling point and must be connected to a hea-
ting system and/or a water supply system for domestic use, compatible with its performance,
characteristics and its heating capacity. Any other use is considered improper.
BOILER INSTALLATION MUST ONLY BE PERFORMED BY QUALIFIED PERSONNEL, IN ACCORDANCE
WITH ALL THE INSTRUCTIONS GIVEN IN THIS TECHNICAL MANUAL, THE PROVISIONS OF CURRENT
LAW, THE RECOMENDATION OF BS STANDARDS, ANY LOCAL REGULATIONS AND THE RULES OF
COMPETENT WORKMANSHIP.
Incorrect installation can cause damage or physical injury for which the manufacturer declines any
responsibility.
This appliance must be installed strictly in accordance with these instruc-
tions and regulations:
The Gas Safety Regulations (Installations & Use).
The Local Building Regulations.
The Building Regulations (Part L).
The Buildings Standards (Scotland - Consolidated) Regulations.
British Standards Codes of Practice:
B.S. 5440 Part 1 Flues
B.S. 5440 Part 2 Air supply
B.S. 5449 FORCED CIRCULATION HOT WATER SYSTEMS
B.S. 6798 INSTALLATION OF GAS FIRED HOT WATER BOILERS
B.S. 6891 GAS INSTALLATIONS
B.S. 7671 IEE WIRING REGULATIONS
B.S. 4814 SPECIFICATION FOR EXPANSION VESSELS
B.S. 5482 INSTALLATION OF LPG
B.S. 7593 TREATMENT OF WATER IN DOMESTIC HOT WATER CENTRAL HEATING
SYSTEMS
B.S. 5546 INSTALLATION OF HOT WATER SUPPLIES FOR DOMESTIC PURPOSES
Model Water Bye Laws
B.S. 5955-8 PLASTIC PIPEWORK INSTALLATION
For Northern Ireland the rules in force apply

Optimax 25 S
9
2.2 Boiler location
The unit’s combustion circuit is sealed off from
the installation room. The installation room
must be sufficiently well ventilated to prevent
any dangerous conditions from forming in the
event of even slight gas leakage. This safety
standard is required by the EEC Directive no.
90/396 for all gas units, including those with a
so-called sealed chamber.
Therefore the place of installation must be
free of dust, flammable materials or objects
or corrosive gases. The room must be dry and
not subject to freezing.
The boiler is designed to be installed on a solid
wall. The wall fixing must ensure a stable and
effective support for the appliance, using the
bracket and fixings supplied.
If the unit is enclosed in cupboard or moun-
ted alongside, there must be space for normal
maintenance work. Fig. 2 and tab. 1 give the
minimum clearances to leave around the unit.
> 600 mm
Minimum Recommended
A
B
D
30 mm
200 mm
15 mm
(via an openable panel)
300 mm
300 mm
C280 mm 300 mm
Table 1
fig. 2
A A
B
D
C

Optimax 25 S
10
2.3 Water connections
The heating capacity of the unit should be previously established by calculating the building’s heat
requirement according to current regulations. For good operation and long life of the boiler, the plum-
bing system must be well proportioned and always complete with all those accessories that guarantee
regular operation and running.
If the flow and return pipes follow a path where air pockets could form in certain places, it is advisable
to install air vents at these points. Also, install a drain plugs at the lowest point in the system to allow
its complete emptying.
If the boiler is installed at a lower level than the system, it is advisable to provide a non-return valve to
prevent the natural circulation of system water.
The temperature differential between the flow and the return to the boiler should not exceed 20° C
(11° recommended).
Do not use the water system pipes to earth electrical appliances.
Before installation, carefully clean all the pipes of the
system to remove residues or impurities that could affect
the unit’s good working. Flush system in accordance with
BS 7593.
Make the connections to the corresponding connections
as shown in Fig. 3.
Key
1 CH flow (22 mm with isolation valve)
2 Gas inlet (22 mm with isolation valve)
3 Condense outlet
4 CH return (22 mm with isolation valve)
It is advisable to install isolation valves between the boiler and heating system allowing the boiler to be
isolated from the system if necessary.
The safety valve outlet must be connected to a tun-dish or collection pipe to prevent water flowing
out onto the ground in the event of over-pressure in the heating circuit. If this is not done, and the
drain valve trips and floods the room, the boiler manufacturer is not to be held responsible.
Make the boiler connection in such a way that its internal pipes are free of stress.
fig. 3
40 124 186
400
50
196.5
135.5
135.5
1 2 3 4
151
169

