Ferroli SIGMA User guide

SIGM
INSTALLATION AND
SERVICING INSTRUCTIONS
Wall Mounted Cast Iron,
Gas Fired Boiler for Central Heating
Fan Assisted, Room Sealed,
Electronic Flame Ignition and Control
cod. 3543556/0 - 10/2001
Sigma 20 -40 GC N°41-267-17
Sigma 40 -60 GC N°41-267-18

2
Sigma
INDEX PAGE
1. TECHNICAL CHARACTERISTICS .......................................................................................3
.INSTALLATION ...................................................................................................................
.COMMISSIONINGANDTESTING...................................................................................
.DJUSTMENT .................................................................................................................. 3
.GAS CONVERSION ..........................................................................................................
.MINTEN NCEND CLE NING..................................................................................
.REPLACEMENT OFPARTS...............................................................................................
.FAULT FINDING................................................................................................................3
.USERINSTRUCTINS......................................................................................................33
.O.S.H.H.
Materials used in themanufacture of this applianceare non hazardousand no special precautionsare
required when servicing.
IMPORTANT
Your "benchmark" Installation, Commissioningand Service Record LogBook will be enclosed in your
customer information pack. This record must be completed and left with the end user.
Ferroli is amember of theBenchmarkinitiativeand fullysupports theaimsof theprogramme. Benchmark
has been introduced to improvethestandardsof installation and commissioning of central heating
systemsin theUK and to encouragetheregular servicing of all central heating systemsto ensure
safetyand efficiency.
CEMARK
CE markdocuments that theFerroli gas appliances complywith therequirementcontained in European
directives applicable to them.
In particular,theappliances complywith thefollowing CEE directives and thetechnical specifications
provided from them:
•Gas appliances directive90/396
•Efficiencies directive92/42
•Low tension directive73/23(modified from the93/68)
•Electromagnetic compatibilitydirective89/396 (modified from the93/68)

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Sigma
Fig. 1
Key
1 - Ø 22 mm flow outlet
2- Ø 22 mm return inlet
3- Ø 15 gas inlet
4- Rearair inlet/flue outlet
5- Topair inlet/Flue outlet
25
A
25
B 85
147
15
50
120 50
D
C
132
50
200
2
1
Front view
Right side view
220
Top view
3
4
600
620
200
78
5
Model
Sigma 20-40
Sigma 40-60
A
mm
320
400
B
mm
53
133
C
mm
35
30
D
mm
60
55
1. TECHNICAL CHARACTERISTICS
1.01 Introduction
The Sigma isdefinedas a“room sealed” boiler,all air requiredforcombustionistakenfrom outside the room in whichit
isinstalled. It isanew highperformance gas firedheat generator,whichisdesignedto provide indirect hot waterand/or
central heating.The cast ironheat exchangerissuitable foruse onfullypumpedhot water/central heatingsystems,
whichmaybe sealedoropenvented. Aspecial feature ofthisboilerisitsbuilt-in electronicflame ignitionandcontrol
unit makingburneroperationcompletelyautomaticandsafe.
The main componentsare as follows:
Cast ironheat exchangerspecificallyshapedforhighefficiency.
Ceramicfibre insulatedcombustionchamber
One stainless steel bladedburnerspecificallydesignedforthisboiler.
Fanfordischarge ofcombustionproductsandintake ofcombustionair.
Differential air pressure switch.Forsafetyreasons,thisensuresthe burnerignitesonlywhenthe fanis
functioningcorrectly.
Hermeticallysealedcompartment made from corrosion-resistant steel enclosingthe above components.
Combinationgas safetyvalve,complete withpressure stabiliser.
Central heatingflow temperature adjustment thermostat.
Overheat safetythermostat.
Electroniccontrol unit forautomaticflame ignitionandcontrol.
Central heatingflow temperature sensor.
1.02Dimension

