Ferroli Divatop ST F 24 Manual

Appr. nr. B98.01 A - CE 0063 AT 4967
FERROLI F24
INSTALLATION, SERVICE AND USER
INSTRUCTIONS
G.C. NO: 47-267-31
3544015/0 - 07/2002
Gas Combination Boiler for Central Heating
andHot Water Production,Wall Mounted,
Copper Heat Exchanger,Fan Assisted,
Room Sealed,
Electronic Flame Ignition andControl

FERROLI F24
2
CE MARK
CE mark documents that the Ferroli gas appliances comply with the requirement contained in
European directives applicable to them.
In particular, the appliances comply with the following CEE directives and the technical specifications
provided from them:
• Gas appliances directive 90/396
• Efficiencies directive 92/42
• Low tension directive 73/23 (modified from the 93/68)
• Electromagnetic compatibility directive 89/396 (modified from the 93/68)
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"
"All CORGI Registered Installers carry aCORGI ID card and have aregistration number. Both
should be recorded in your central heating log book. You can check to the CORGI register
by calling CORGI on 01256 372300".
Ferroliisamember oftheBenchmarkinitiativeand fullysupportstheaimsof theprogramme.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.
INDE
1 DESCRIPTION
2TECHNICAL AND DIMENSIONAL CHARACTERISTICS 4
INSTALLATIN DETAILS
4COMMISSIONIN AND TESTIN 26
ADUSTMENT AND ASCONVERSION 2
6MAINTENANCE AND CLEANIN 2
REPLACEMENTPARTS 1
AULTINDIN 6
ELECTRICAL AND NCTINAL SCHEME4
1USERINSTRCTINS4

FERROLI F24
3
1 DESCRIPTION
1.01 Introduction
The Ferroli F24 is definedas a“room sealed” combination boiler, all air requiredfor combustion is takenfrom
outsidetheroominwhichitisinstalled.Itisanewhighperformancegasfiredheatgeneratorforcentralheatingand
domestichotwaterproduction.Aspecialfeatureofthis boilerisitsbuilt-inelectronicflame ignitionandcontrolunit
making burneroperation completely automatic and safe.The main components are as follows:
•Copperheat exchangerconsisting of three finnedtubesspecifically shapedfor high efficiency.
•There are three coppercoils insertedin the three heating circuit tubes. These represent the domestic
hot waterheat exchanger. Their shape and high exchange surface areaenable the full output of the
boilerto be absorbed.
•Ceramic fibre insulatedcombustion chamber
•12 stainless steelbladedburners specifically designedfor this boiler.
•Fan for discharge of combustion products and intake of combustion air.
•Differential air pressure switch.For safety reasons, this ensuresthe burnerignitesonly whenthe fan is functioning
correctly.
•Hermetically sealedcompartment made from corrosion-resistant steelenclosing the above components.
•Combination gas safety valve with modulator, complete with pressure stabiliser.
•Flowmetergiving the domestic hot watercircuit precedence overthe central heating circuit.
•Pressure reliefvalve for the central heating circuit setto openat 3bar.
•Built-in Expansion vessel.
•Variable speedpump.
•Central heating flow temperature adjustment thermostat.
•Domestic hot waterflow temperature adjustment thermostat.
•Central heating limit thermostat.
•Overheat safety thermostat.
•Electronic control unit for automatic flame ignition and control.
•Central heating low waterpressure cut off switch.
•Domestic hot waterflow temperature sensor.
•Central heating flow temperature sensor.
1.02Instructionsand regulations
Assembly,installation, firststartup andmaintenance mustbecarriedout bycompetentpersons only,in accordance
with all current technical regulations and directives.
OSHH
Materials usedin the manufacture of this appliance are non hazardous and no special precautions are
requiredwhenservicing.
Related Documents
Thisappliancemust beinstalled strictlyin accordancewiththeseinstructions.
The Gas Safety Regulations (Installations &Use)1996.
The Local Building Regulations.
The Building Regulations.
The Buildings Standards (Scotland -Consolidated)Regulations.
British Standards Codesof Practice:
B.S.75931992TREATMENT OF WATERINDOMESTIC HOT WATERCENTRALHEATING SYSTEMS
B.S.5546 1990 INSTALLATIONOF HOT WATERSUPPLIESFORDOMESTIC PURPOSES
B.S.5440 Part 12000 FLUES
B.S.5440 Part 21989 AIRSUPPLY
B.S.5449 1990 FORCED CIRCULATIONHOT WATERSYSTEMS
B.S.6798 1987 INSTALLATIONOF GASFIRED HOT WATERBOILERS
B.S.68911989 GASINSTALLATIONS
B.S.76711992IEE WIRING REGULATIONS
B.S.48141990 SPECIFICATIONFOREXPANSIONVESSELS
B.S.54821994 INSTALLATIONOF LPG
ModelWaterBye Laws
For Northern Ireland the rulesin force apply

