Ferroli Sigma 30 FF 41-267-07 User guide

SIGMA
INSTALLATION AND
SERVICING INSTRUCTIONS
WALL MOUNTED CAST IRON,
GAS FIRED BOILER FOR CENTRAL HEATING
FAN ASSISTED, ROOM SEALED,
ELECTRONIC FLAME IGNITION AND CONTROL
cod. -----------/- - 10/99 Appr. Nr. B 98.06 A - 0461 AT 0344
G.C. NO:
Sigma 30 FF 41 - 267 - 07
Sigma 40 FF 41 - 267 - 08
Sigma 50 FF 41 - 267 - 09
Sigma 60 FF 41 - 267 - 10

INDEX PAGE
1. TECHNICAL CARACTERISTICS ........................................................................................ 3
2. INSTALLATION .................................................................................................................. 6
3. COMMISSIONING AND TESTING ................................................................................. 19
4. ADJUSTMENT ................................................................................................................. 20
5. GAS CONVERSION ......................................................................................................... 21
6. MAINTENANCE AND CLEANING ................................................................................. 22
7. REPLACEMENT OF PARTS ............................................................................................. 24
8. FAULT FINDING .............................................................................................................. 27
9. USER INSTRUCTIONS ..................................................................................................... 30
C.O.S.H.H.
Materials used in the manufacture of this appliance are non hazardous and no special precautions are required
when servicing.
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.
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)
Year 2000 Compliance Declaration
We will guarantee that this products is altogether suitable for the data change in the Year 2000 (boiler has no
dependence from date change) and that no disruptions will occur which is caused by this product.

3
Sigma
Fig. 1
Key
1 - Ø 22 mm flow outlet
2 - Ø 22 mm return inlet
3 - Ø 15 gas inlet
4 - Rear air inlet/flue outlet
5 - Top air 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 30-40
Sigma 50-60
A
mm
320
400
B
mm
53
133
C
mm
35
30
D
mm
60
55
1. TECHNICAL CARACTERISTICS
1.01 Introduction
The Sigma is defined as a “room sealed” boiler, all air required for combustion is taken from outside the room in which
it is installed. It is a new high performance gas fired heat generator, which is designed to provide indirect hot water and/or
central heating. The cast iron heat exchanger is suitable for use on fully pumped hot water/central heating systems, which
may be seal or open vented. A special feature of this boiler is its built-in electronic flame ignition and control unit making
burner operation completely automatic and safe.
The main components are as follows:
Cast iron heat exchanger specifically shaped for high efficiency.
Ceramic fibre insulated combustion chamber
One stainless steel bladed burner specifically designed for this boiler.
Fan for discharge of combustion products and intake of combustion air.
Differential air pressure switch. For safety reasons, this ensures the burner ignites only when the fan is functioning correctly.
Hermetically sealed compartment made from corrosion-resistant steel enclosing the above components.
Combination gas safety valve, complete with pressure stabiliser.
Central heating flow temperature adjustment thermostat.
Overheat safety thermostat.
Electronic control unit for automatic flame ignition and control.
Central heating flow temperature sensor.
1.02 Dimension

4
Sigma
Protection
level
IP 40
IP 40
IP 40
IP 40
Boiler
water
contents
1,3
1,3
1,6
1,6
litres
Weight
30
30
35
35
kg
Model
15
15
15
15
Gas inlet
3
Ø
Return
2
Ø
22
22
22
22
22
22
22
22
Flow
1
Ø
3
3
3
3
bar
Max. working
pressure
C.H.circuit
Connections Gas valve
Ø 1/2”
Honeywell
VK 4105 A
VK 4105 A
VK 4105 A
VK 4105 A
Sigma 30
Sigma 40
Sigma 50
Sigma 60
Model
Sigma 30
Sigma 40
Sigma 50
Sigma 60
G31-LPG
mbar
37
37
37
37
20
20
20
20
G20-NG
mbar
Burner gas pressures
G31-LPG
Nominal
mbar
36
36
36
36
Minimum
mbar
14,0
19,0
23,6
25,0
Nominal
mbar
15,3
14,0
15,3
15,3
Minimum
mbar
6,2
7,3
9,3
10,7
Gas supply pressures
G20-NG
8,8
11,7
14,7
17,6
Max
kW Min kW
5,5
8,5
11,4
14,4
9,8
13,0
16,3
19,5
Max
kW Min kW
6,1
9,4
12,7
16,0
10,9
14,4
18,1
21,7
Max
kW Min kW
6,8
10,5
14,1
17,8
Model
Sigma 30
Sigma 40
Sigma 50
Sigma 60
Heat
output
Heat
input
(net)
Heat
input
(gross)
G31-LPG
Ø
1,6
1,8
2,10
2,30
2,6
3,0
3,30
3,60
G20-NG
Ø
1,03
1,37
1,72
2,06
Max
0,64
0,99
1,34
1,69
Min
0,77
1,02
1,28
1,53
Max
0,48
0,74
0,99
1,25
Min
G20 m
3
/h-NG G31 kg/h-LPG
Injectors
(mm)
Gas flow rates
N.B. • Maximum working temperature 100°C, adjustable between 60°C and 82°C.
1.03 Technical data