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Sigma
Protection
level
IP 40
IP 40
Boiler
water
contents
1,3
1,6
litres
Weight
30
35
kg
Model
15
15
Gas inlet
3
Ø
Return
2
Ø
22
22
22
22
Flow
1
Ø
3
3
bar
Max. working
pressure
C.H.circuit
Connections Gas valve
Ø 1/2”
Honeywell
VK 4105 A
VK 4105 A
Sigma 20/40
Sigma 40/60
Model
Sigma 20/40
Sigma 40/60
G31-LPG
mbar
37
37
20
20
G20-NG
mbar
Burner gas pressures
G31-LPG
Nominal
mbar
36
36
Minimum
mbar
9,0
16,0
Nominal
mbar
14,0
15,3
Minimum
mbar
3,1
6,4
Gas supply pressures
G20-NG
11,7
17,6
Max
kW Min kW
5,5
11,4
13,0
19,5
Max
kW Min kW
6,1
12,7
14,4
21,7
Max
kW Min kW
6,8
14,1
Model
Sigma 20/40
Sigma 40/60
Heat
output
Heat
input
(net)
Heat
input
(gross)
G31-LPG
Ø
1,8
2,30
3,0
3,60
G20-NG
Ø
1,37
2,06
Max
0,64
1,34
Min
1,02
1,53
Max
0,48
0,99
Min
G20 m3/h-NG G31 kg/h-LPG
Injectors
(mm) Gas flow rates
N.B. • Maximum working temperature 82°C, adjustable between 60°C and 82°C.
1.03 Technicaldata

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Sigma
1.04 General Layout and Main Components
Fig. 2
19
27
132
1 16 1
34
11
86
121
68
63
24
83
44
22 21 7
5
151
49
43
28
90
1091
Air in
C.H.
in
C.H.
out
Flue out
Gas in
1.05Boiler water flowdiagram
Fig. 3
Key
1 Fixing points
5Roomsealed compartment
7Inlet gas-cock
10 Central heating flowoutlet
11 Central heating return inlet
16Fan
19Combustion chamber
21Gas injector
22 Burner
24Sparkandsensorelectrode
27Cast iron heat exchanger
28Fluecollectorfromheat exchanger
34Central heating flow
temperature sensor
43Airpressure switch
44 Gas valve
49Safetyoverheat thermostat
63Central heating temperature setting
68Controlbox withP. C . B .
83Full sequence automaticcontrol
86Automaticcontrolreset switch
90Flueoutlet pressure test point
91Airpressure test point
121Boiler shut-down warning
132Fluegas deflector
151Drain tap
.1 .2
20
30
40
50
60
70
80
90
200
300
.3 .4 .5 .6 .7 .8 .9 2 31
100
10
Water flow rate (m3/h)
Pressure drop mm wg
2
1
1=Sigma 20-40
2=Sigma 40-60
Pressure loss diagram