FERROLI F24
4
Fig. 1
Top view
Distance between connections
178
190 270
Bottom view
272
760
249
98
609536 60 95
460
100
727
114
160100 25 150 25
84
80 80
12070 120 150
110
5
34
2
1
2TECHNICAL AND DIMENSIONAL CHARACTERISTICS
2.01 Technical information
Ferroli F24 boilers are central heating and domestichot water heat generators and are produced as
standard to function with natural gas or LiquidPetrolium Gas converted appliances.
Key
1 -3/4"central heating flow outlet
2-1/2"domestichot water flow outlet
3-3/4“gas inlet
4 -1/2"domestichot water inlet
5-3/4"central heating return inlet
6-Pressure relief outlet

FERROLI F24
5
N.B. - The gas pressures at the burner and gas flows during the central heating phase given in the table refer
to nominal boiler output.To reduce this output (where necessary), gas pressure must be reduced untilthe
required output levelis reached (see figures 4and 5).
During domestic hotwater production,gas pressures to the burner must correspondtothe maximum
outputgiven in table forthe type ofgas.
Gas pressure must beadjustedduring maximum draw-off ofdomestic hotwater.
•Maximum working temperature forcentral heating flow:85°C
•Maximum temperature ofdomestic hotwater:55°C, adjustable between 40°C and55°C.
•Minimum domestic coldwater pressure requiredfor95%heat input:
- Flowrestrictorfitted(standard)- 1,2 bar;
- Flowrestrictorremoved- 0,5bar
MODEL Heat output Heat input Domestic hot
water output Boiler water contents Domestic hot water contents
kW kW kW kW kW Litres Litres
Ferroli F24 23,8 9,7 25,8 11,5 23,8 1,5 0,8
MODEL
Connections Expansion vessel Max. working
pressure
central
heating
circuit
Max.
working
pressure hot
water circuit
12345Capacity Pre-pressurising
value
Ø Ø Ø Ø Ø Litres bar bar bar
Ferroli F24 3/4” 1/2” 3/4” 1/2” 3/4” 7 1 3 6
MODEL Main injectors (mm) Gas flow rates to main burners
for central heating Gas valve
Ø1/2
G20 - NG G31 -LPG G20 - NG G31 -LPG
ØØ m
3
/h kg/h
Ferroli F24 12x1,30 12x0,77 2,73 2,00 H. V K4105G
MODEL
Gas supply pressures
working Gas pressure at main burner for central heating Safety valve
G20 G31 G20 G31
min. m min. m
mbar mbar mbar mbar mbar mbar bar
Ferroli F24 20 37 2,5 11,8 7,8 36,0
MODEL
Domestic hot
water production
with ∆t 30 °C
Domestic hot
water production
with ∆t 35 °C
Max. working
pressure domestic
hot water Protection
level Weight
G20 G31
l/min. l/min. mbar mbar kg
Ferroli F24 11,3 9,7 11,8 36,0 IP44 38
TechnicalData

