Ferroli OPTIMAX 25 OV Troubleshooting guide

OPTIMAX 25 OV
wall-mounting,
pre-mixed
condensing gas boiler
INSTRUCTIONS FOR USE INSTALLATION AND MAINTENANCE
cod. 3544708/3 - 08/2004

Optimax 25 OV
2
IMPORTANT
Your “benchmark” Installation, Commissioning and Service Record Log Book will be enclosed in
your customer information pack.
“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 arecomplete
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. Carefully
follow these instructions in order to avoid danger and damage to persons, and or
property.
This symbols calls attention to a note or an important notice for the installer/service
engineer.
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)
President and Legal Representative
Cav. del Lavoro
Dante Ferroli

Optimax 25 OV
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..............................................................................13
2.5 Electrical Connections ..........................................................................................13
2.6 Flue system ...........................................................................................................16
2.7 Condensate outlet connection .............................................................................22
3. SERVICE AND MAINTENANCE............................................................24
3.1 Adjustments ..........................................................................................................24
3.2 System start-up.....................................................................................................25
3.3 Maintenance..........................................................................................................26
3.4 Troubleshooting ....................................................................................................28
4 TECHNICAL CHARACTERISTICS AND DATA.........................................30
4.1 Dimensions and connections ................................................................................30
4.2 General view and main components ....................................................................31
4.3 Hydraulic diagram.................................................................................................32
4.4 Technical data table ..............................................................................................33
4.5 Wiring diagram .....................................................................................................34

4
Optimax 25 OV
1. OPERATING INSTRUCTIONS
1.1 Introduction
Dear Customer,
Thank you for choosing Optimax 25 OV, a FERROLI wall-mounted boiler of the latest generation, fea-
turing advanced design and cutting-edge technology.
Optimax 25 OV 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 ceramic surface pre-mix burner, equipped 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, safety valve, temperature
sensors, a safety thermostat and a flue gas 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.
The user only has to set the temperature desired inside the home (by means of a room thermostat and
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 OV
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 lock-out.
Pressing the key 3 times within 3 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, burner flame
established (point at bottom lights up) or should a fault occur the appropriate code will appear within
the display.

6
Optimax 25 OV
1.4 Adjustments
Room temperature adjustment (Via room thermostat )
Using the room thermostat, set the temperature desired in the room. 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, it will re-light when the room
temperature falls below the setpoint level, providing there is still a demand from the time clock.
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
flashes and once defined it stops flashing after 2 sec. and reverts 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 active.
Turning it onto (Winter) turns on heating, via the time clock and room thermostat.
If the boiler is also used for hot water production do not select the summer position as this will
disable both heating and hot water modes.
1.3 Turning ON and OFF
Ignition
• Open the gas isolation valve on the boiler.
• Purge the gas supply taking the necessary precautions.
• Turn on the electrical switch at the 3amp switched fused spur.
• 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 printed circuit board is still powered, heating operation
is disabled and the display appears the frost protection will remain active.
Close the gas isolation valve under 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 OV
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 operational faults, 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 a problem with the boiler,
or system the display will show the fault code. There are some faults that will require the end user to
press RESET (2 - fig. 1); if the boiler fails to start, It is necessary to rectify the fault indicated by the
LED display (faults from 1 to 26); 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 46).
Example
Boiler failed to light
Make sure that the gas isolation valve on the boiler and on the
gas meter are open.
Press the RESET button (2 Fig. 1).
Fault CureDISPLAY
Before calling the FERROLI Caresafe helpline, check that the problem is not due to there being
no gas or electricity, and that all external controls are wired correctly and calling fo heat.
If the problem remains after two attempts at resetting, contact your nearest FERROLI Caresafe.
For other faults, refer to section 3.4 “Troubleshooting”.

Optimax 25 OV
8
2. INSTALLATION
2.1 General Instructions
This device must only be used for the purpose for which it is specially designed. This unit is desi-
gned to heat water to a temperature below boiling point and must be connected to a heating
system and, 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
COMPEDENT 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 OV
9
> 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
DC
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 design 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.

Optimax 25 OV
10
fig. 3
50
50 45
35
2
1 4
3
95 120 185
164
400
201 35
50 35
110,5
2.3 Water connections
The heating capacityof the unit shouldbe previouslyestablished
by calculating the building’s heat requirement according to
current regulations. For good operation and long life of the
boiler, the plumbing 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 plug at the lowest point in
the system to allow its complete emptying, when required.
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, thoroughly clean all the pipes of the system
to remove residues or impurities that could affect the unit’s
operation. Flush system in accordance with BS 7593.
Make the connections to the corresponding tappings as shown
in fig. 3.
Key
1 CH flow (22 mm with compression coupler fitted)
2 Gas inlet (22 mm with isolation valve)
3 Condense outlet
4 CH return (22 mm with compression coupler fitted)
It is advisable to install anti-tamper isolation valves between the boiler and heating system allowing
the boiler to be isolated from the system if necessary.

Optimax 25 OV
11
The connecting kits shown in fig. 4 are supplied as standard.
Key
A = Nut
B = Compression olive
C = Nipple
F = 1/2 gas seal - Blue
Gas isolation valve
AB
F
A
22
mm
22
mm
ACBB
X2
X1
Flow
Return
Appliance
drain OFF valve
fig. 4
Make Up Water
This appliance is designed to work on an open vented fully pumped heating system only, (see fig 5 page
12). The make up of water must be made via a suitably sized cold feed and expansion tank installed to
the current regulations.
This appliance is not suitable for gravity type installations or primatic type cylinders only indirect ones
should be used.
The system must be fully pumped due to the complex design of the Alluminium Laminar heat exchang-
ers high efficiency design.
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.