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Sigma
2. INSTALLATION
2.01 Important notices
Assembly, installation, first start up and maintenance must be carried out by competent persons only, in accordance
with all current technical regulations and directives.
Gas Safety(Installation &Use)Regulations:1996
In the interest ofsafety, it is the lawthat all gas appliances are installed by a competent person in accordance with the
above Regulations, Building Regulations/Building Standards Scotland, Codes ofPractice, current I.E.E. Regulations and
the byelaws ofthe Local Water Undertaking. Failure to comply with the Regulations may lead to prosecution;it is your
responsibility to ensure that the law is complied with.
This appliance must be installedstrictly in accordance withthese instructions andregulations:
The Gas Safety Regulations (Installations &Use)1996.
The Local Building Regulations.
The Building Regulations.
The Buildings Standards (Scotland -Consolidated)Regulations.
British Standards Codes ofPractice:
B.S. 5440 Part 12000 Flues
B.S. 5440 Part 21989 Air supply
B.S. 5449 1990 FORCEDCIRCULATION HOT WATER SYSTEMS
B.S. 6798 1987 INSTALLATION OFGASFIREDHOT WATER BOILERS
B.S. 6891 1989 GASINSTALLATIONS
B.S. 7671 1992 IEE WIRING REGULATIONS
B.S. 4814 1990 SPECIFICATION FOREXPANSION VESSELS
B.S. 5482 1994 INSTALLATION OFLPG
B.S. 7593 1992 TREATMENT OF WATER IN DOMESTIC HOT WATER CENTRAL HEATING SYSTEMS
Model Water Bye Laws
For Northern Ireland the rules in force apply
N.B.For Northern Ireland the rules in force apply.
Important -If the boiler is to be fitted in a timber framed building it should be fitted in accordance with
the institute ofgas engineers publication IGE/UP/1. If in doubt advice should be sought from the Local Gas
Region ofBritish Gas Plc.
2.01.01 Location ofBoiler
The installation ofthe Sigma must be on a suitable non-combustible load bearing wall which will provide an adequate fixing
for the boiler mounting bracket assembly. The location should be in an area where the water pipes will not be subjected
to frost conditions. In siting the boiler the following limitations must be observed:
The boiler may be installed in any room or internal space, although particular attention is drawn to the requirements ofthe
current I.E.E. wiring regulations and in Scotland the electrical provisions ofthe building regulations applicable in Scotland,
with respect to the installation ofthe boiler in a room or internal space containing a bath or shower.
Where a room sealed appliance is installed in a room containing a bath or shower any electrical switch or
appliance control utilising mains electricity must be situated so that it cannot be touched by a person using
the bath or shower.
2.01.02 Air Supply
The room or compartment in which the boiler is installed does not require a purpose provided vent when using
the standard concentric flue.
2.01.03Flue System
The boiler allows the flue outlet to be taken from the rear ofthe boiler, from either side or vertically.
It is absolutely essential, to ensure that products ofcombustion discharging from the terminal cannot re-enter
the building, or enter any adjacent building, through ventilations, windows, doors, natural air infiltration or
forced ventilation/air conditioning.

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Sigma
Fig. 4a
Gas
Pump
Expansion
vessel
Cold water
1
3
2
Filling point
Note: A bypass must be fitted as far
as possible from the boiler if
thermostatic radiator valves
are fitted thoughout.
2.01.04 GasSupply
If necessary the local Gas supplier should be consulted,at the installationplanning stage,inorder to establish
the availability of anadequate supply of gas.
Anexisting service pipe must not be used without prior consultationwith the Local Gas supplier.
A gas meter canonly be connected by the Local Gas supplier,or by a Local Gas suppliers Contractor.
Installationpipes should be fitted inaccordance with BS6891-1988.
Appliance inlet working pressure must be 20mbar MINIMUM (Natural gas -G20) or 37mbar MINIMUM (LPG-G31).
Pipeworkfrom the meter to the combinationboiler must be of anadequate size.
Do not use pipes of a smaller size thanthe combinationboiler inlet gascockconnection.
The complete installationmust be tested for gas soundness and purged as described inBS6981-1988. All pipework
must be adequately supported.
2.02 WaterSystem(sealedsystems)
Centralheating
Detailed recommendations are giveninBS6798,BS5449,BS6700 and CP342Part 2. Pipeworknot forming part of the
useful heating suface 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 permit
the whole system to be drained down. The draintaps should be inaccordance with BS2879. Copper tubing to BS2871,
Part 1is recommended for water carrying pipework. Pipeworkinhorizontal runs should have a gradient where possible
to facilitate the removal of air. Ensure that the boiler heat exchanger is not a natural point for air collection. A
typical sealed heating system illustrated infig. 4.
Typicalsealedfully pumpedheatingsystem

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Sigma
To DHW taps
Static Head
min. 1 m
max. 150 mm
Isolating valve
Drain
Flow
Return
Open
Vent
Open
Vent
Motorised valve
28 mm
gravity DHW
Isolating valve
CH Pump
By-pass
Motorised valve
22 mm CH Radiator Radiator
28 mm
28 mm
15 mm
22 mm
Schematic layout for gravity DHW and pumped CH for Sigma Boiler
Fig.4b