FERROLI F24
6
2.03 Boiler water flow diagram
OUT
IN
MIN
AIR
IN
AIR
IN
FLUE
OUT
C.H.
OUT D.H.W. OUT GAS IN D.H.W. IN C.H. IN
Fig. 3
2.02 Boiler maincomponents
Key
5Room sealed compartment
7Gas inlet
8Domestichot water outlet
9Domestichot water inlet
10 Central heating flowoutlet
11 Central heating return inlet
14Safetyvalve
16Fan
19Combustion chamber
20 Burner assembly
21Maininjector
22 Burner
26Combustion chamber insulation
27Copper heat exchanger for central heating and
domestichot water
28Fluecollector from heat exchanger
32 Central heating pump
34Central heating flowtemperature sensor
36Automaticairvent valve
42 Domestichot water flow
temperature sensor
Fig. 2
43
16
27
50
19
49
28
5
20
21
26
132
90 91
818222
56
IN OUT
MIN
RESET
OFF
ON
05
1234
6
bar
98 63 157 145
°C°C
62
10 8 784 85 44 136
32
36
114
34
14 42 9 11
43 Airpressure switch
44 Gas valve
49Safetyoverheat thermostat
50 Central heating flowlimitthermostat
56Expansion vessel
62 Time clock
63Central heating temperature adjustment
81Ignition electrode
82Sensor electrode
84Primarygas valvesolenoid
85Secondarygas valvesolenoid
90*Fluesampling point
91*Airsampling point
98On/Off/Reset switch
114Lowwater pressure cutoff switch
132 Fluegas deflector
136Flowmeter
145Central heating pressure gauge
157Domestichot water temperature adjustment
*For use withfluegas analysisequipment

FERROLI F24
7
2.04 Central heating adjustment (not normally required)
To adjust boiler heat input (thusalso regulatingheat output to the central heatingwater) simply adjust the main
burner via the electroniccontrol board (fig. 4and 5and see paragraph 5.04 page 29).
The diagramsindicate the variation in heat output to the water asburner workingpressure isvaried.
Adjustingboiler output to the actual requirementsofthe central heatingsystem will minimise boiler
cyclingthussavingfuel,varyingthe output hasvirtually no effect on the efficiency and combustion
characteristics ofthe boiler.
Diagram of pressures
and outputs with Natural gas
Fig. 4Fig. 5
Diagram of pressures and outputs
with LPG (Propane)
2
3
4
5
6
7
8
9
10
11
12
13
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
8 9 10 11 12 13 14 15 16 17 18 19 20 21
kW
kcal/h
x 1000
mbar
14
kW
kcal/h
X 1000
m
b
ar
18 19 20 21 22 23
5
10
15
20
25
30
35
9 1011121314151617
91011121314 18192015 16 178
2.05Domestichot water variabilitycharacteristics
The temperature ofthe domestichot water can
be varied from 40 to 55°C by adjustingthe boiler
potentiometer.
Diagram of domestichot water production
0 345678910111213141516
39
40
45
50
55
60
65
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Temperature of domestichot water intake 15°C
Flow of domestichot water l/min
Temperature of domestichot water supply°C
Boiler output exchanged kcal/1000
Fig. 6

FERROLI F24
8
Fig. 8
Pressure loss diagram
SIZING OF ADDITIONAL EXPANSION VESSELS:
Deduct from the value given inthe table the 8litre
vessel supplied.
Note:
1. Fill C.H. installation to min. 1.5bar.
2.Expansion vessel must be fitted to central heating
return pipe.
3.The standard 7litre expansion vessel ischarged
to 1bar.
4.The additional expansion vessel should be charged
to 1bar.
SAFETYVALVE
SETTING (bar)
VESSEL CHARGE
PRESSURE(bar)
INITIAL SYSTEM
PRESSURE(bar)
TOTAL WATER
CONTENT ofSYSTEM
3.0
0.51.01.5
1.01.52.01.52.02.0
EXPANSION VESSEL VOLUME(litres)
LITRES
253.56.513.74.710.38.3
507.012.927.59.520.616.5
7510.519.441.314.230.924.8
100 14.025.955.119.041.233.1
12517.532.468.923.751.541.3
15021.038.882.628.561.849.6
17524.545.396.433.272.157.9
200 28.051.8110.238.082.466.2
0.1400.2590.551 0.1900.4120.33
For syst.volumes other than
those givenabove,mult.the syst.
volume bythe factor across
m |h
3
Q
8
7
6
5
4
3
2
1
00.5 1.5 2.512
H
mbar x 100
2.06 Pumpcharacteristics
The pump head available for circulating the water isgiven
infig. 7.
N.B.-The pump isfactoryset at position 3. The pump isa
Grundfos type 15-50UPSseries.
Grundfos Pumpper formance graph
Note -Minimum flowthroughboiler heat exchanger at any
time should not fall below6litres per minute.
Ifthe total volume of water inthe system exceeds 40litres
an additional expansion vessel must be fitted to the central
heating return pipe.
Fig. 7
123Speed settings
ABoilers pressure drop
BAvailable pump head C.H.