Optimax 25 S
11
The connecting kits shown in Fig. 4 are supplied as standard.
Key
A=Nut
B = Compression olive
D=3/4” seal - Green
F = 1/2” gas seal - Blue
Flow isolation valve
Gas isolation valve
AB
F
AB
D
AB
D
Return isolation valve
fig. 4
Make Up Water
Provision must be made for replacing water lost from the sealed system. Reference should be made
to BS6798, for methods of filling and making up sealed systems. There must be no direct connection
between the boiler's central heating system and the mains water supply. The use of mains water to
charge and pressurise the system directly, is conditional upon the Local Water Byelaws. Again any such
connection must be disconnected after use. The supplied temporary filling loop is shown in fig. 4. Ensure
the filling point is on the return pipe to the boiler.
Attention - is drawn to the Model Water Byelaws.
Fittings manufactured from duplex (alpha-beta) brass are not acceptable for underground use and certain
water undertakings will not accept their use above ground.
Key
1. Filling point C.H.
2. Temporary connection
3. Cold water supply
4. Double check valve
Fig. 5
3
2
1
4

Optimax 25 S
12
Water treatment
If treatment is used ferroli limited recommanded only the use of Fernox or Sentinel water treatment
products, which must be used in accordance with the manufactures instructions. for further information
contact:
Fernox Manufacturing Co. LTD. Sentinel Division
Cookson Electronics, Farsyth Road Betz Dearborn LTD
Woking, surry, GU21 5RE Widnes, Cheshire WA8 8ND
Tel: [phone] Tel: [phone]
Note - If the boiler is installed in an existing system any unsuitable additives must be removed by tho-
rough cleansing. All systems should be cleansed according to B.S. 7593.
Note - In hard water areas treatment to prevent lime scale may be necessary.
Note - It is important that the correct concentration of the water treatment product is maintained in
accordance with the manufacturers instructions.
2.4 Connection to the gas system
If necessary the local Gas supplier should be consulted, at the installation planning stage, in order to
establish the availability of an adequate supply of gas.
An existing service pipe must not be used whitout prior consultation with the local Gas supplier.
A gas meter can only be connected by the Local Gas supplier, or by a Local Gas suppliers Contractor.
Installation pipes should be fitted in accordance with BS6891.
Appliance inlet working pressure must be 20mbar MINIMUM, for NG and 37 mbar minimum for LPG.
Do not use pipes of a smaller size than the boiler inlet gas connection (22 mm).
The complete installation must be tested for gas soundness and purged as described in BS689.
All pipework must be adquately supported. An isolating gas valve is provided and should be
fitted on the boiler gas inlet. Please wait 10 minutes when ligthing from cold before checling gas
rate. Gas pressures should be checked afther the boiler has operated for 10 minutes to reach
thermal equilibrium.
The connecting kits shown in Fig. 4 are supplied as standard.
2.5 Electrical Connections
The unit must be installed in conformity with current national and local regulations.
Connection to the electrical grid
The boiler must be connected to a single-phase, 230 Volt-50 Hz electric line.
The unit’s electrical safety is only guaranteed when correctly connected to an efficient earthing
system executed according to current safety standards. Have the efficiency and suitability of the
earthing system checked by professionally qualified personnel. The manufacturer is not responsible
for any damage caused by failure to earth the system. Also make sure that the electrical system
is adequate for the maximum power absorbed by the unit, as specified on the boiler dataplate,
in particular ensuring that the section of the system’s cables is suitable for the power absorbed
by the unit.
The boiler is prewired and provided with a cable for connection to the electricity line. The connections to
the supply must be made with a permanent connection and equipped with a double pole switch whose
contacts have a minimum opening of at least 3 mm, and fused at max. 3A between the boiler and the
line. It is important to respect the polarities (LIVE: brown wire / NEUTRAL: blue wire / EARTH: yellow-
green wire) in making connections to the electrical supply.

Optimax 25 S
13
Central heating request
The heat demand can be done by the room thermostat (terminal 4-5) or by a switch line 230 V phase
(terminal 4).
Standard Systems
For a general pipe layout and wiring diagram on the “S” and “Y” plan systems please see fig.
6a, 6b, and 7a, 7b.
OPTIMAX “S” Plan
Pipe layout
Wiring diagram
OPTIMAX
FERROLI
BOILER
D.H.W.
Zone Valve
C.H.
Zone Valve
Automatic
bypass
(mimimum flow of 6l/min.)
Auto air vent
4321
Junction Box
NEL
Terminal 4 - SWITCH LINE
12345678910
PROGRAMMER
DHW ON
CH ON
NEUTRAL
LIVE
CH
zone
valve
DHW
zone
valve
Room Thermostat
Cylinder Thermostat
N
E
L
230 Vac
fused at
3 amps
BROWN BLUE
GREY ORANGE
L
5
Fig. 6a
Fig. 6b
Remove
connection
between
terminals 4-5