Optimax 25 OV
12
To DHW taps
Static Head
min. 2 m
max. 150 mm
Isolating valve
Drain
Flow
Return
Open
Vent Open
Vent
Motorised valve
22 mm
DHW
Isolating
valve
CH Pump
Automatic By-pass
Motorised valve
22 mm CH Radiator Radiator
Balancing
valve
15 mm
22 mm
Indirect cylinder
Indirect coil missing
Schematic layout for fully pumped heating and hot water.
Fig. 5

Optimax 25 OV
13
Water treatment
When treatment is used ferroli limited recommend 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 combination 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 checking
gas rate. Gas pressures should be checked after 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 cross sectional area of the system’s cable is suitable for the power
absorbed by the unit.
The boiler is prewired and provided with a cable for connection to the electricity supply. The connec-
tions 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 supply. It is important to respect the polarities (LIVE: brown wire / NEUTRAL: blue wire / EARTH:
yellow-green wire) when connecting to the electrical supply.

Optimax 25 OV
14
Central heating request
The heat demand can be done by the room thermostat (terminal 4-5) or by a switch line phase 230 V
(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
Balancing
valve
C.H.
Zone Valve
Automatic
bypass
(mimimum flow of 6l/min.)
A.A.V
A.A.V
DHW
zone
valve
*Note: cold feed and expansion
not shown for clarity
(see fig. 5)
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 Volt A/C
fused at
3 amps
BROWN BLUE
GREY ORANGE
L
765
8
Fig. 6a
Fig. 6b
Remove
connection
between
terminals 4-5

Optimax 25 OV
15
Optimax “Y” Plan
Pipe layout
Auto air vent
Automatic
bypass
(mimimum flow of 6LTR/min.)
OPTIMAX
FERROLI
BOILER Balancing
valve
A.A.V
A.A.V
*Note: cold feed and expansion
not shown for clarity
(see fig. 5)
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 Volt A/C
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
765
8
fig. 7a
fig. 7b
Remove
connection
between
terminals 4-5

Optimax 25 OV
16
fig. 8
System external
controls
7
6
5
4
3
2
1
Switch Line 230V
External
pump
N
L
230 V
8
fig. 9
Room thermostat
REMOVE CONNECTIONS 4 - 5 IF EXTERNAL
CONTROL FITTED.
WARNING: the room thermostat works at
230V.
The user must never change the unit’s power cable. If the cable gets damaged, switch off the
unit and have it changed solely 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.
Access to the electrical terminal board
To access boiler electrical connections remove the screw and drop down electrical cover (fig. 8). The
layout of the terminals for the various connections is given in the wiring diagram in fig 9 below.
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 noted that only Ferroli flue system and accessories should be used on this appliance,
as per BS 5440 2000 and C.E. test certification.
External Pump
The external pump must be connected to ter-
minals 5, 6 (earth) and 7 of the terminal block
(fig. 9), to allow the pump over-run circuit to
operate.

Optimax 25 OV
17
* = between
10 e 60 mm
* = between
10 e 60 mm
25
95
Standard 1KWMR53A
Flue kit
50*
30
S50*
P
L
DS
P
125
S
30
95 D
S
50*
L
30
95
80
50* 30 95
215 185
80
215 185
90
Drill the wall 10 ÷20 mm
more than the pipe diameter
185215
90
Drill the wall 10 ÷20 mm
more than the pipe diameter
Install level
Install level Install level
Install level
Standard 1KWMR53A
Flue kit
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 + 205 mm
Horizontal flue installation
1. Define the position for installing the unit.
2. If using standard flue (1KWMR53A) this must be installed level, for non-standard flue lenghts over
1mtr 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.
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

Optimax 25 OV
18
Angled roof tile
1KWMA82U
1KWMA56U
950
50
1KWMA71W
max. 6 mt 60/100
Roof end piece
1KWMA83U
68
95050
50 950
50
1000 125
10
max. 12 mt 80/125
Vertical Outlet
fig. 10c
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)
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 12 m
Ø mm
80/125
Table 2a
Maximum permissible
duct length (Vertical) 6 m 12 m
For the installation:
1. Define the position for installing the unit.
2. Drill the wall for the air/flue pipe outlet accor-
ding to the references stated in the table,
considering that the horizontal sections of
piping must have a gradient of approxima-
tely 3 mm per metre of length downwards
to prevent any rainwater getting into the
boiler.
3. Make a hole of diameter 10 - 20 mm greater
than the nominal diameter of the coaxial pipe
used to facilitate insertion.
4. If necessary, cut the end pipe to size, consi-
dering that the external pipe must protrude
from the wall by between 10 and 60 mm (Fig.
10a and 10b). Eliminate the cutting burrs and
lubrificate seals.
5. Connect the ducts to the boiler, positioning
the gaskets correctly and seal the wall cou-
pling points with special sleeves.
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.

Optimax 25 OV
19
1KWMR54A
4
2 1
3
Ref.
1
2
3
4
21
25
1
2
Vertical flue pipe Ø80
Vertical air pipe Ø80
Vertical outlet terminal
Kit (1KWMR54A)
Description Equivalent
loss
33,6 m
25,0 m
12,0 m
0,6 m
71,2 m
Total
Table 3
fig. 11
fig. 12
Ø80
AIR
Ø80
FUMES
Remove
the closing
cap
KWMR54A
95 120 185
80 84
90
274
Connection with 80 mm pipe system
The unit can be connected to a system of sepa-
rate air/fume 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
manual or the price list for additional compo-
nents.
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 completely defining the layout of the
two pipe flue system, add up the losses in
equivalent metres, depending on the instal-
lation 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.
If the chosen flue system exceeds the
maximum permissible limit, it is recom-
mended to use ducts with a larger dia-
meter for some sections.

Optimax 25 OV
20
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
111.62
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