FERROLI F24
9
3 INSTALLATIONDETAILS
Gas Safety (Installation & Use) Regulations: 1996
In the interest of safety, it is the lawthat all gas appliances are installedby a competent person in accordance
with the above Regulations, BuildingRegulations/BuildingStandards Scotland, Codes of Practice, current I.E.E.
Regulations andthe byelaws of the LocalWater Undertaking. Failure to comply withthe Regulations may leadto
prosecution;it is yourresponsibility to ensure that the lawis compliedwith.
N.B.For Northern Irelandthe rules in force apply.
Important-If theboiler isto befittedina timberframedbuildingit shouldbefittedin accordancewiththeInstituteof
Gas Engineers document IGE/UP/7.If in doubt advice should be sought fromthe LocalSupplier.
Location of Boiler
The installation of the Ferroli F24 must be on a suitable non-combustible loadbearingwall which will provide
an adequate fixingfor the boiler mountingbracket assembly.The location should be in an area where
the water pipes will not be subjectedto frost conditions.In sitingthe combination boiler the following
limitations must be observed:
The combination boiler may be installedin any roomor internalspace, although particular attention is drawn
to the requirements of the current I.E.E. wiringregulations andin Scotlandthe electricalprovisions of the
buildingregulations applicable in Scotland, with respect to the installation of the combination boiler in a room
or internalspace containinga bath or shower.
Where a roomsealedappliance is installedin a roomcontaininga bath or shower any electricalswitch
or appliance controlutilisingmains electricity must be situatedso that it cannot be touchedby a person
usingthe bath or shower.
AirSupply
The roomor compartment in which the boiler is installeddoes not require a purpose providedvent when
usingthe standardconcentricflue.
Flue System
The boiler allows the flue outlet to be taken fromthe rear of the boiler, fromeither side or vertically.
Astandardflue length of 0.75metres is provided. Alternative lengths of two or three metres can be supplied
(equivalent to wall thicknesses of up to 565, 1815 and2815mm for rear flues, deduct 91mm plus distance fromside
wall for side outlet flues).It is absolutely essential, to ensure that products of combustion discharging fromthe
terminal cannot re-enterthe building,orenterany adjacent building,throughventilations,windows,doors,
natural airinfiltration orforcedventilation/airconditioning.
Gas Supply
If necessary the localGas supplier should be consulted, at the installation planningstage, in order to establish
the availability of an adequate supply of gas.
An existingservice pipe must not be usedwithout prior consultation with the LocalGas supplier.
Agas meter can only be connectedby the LocalGas supplier, or by a LocalGas suppliers Contractor.
Installation pipes should be fittedin accordance with BS6891-1988.
Appliance inlet workingpressure must be 20mbar MINIMUM, for NGand37mbar minimum for LPG.
Pipeworkfromthe meter to the combination boiler must be of an adequate size.
The boiler requires 2.73m3/h of naturalgas, and2,00 kg/h of LPG.
Do not use pipes of a smaller size than the combination boiler inlet gas connection.
The complete installation must be testedfor gas soundness andpurgedas describedin BS6981-1988.All pipework
must be adequately supported. An isolatinggas valve is providedandshould be fittedon the boiler gas inlet.
Please wait 10 minutes when lightingfromcold before checkinggas rate.Gas pressures shouldbe checkedafter
the boilerhas operatedfor10minutes to reachthermal equilibrium.
WaterSystem
Note -the boileris designedforsealedsystems only andmust NOT be usedon open ventedsystems.