Optimax 25 S
14
OPTIMAX “Y” Plan
Pipe layout
OPTIMAX
FERROLI
BOILER
Auto air vent
Automatic
bypass
(mimimum flow of 6l/min.)
Wiring diagram
4321
Junction Box
NL
12345678910
PROGRAMMER
NEUTRAL
LIVE
CH ON
DHW ON
DHW OFF
BLUE
WHITE
GREY
ORANGE
Room Thermostat
Cylinder Thermostat
N
E
L
240 Vac
fused at 3 amps
Honeywell V4073H mid position
The heating system must have an automatic
bypass capable of
passing 6 litres/minute
3 WAY ZONE VALVE
2
1
C
Terminal 4 - SWITCH LINE
L
5
fig. 7a
fig. 7b
Remove
connection
between
terminals 4-5

Optimax 25 S
15
Room thermostat
REMOVE CONNECTIONS 4 - 5 IF EXTERNAL CONTROL FITTED.
WARNING: the room thermostat works at 230V.
fig. 8
System
external
controls
5
4
3
2
1
Switch Line 230V
L
N
fig. 9
The user must never change the unit’s power cable. If the cable gets damaged, switch off the unit
and have it changed only by professionally qualified personnel. If changing the electric power cable,
use only “HAR H05 VV-F” 3x0.75 mm2cable with a maximum outside diameter of 8 mm.
Acces to the electrical terminal board
Follow the instructions given in fig. 8 to access the electrical connection terminal board (fig. 8). The layout
of the terminals for the various connections is given in the wiring diagram in the diagram fig. 9.
2.6 Flue system
The unit is “type C” with a sealed chamber and forced draught, the air inlet and flue outlet must be
connected to one of the following flue systems. With the aid of the tables and methods of calculation indi-
cated, before commencing installation, it is first necessary to check that the flue system does not exceed
the maximum permissible length. The current standards and local regulations must be observed.
It should be notes that only Ferroli flue system and accessories should be used on this appliance,
as per BS 5440 2000 and C.E. test certification.

Optimax 25 S
16
* = between
10 e 60 mm
* = between
10 e 60 mm
80
Standard 1KWMA53A
Flue kit
215 185
Install level
Install level
50*110
95
80
30 50*
30
95
S 50*
P
110
L
DS
P
125
S
30
95
DS50*
L
30
95
215 185
175
185215
175
Install level
Install level
Connection with concentric flue system
The unit can be connected to a concentric air/flue duct with a wall or rooftop outlet as shown on the
following drawings. Numerous accessories are available on request to meet the various installation
requirements. Please refer to our “flue manual” or the price list.
Standard concentric flue installation
Side view
View from above
fig. 10a
Side Outlet
fig. 10b
Front view
View from above
P = S + 160 mm
Rear Outlet
L = S + D + 170 mm
Horizontal flue installation
1. Define the position for installing the unit.
2. If using standard flue (1KWMA53A) this must be installed level, for non-standard flue lenghts over 1
Mtr a fall of 3 mm per metre should be incorporated.
3. Make a hole of diameter 10 - 20 mm greater than the nominal diameter of the concentric pipe
used.
4. If necessary, cut the end pipe to size, ensuring that the external pipe protrudes from the wall by
between 10 and 60 mm (fig. 10a and 10b). Remove the cutting burrs.
5. Connect the flue to the boiler, positioning the seals correctly. Seal the flue into the wall with silicone
or sand + cement and cover with wall seals provided.
Flue seals should be lubricated with a silicone type grease to prevent damage (grease not sup-
plied)

Optimax 25 S
17
Angled roof tile
1KWMA82U
1KWMA56U
950
50
1KWMA71W
max. 6 metres 60/100
Roof end piece
1KWMA83U
68
215 185
max. 16 metres 80/125
95050
50 950
50
1000 125
10
fig. 10c
Reduction factors for bends
1 m
0,5 m
0,5 m
0,25 m
Table 2b
Maximum permissible
duct length (Horizontal)
Ø mm
60/100
5 m* 15 m
Ø mm
80/125
Table 2a
Maximum permissible
duct length (Vertical) 6 m* 16 m
The total length in equivalent metres of the concentric flue must not exceed the maximum lengths stated
in the following table, note that each bend gives rise to the stated reduction. For example, a duct =
60/100 composed of 1 bend of 90° +1 horizontal metre + 2 bends of 45° + 1 horizontal metre has a
total equivalent length of 4 metres.
Vertical flueing
The installation of a concentric vertical flue can be carried out as follows,
Install the appliance as previously mentioned in this manual.
1. Connect onto the flue assembly at the top of the appliance a concentric vertical adaptor part number
1KWMA71W,
2. Use the required amount of 1mtr flue extensions (part number 1KWMA56U) inserting them spigot
down ensuring the seals are well lubricated with silicone grease (not supplied) and correctly located
into the sockets.
3. If required 45°bends (Part number1KWMA64A)
may be used with a resistance value of 0.5mtrs
each, the flue should be routed in such away
to avoid any unnecessary deviation and thus
minimise the amount of bends required.
4. The termination should be made through
our concentric flue outlet (part number
1KWMA83U) in conjunction with a roof slate
pitched (part number 1KWMA82U)or flat roof
(part number 1KWMA81U) The storm collar
must be fixed on using the three screws provi-
ded and sealed with an external grade silicone
(not supplied).
5. For longer flue lengths a 125mm concentric
flue system is available.
6. All flue installations must comply with BS5440
part 1 and must only be of Fèrroli manufacture.
The vertical flue must continually rise and be
supported throughout its length. The flue
must be inspected whilst commissioning the
appliance to ensure it is sound throughout its
length.
This information is for guidance purposes and
Fèrroli will in no way be held responsible for
incorrect installation following this guide.
Vertical Outlet