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Sigma
Important - If thermostatic radiator valves are fitted throughout a bypass must be fitted to ensure a minimum flow rate
through the boiler of 6 l/min. The bypass should be fitted as far as possible from the boiler.
2.02.01 Safety valve
Asafety valve complying with the requirements of BS 6750 Part 1must be fitted close to the boiler on the flow pipe by
means of a horizontal or vertically upward connection with no intervening valve or restrictions and should be positioned
to facilitate testing. The valve should be pre-set and nonadjustable to operate at a pressure of 3bar (45 Ibf/in2). It must be
arranged to discharge any water or steam through a pipe to a safe outlet position.
2.02.02 Pressure gauge
Apressure gauge of minimum range 0-4bar (0-60Ibf/in2) with a fill pressure indicator must be fitted to the system,
preferably at the same point as the expansion vessel in an easily visible position.
2.02.03Venting
Amethod of venting the system during filling and commissioning must be provided by fitting automatic air
vents or by venting manually.
2.02.04Expansion vessel
In a sealed system an expansion vessel complying with the requirements of BS 4814 must be fitted to the system
by means of a connection close to the inlet side of the circulating pump in accordance with the manufacturers
instructions,the connecting pipe being unrestricted and not less than 15 mm (1/2in)nominal size. The volume
of the vessel should be suitable for the system water content and the nitrogen or air charge pressure should
not be less than the system static head.
Further details of sealed system design can be obtained from BS 5449:Part 1and the British Gas publication entitled
Specifications for Domestic Wet Central Heating Systems.
2.02.05Watertreatment
If water treatment is used ferroli limited recommend only the
use of Fernoxor Sentinel water treatment products,which must
be used in accordance with the manufacturers instructions. For
further information contact:
FernoxManufacturing Co. LTD. Sentinel Division
Tandern house,Marlowe Way BetzDearborn LTD
Croydon,surrey,CRO 4YSWidnes,Cheshire WA88ND
Tel:[phone] Tel :[phone]
Note - If the boiler is installed in an existing system any
unsuitable additives must be removed by thorough 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.
2.03Gasconnection
Gas connection must be carried out using a rigid pipe.
The flow at the gas meter should be sufficient for the simultaneous use of all appliances connected to it. Connect
the gas supply to the boiler according to current regulations. The diameter of the gas cockleaving the boiler is not
the determining factor in choosing the diameter of the pipe between the appliance and the meter. This must be
selected in relation to length and pressure drop.
The whole of the gas installation including the meter should be inspected and tested for soundness and purged
in accordance with BS6891-1988.
VESSEL CHARGE
PRESSURE (bar)
INITIAL SYSTEM
PRESSURE (bar)
TOTAL WATER
CONTENT of SYSTEM
Litres
25
50
75
100
125
150
175
200
0.33
For syst. volumes other than
those given above, mult. the syst.
volume by the factor across.
0.5 1.0
EXPANSION VESSEL VOLUME (litres)
8.3
16.5
24.8
33.1
41.3
49.6
57.9
66.2
1.5
2.0
10.3
20.6
30.9
41.2
51.5
61.8
72.1
82.4
0.412
2.0
4.7
9.5
14.2
19.0
23.7
28.5
33.2
38.0
0.190
1.5
13.7
27.5
41.3
55.1
68.9
82.6
96.4
110.2
0.551
2.0
6.5
12.9
19.4
25.9
32.4
38.8
45.3
51.8
0.259
1.5
3.5
7.0
10.5
14.0
17.5
21.0
24.5
28.0
0.140
1.0
Sizingof expansion vessels:

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Sigma
105 min
205 min
254,5
620
Ø*
A
Boiler
mounting
plate
810 min
147
5 min
100
200 min
200
200 min 610
100
Fig. 5
Model
Sigma 20-40
Sigma 40-60
A
320
400
B
60 min.
140 min.
C
120
200
2.04 Wall Mounting
2.04.01DrillingTemp late
80
111
Ø118
WARNING:
C.H. connection
on this side
A
135
B
230 min.620
200 min.
C
80
91
Ø90
A
135B
WARNING:
C.H. connection
on this side
200 min.
620
C
Ø90
350 min.
165 min.
Minimum clearances and drilling template for standard
rear flue.
Fig. 6aFig. 6b
Drilling template for orizontal concentric flue. Drilling template for two pipe system withorizontal
air inlet.