FERROLI F24
10
Fig. 9
Central Heating
Detailed recommendations are given inBS6798, BS5449,BS6700 and CP342 Part 2. Pipework not forming part of
the useful heating surface should be insulated to prevent any heat losses or possible freezing (i.e. inroof spaces
or ventilated underfloor spaces). Draintaps should be positioned at the lowest point of the system inaccessible
locations to permitthe whole system to be drained down. The draintaps should be inaccordance with
BS2879. Copper tubing to BS2871,Part 1isrecommended for water carrying pipework. Pipework in
horizontal runs should have agradient where possible to facilitate the removal of air. Ensure that the
boiler heat exchanger isnot anatural point for aircollection. Atypical heating system with domestic
hot water circuitisillustrated infig. 9.
Important -Ifthermostaticradiator vales are fitted a bypass must be fittedtoensure a minimumflowrate through
the boiler of6l/min. The bypass should be fitted as far as possible from the boiler.
Make UpWater
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 chargeand pressurise the system
directly, isconditional upon the Local Water Byelaws. Againany such connection must be disconnected after use.
Atypical temporary filling loop isshown infig. 10.
DomesticHot Water
Always fitascale reducer in"hard water areas"(18clarke degrees or over)". A15mm copper connection point
on the boiler for attaching to the mainsupply isprovided. The maximum domesticwater pressure for the
inlet supply is10 bar (145 P.S.I.). Ifthe coldmainssupplyexceeds 5bar (72 P.S.I.), a water governor
or pressure reducing valve must be fittedby the installer into the mains supply inan inconspicuous but
accessible position preferable between 3and 5metres (10-16ft) before the appliance. Such avalve must
be approved by the Water Research Council.
Attention -isdrawn to the Model Water Byelaws.
Fittingsmanufactured from duplex (alpha-beta) brass are
not acceptable for underground use and certainwater
undertakingswill not accept theiruse above ground.
Ensure all pipework isadequately supported
NOTE: Abypass that will ensure aminimum flow rate of
6l/min. at all all time must be fitted as far as possible
from the boiler ifthermostaticradiator valves are fitted
thoughout.
Gas
Cold water Additional expansion
vessel C.H.
Filling
point C.H.
Bypass
Fig. 10
Key
1.Filling point C.H.
2. Temporary connection
3.Cold water supply

FERROLI F24
11
CLEARANCES:
* 600mm minimum clearance for servicing
access
Top clearance only applies to 100Ø concentric
flue system
460 5 min.5 min.
100 min.900
200 min.
272 50 mm
600* min.
760
Fig.11
Terminal Position
Fig.12
P
D, E
Q
Q
l
BC
A
G
F
L
J
HH
K
N
N
MM
Q
Directly below an opening, air brick, (0-7 kW)
opening windows, etc. (>7-14 kW)
(>14-32 kW)
(>32-70 kW)
Above an opening, air brick, (0-7 kW)
opening windows, etc. (>7-14 kW)
(>14-32 kW)
(>32-70 kW)
Horizontally to an opening, air brick, (0-7 kW)
opening windows, etc. (>7-14 kW)
(>14-32 kW)
(>32-70 kW)
Below gutters, soil pipes or drain pipes
Below eaves
Below balconies or car port roof
From a vertical drain pipe or soil pipe
From an internal or external corner
Above ground roof or balcony level
From a surface facing the terminal
(also see 6.1.2)
From a terminal facing the terminal
From an opening in the car port ( e.g. door,
window) into the dwelling
Vertically from a terminal on the same wall
Horizontally from a terminal on the same wall
From the wall on which the terminal is mounted
From a vertical structure on the roof
Above intersection with roof
Dimensions Terminal position
(kW input expressed in net)
Balanced flues room
sealed Open flues
Natural
draught Natural draught
Fanned
draught Fanned draught
Aa300 mm
600 mm
1500 mm
2000 mm
300 mm Not allowed 300 mm
Ba300 mm
300 mm
300 mm
600 mm
300 mm Not allowed 300 mm
Ca300 mm
400 mm
600 mm
600 mm
300 mm Not allowed 300 mm
D300 mm 75 mm Not allowed 75 mm
E300 mm 200 mm Not allowed 200 mm
F600 mm 200 mm Not allowed 200 mm
G300 mm 150 mmbNot allowed 150 mm
H600 mm 300 mm Not allowed 200 mm
I300 mm 300 mm Not allowed 300 mm
J600 mm 600 mm N/A 600 mm
K600 mm 1200 mm N/A 1200 mm
L1200 mm 1200 mm N/A 1200 mm
M1500 mm 1500 mm N/A 1500 mm
N300 mm 300 mm N/A 300 mm
ON/A N/A N/A 50 mm
PN/A N/A See Table 2
and Fig. 6b N/A
QN/A N/A See Table 2
and Fig. 4 150 mm
NOTE N/A = Not applicable
aIn addition, the terminal should not be nearer than 150 mm (fanned draucht) or 300 mm (natural draught) to an opening in the building fabric formed for the purpose of accommodating
a built-in element such as a window frame, (see Figure C2). Separation distances are linked to the rated heat inputs as shown.
bThis dimension may be reduced to 75 mm for appliances of up to 5 kW heat input.
Minimum dimensions offlue terminal positions