Optimax 25 S
18
4
5
1KWMA83W
1KWMA82U
1KWMA84U
1KWMR54A
2
Ref.
2
4
5
23
23
1
Vertical air pipe Ø80
Vertical flue pipe Ø80
80 Ø vertical flue Kit
Description Equivalent
loss
23,0 m
36,8 m
12,0 m
71,8 m
Total
Table 3
fig. 11
fig. 12
Connection with 80 mm pipe system
The unit can be connected to a system of sepa-
rate air/flue ducts for a wall or rooftop outlet
as shown on the drawings 11 - 12 alongside.
Numerous accessories are available on request
to meet the various installation requirements.
The components used most frequently are
stated in tables 4 - 5. Please refer to the flue
accessory catalogue or the price list for addi-
tional components.
To check you do not exceed the maximum per-
missible duct length, it is necessary to make a
simple calculation before installation:
1. For each component, tables 4 - 5 provide
an “equivalent load loss in linear metres”,
depending on the position of installation
of the component (with air suction or flue
extraction, vertical or horizontal).
The loss is called “equivalent in linear metres”
since it is compared to the loss of one metre
of duct in air suction (defined as equal to 1).
For example, a bend at 90° of Ø80 in flue
extraction has an equivalent loss of 2.5 linear
metres, i.e. it has a loss equal to that of 2.5
linear metres of duct in air suction.
2. After defining the layout of the system of
split flues, add up the losses in equivalent
metres, dependingon the installation position,
of all the components and accessories in the
system.
3. Check that the total calculated loss is less
than or equal to 75 equivalent metres, i.e.
the maximum permissible for this model of
boiler.
120 120 65
95
175
370
Ø80
AIR
Ø80
FUMES
Remove
the closing
cap
KWMR54A
80 84 80

Optimax 25 S
19
Table of flue and accessory
KWMA86A
KWMA85A
KWMA84U
Air Flue
Vertical Horizontal Vertical Horizontal
KWMA65W
KWMA01W
KWMA83W • 1,00 m
Description
Pipe Ø 80
male-female
Bend 45°Ø 80 mm
male - female
Bend 90°Ø 80 mm
male - female
Description
Horozontial
flue terminal
Horozontial
air terminal
Vertical flue
terminal
1 1 1.6 2
1.2 1.8
1.5 2.0
Equivalent losses in
metres (linear)
5
2
Air Flue
Vertical Horizontal Vertical Horizontal
Equivalent losses in
metres (linear)
12
Accessories Ø 80 Accessories Ø 80
Table 4 Table 5
The stated loss values refer to genuine Ferroli flue accessories.
Terminal Position
P
D, E
Q
Q
l
BC
A
G
F
L
J
HH
K
N
N
MM
Q
fig. 13

Optimax 25 S
20
Minimum Dimensions of Flue Terminal Positions
Directly below an opening, air brick,
opening windows, etc.
Above an opening, air brick,
opening windows, etc.
Horizontally to an opening, air brick,
opening windows, etc.
Below gutters, soil pipes or drain pipes
Below balconies or car port roof
Below eaves
From a vertical drain pipe or soil pipe
From an internal or external corner
From a surface facing the terminal
From a terminal facing the terminal
From the wall on which the terminal is mounted
From a vertical structure on the roof
Above intersection with roof
Horizontally from a terminal on the same wall
Vertically from a terminal on the same wall
From an opening in the car port (e.g. door,
window) into the dwelling
Above ground roof or balcony level
300mm
300mm
300mm
200mm
75mm
200mm
150mm
100mm
300mm
600mm
300mm
300mm
150mm
1200mm
1200mm
1500mm
N/A
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
NOTE
N/A = Not applicable
In addition, the terminal should not be nearer than 150mm (fanned draugt) or
300mm (natural draugt) to an opening in the building fabric formed for the purpose
of accommodating a built-in element such as a window frame.
Condensing Terminal Positions: If the flue is to be terminated at low level, then the
potential effect of the plume must be considered.
The plume should not be directed: across a frequently used access route
across a neighbouring property
towards a window or door