FERROLI F24
12
1. CH flow
2.Safety Valve
3.Domestic hotwateroutlet
4.Gassupply
5.Domestic hotwaterinlet
6.CH return
Ø3/4" Ø1/2" Ø1/2" Ø1/2" Ø1/2" Ø3/4"
200
Ø118
150 min
65
5 min
183 min
200 min
970 min
269
110
12345 6
3.01Drilling Template (Top Flue Application)
Selectsuitable mountingpositionforboiler,usingthetemplate markflueoutlet andboilermountingpoints.Drill
two 10mm holes70mm deepto acceptthewall plugs.Fitstandardwall plugsontheleft andrightsideandthespecial
wall pluginthemiddle (fig. 13a). Fixthewall bracket to thewall usingstandardlocknut(M8) onbothsides.Mount
theboileronthewall bracket andfixusingthespecial antitheft nut(M8) asdescribedinthefig. 13a.Usingacore
drill cuta118mm diameterhole fortheflue.
Fig. 13a
Fig. 13b

FERROLI F24
13
3.02 Restrictor
For boiler operation, the restrictor supplied with the unit must be mounted following the instructions below.
Determine the correct size of flue restrictor required. Before inserting the flue gas duct in the boiler, check that
the restrictor fitted is correct and that it is correctly positioned (see fig. 14).
Holes Ø : 45 47 50
Ø
Fig. 14
CHOICE OF RESTRICTOR:
RESTRICTOR FOR TWO PIPE SYSTEM
Total flow resistance
of flue system
Use
restrictor
size
minimum maximum mm
0 m 13 m 45
13 m 23 m 47
23 m 38 m 50
38 m 48 m No restrictor
• With concentric systems:
- Choose correct restrictor from table below.
• With 2pipe system:
- Calculate the total flow resistance of the air and
flue pipes in metres (cap. 3.04.2)
- utilise the table shown below to choose the more
suitable restrictor for the flow resistance calculated
RESTRICTOR FOR CONCENTRIC SYSTEM
Flue lenght up to: Use restrictor
size
Ccncentric
60 / 100 1 bend + 1 meter 50 mm
1 bend + 3 meters No restrictor
Ccncentric
80 / 125
1 bend + 3 meters 45 mm
1 bend + 4 meters 50 mm
1 bend + 5 meters No restrictor
N.B.:the diameter ofthe hole is
stampedonthe restrictor
No restrictor is requiredfor
backoutlet flue

FERROLI F24
14
3.03 Top Outlet Concentric Flue Connection
3.03.1 Vertical concentric connection
Fig. 16
Avertical connector can be supplied for vertical
dischargewith concentricpipes.
The simple mounting and use of double lipgaskets
at the joints makes thisan extremely easy and safe
option.
For flue length up to 1mlong the 50 mmØ restrictor is
required. Longer than thisno restrictor isrequired.
Fig. 15
Concentric
Vertical
Connector
3.03.2Horizontal concentric connection
A90°bend (fig. 16)issupplied for the horizontal connection of airand flue gas pipes. Thiscan be oriented
towards the chosen wall indegrees of 45°.
Telescopic
DS
L
125
70
50*
30
95
80
80 -3 mm/m
Ø60 Ø80
70 min.
* = between 10 e 60 mm
190 270
L=S+D+255

FERROLI F24
15
Fig. 17
Notes on concentric horizontal installation
To locate the centre of the hole for passing the
pipes throughthe wall, refer to fig. 13b. Bear in
mind that the two concentricpipes must slope
downwards away from the boiler at arate of
about 3mm/m to avoidrainwater entering the
boiler. The concentricpipes making up the air
-flue gas duct must be sealed with the gasket
where they jointhe boiler (fig. 17). Outside, the
pipes should protrude from the wall between 10
and 60 mm (fig. 17).
3.03.3 Maximum concentric flue length
First table below shows the maximum flue lengths available for boilers with concentricsystems.
For correct calculation remember to include the reduction for bends on second table. Please refer to
3.02for use of restrictor.
Maximum flue lenght permissible 100 mm concentric 125 mm concentric
Vertical Horizontal* Vertical Horizontal*
Ferroli F24 m4m3m5m5
Reduction for bend
100 mm concentric bend 90°1 m
100 mm concentric bend 45°0,5 m
125 mm concentric bend 90°0,5 m
125 mm concentric bend 45°0,25 m
*For horizontal Flueingthe reduction for appliance bendor turret are already included.
max. 3 m
concentric
100/60
max. 4 m
concentric
100/60
Fig. 18aFig. 18b
Between
10-60 mm

FERROLI F24
16
Fig. 19
Ø80Ø80
AIRFLUE
1
2
3.04 Top Outlet: Two Pipe Flue System
3.04.1 Two pipe connection
Two separate ducts Ø80 for airintake and flue gas dischargecan
be directly connected to the boiler. For converson to top outlet
(see 3.05) mount the separate outlet kit1
Insert blankingplate 2
in remainingairintake
Connect flue duct to central hole Ø80 and airduct to left or right airintake hole Ø80. Insert blanking
plate 2inremaining airintake.
Avaried number of accessories for two pipe systems are available from Ferroli (ref. to page17). Before
installing your system please check viacalculation table at 3.08.2you are not exceeding the maximum
permissible length for the appliance.
Notes on two pipe system installation:
When using the two pipe system the flue dischargepipe must have a25mm airgap when passing through
combustible materials.
Where the flue dischargepipe passes throughthe airing space of an airing cupboard itmust be protected by anon
combustible guard or expanded metal giving an annular airgap of at least 25mm.
Where the flue dischargepipe passes throughawall containing cavity insulation,anon combustible sleeve must
be fitted. Additionally agap of 25mm between the sleeve and the insulation should be provided by cutting back
the insulation or packing loose fill bead insulation with mineral fibre.
Where the flue pipe isrun throughan unheated roof space itshould be insulated with non combustible insulating
material to prevent condensation. The flue pipe should be supported at intervals of not more than 1.8m and
the support should be preferably below ajoint.
3.04.2Two pipe flue system
•Calculatingmaximum permissible flue length.
The calculation method isbased on astandard reference parameter (1metre of horizontal airflue 80 diameter 80) for
the maximum length permissible for all the pipes +fittingsflow resistance coefficient. Inother words,for all components
and pipes inthe different installation configurations (vertical or horizontal,airor flue,etc.)and for all the fittings,a
flow resistance (reduction) equivalent to xmetre of horizontal airinduction pipe isindicated. For every boiler
model amaximum pipe length isprovided,expressed innmetres of horizontal airpipe. Inthisway,to calculate
the length of aproposed 2pipe air-flue system,add the flow resistance (reduction) inequivalent metres-air. For
every component and fitting present inthe system,and to check that the total isless than the maximum length
the permissible for the boiler model.
MPORTANT: the pipes andfittings flow resistance (reduction)have been summarisedon the followingpages.
The flow resistance values written referonly to Ferroli pipes andfittings.
Calculation routine
1. Utilise the pipes and fittingsflows resistance tables on the following pages and calculate the total flow
resistance inmetres-air,by adding the flow resistances of the components inthe whole air-flue system,based
on theirposition (vertical or horizontal,airinlet or flue outlet).
Please note that the same fitting,identified by aone code (i.e. 1pipe diameter 80,code KWMA83A),can offer
different flow resistances ifpositioned as airinlet or flue outlet,ifplaced vertically or horizontally.
The flow resistance ofthe special two pipe flue-airadapters do not have to be includedin the calculation
as they are already includedin the maximum lengthcalculation.
2. For the restrictors,please refer to cap. 3.02to determinate the correct diaphragm.
3. Check that the total flow resistance calculated isless or equal to 48metre,the maximum permissible
for Ferroli F24.

FERROLI F24
17
Air Flue
Vertical Horizontal Vertical Horizontal
Description
Male-female
flue Ø80
Female-female
bend 45°Ø80
Female-female
bend 90°Ø80
Male-female
bend 90°Ø80
Pipe fitting
M/M/F Ø80
with inspecting
plug+trap for
condensate drainage
system
Description
Air terminal of
inlet protection Ø80
Outlet flue air inlet
for concentric system
Ø80
Pipe fitting for outlet flue Ø80
Outlet flue air inlet for
connection with split end
Ø80
1112
1,2 2,2
1,5 2,5
1,5 2,5
7
Reduction
2
4
3
Air Flue
Vertical Horizontal Vertical Horizontal
12
Condensate flue
outlet
A
c
c
e
s
s
o
r
i
e
s
Ø
8
0
A
c
c
e
s
s
o
r
i
e
s
Ø
8
0
Spigot and socket
reduction Ø80/100
0
Reduction
Airwall terminal
products
of combustion Ø80
5
Male-female
flue Ø100
Male-female bend
45°Ø100
Male-female
bend 90°Ø100
Air wall terminal
products of
combustion Ø100
Air terminal
of outlet
protection
Ø100
0,4 0,4 0,4 0,8
0,6 1
0,8 1,3
3
1,5
A
c
c
e
s
s
o
r
i
e
s
Ø
1
0
0
Spigot and
socket
reduction
Ø 80/100
1,5 3
3.04.3 (continued)
Tab. 1 - Pipes and
fittings reduction table

FERROLI F24
18
For further accessories please refer to:
"Flue system manual for room sealed
boiler"Example of calculation for wall
inlet/outlet with 2 pipe system
maximum total flue length: 48 metres
Attention: Resistance of flue restrictor (if req.)
is included (see table on page 13)
Remove the flue restrictor.
The flue and air pipes must have an inclination
downward equal to 3% from boiler to outside.
Fig. 20
Example of wall inlet/outlet
2 pipe application
Example of roof
inlet/outlet
Example of direct roof flue outlet
and wall air inlet
3.04.4 Example of other installation with two pipe systems
Fig. 21
Fig. 23Fig. 22
Ref. N°of
pieces Description Code Length or reduction
1
2
3
4
5
6
7
1
13
1
1
1
12
1
Air bend 80 mm R/D = 0,75 1,5 m
Horizontal air pipe 13,0 m
Air wall terminal 2,0 m
Air inlet closing flange —
Flue bend 80 mm R/D = 0,75 2,5 m
Horizontal flue 24,0 m
Air wall terminal outlet flue 5,0 m
Total 48,0 m

FERROLI F24
19
3.05 For installation (back flue connection):
For direct back flue connection it is necessary to use the optional kit 1KWMR81A, and it is required to
alter the fan direction inside the boiler.
Follow carefully next procedure:
b
b
a
A
Fig. 24bFig. 24cFig. 24d
Removefanbypullingoffelectri-
cal connections. Pull off air
pressureswitchtubesfromtheair
pressure switchremove2screws
b. Rotate the fan downward to
disengage it fromthe securing
pin a.
Take off the four screws which
fix the back plate on sealed
chamber, remove and rotate the
plate through 90° and fit it to
the top of the boiler to cover
the original flue outlet. Secure
it in place with the four screws
removed previously.
Remove fan mountingplate by undoingthe three fixingscrews d. Rotate the fan through 90° so that the fan nozzle
points sideways. Fit the fan extension “B” on the fan nozzle and secure it in place usingsome silicone and “E”
screw. Secure the fan to the plate in the new position usingscrews in position c.
Fig. 24e
c
d
c
d
d
-
c
Common
For rear outlet
For upper outlet
Fig. 24g
B
E
For rear
outlet
c
c
c
Fig. 24f
d
dd
For upper
outlet
Fig. 24a

FERROLI F24
20
Boiler Mounting Plate
149
178
131
Fig. 25
Fig. 24h
Fixwiththescrews (b). Refitwiring connections to fan and airpressure switchtubes ensuring correct
orientation. I.E. red tube to airpressure switchconnection withred dot (+) and clear tube to airpressure
switchconnection withno paint marking (-).
Fitthefan into theboiler rotating thefront to engagewiththepina. Secure withthescrews b.
Rear
b
b