5
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
1.05 Boiler water flow diagram
Fig. 3
Key
1Fixing points
5Room sealed compartment
7Inlet gas-cock
10 Central heating flow outlet
11 Central heating return inlet
16 Fan
19 Combustion chamber
21 Gas injector
22 Burner
24 Spark and sensor electrode
27 Cast iron heat exchanger
28 Flue collector from heat exchanger
34 Central heating flow
temperature sensor
43 Air pressure switch
44 Gas valve
49 Safety overheat thermostat
63 Central heating temperature setting
68 Control box with P.C.B.
83 Full sequence automatic control
86 Automatic control reset switch
90 Flue outlet pressure test point
91 Air pressure test point
121 Boiler shut-down warning
132 Flue gas deflector
151 Drain 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 (m
3
/h)
Pressure drop mm wg
2
1
1= Sigma 30-40
2= Sigma 50-60
Pressure loss diagram

6
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 of safety, it is the law that all gas appliances are installed by a competent person in accordance with the
above Regulations, Building Regulations/Building Standards Scotland, Codes of Practice, current I.E.E. Regulations and the
byelaws of the 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 installed strictly in accordance with these instructions and regulations:
The Gas Safety Regulations (Installations & Use) 1996.
The Local Building Regulations.
The Building Regulations.
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 1990 FORCED CIRCULATION HOT WATER SYSTEMS
B.S. 6798 1987 INSTALLATION OF GAS FIRED HOT WATER BOILERS
B.S. 6891 1989 GAS INSTALLATIONS
B.S. 7671 1992 IEE WIRING REGULATIONS
B.S. 4814 1990 SPECIFICATION FOR EXPANSION VESSELS
B.S. 5482 1994 INSTALLATION OF LPG
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 of
gas engineers publication IGE/UP/1. If in doubt advice should be sought from the Local Gas Region of British Gas Plc.
2.01.01 Location of Boiler
The installation of the 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 of the
current I.E.E. wiring regulations and in Scotland the electrical provisions of the building regulations applicable in Scotland,
with respect to the installation of the 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.
2.01.03 Flue System
The boiler allows the flue outlet to be taken from the rear of the boiler, from either side or vertically.
A standard flue length of 0.75 metres is provided. Alternative lengths of two or three metres can be supplied (equivalent
to wall thicknesses of up to 565, 1815 and 2815mm for rear flues, deduct 91mm plus distance from side wall for side outlet
flues). It is absolutely essential, to ensure that products of combustion 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.

7
Sigma
Fig. 4
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
thermostaticradiatorvalvesare
fitted thoughout.
2.01.04 Gas Supply
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 without 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 BS6891-1988.
Appliance inlet working pressure must be 20mbar MINIMUM (Natural gas - G20) or 37 mbar MINIMUM (LPG - G31).
Pipework from the meter to the combination boiler must be of an adequate size.
Do not use pipes of a smaller size than the combination boiler inlet gascock connection.
The complete installation must be tested for gas soundness and purged as described in BS6981-1988. All pipework must
be adequately supported.
2.02 Water System (sealed systems)
Central heating
Detailed recommendations are given in BS6798, BS5449, BS6700 and CP342 Part 2. Pipework not forming part of the useful
heating suface should be insulated to prevent any heat losses or possible freezing (i.e. in roof spaces or ventilated
underfloor spaces). Drain taps should be positioned at the lowest point of the system in accessible locations to permit the
whole system to be drained down. The drain taps should be in accordance with BS2879. Copper tubing to BS2871, Part
1 is recommended for water carrying pipework. Pipework in horizontal 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 in fig. 4.
Typical sealed fully pumped heating system

8
Sigma
Key
1 - Filling point C.H.
2 - Temporary connection
3 - Cold water supply
Fig. 5
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 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. A typical temporary filling loop is
shown in fig. 5.
Fittings manufactured from duplex (alpha-beta) brass are not
acceptable for underground use and certain water undertak-
ings will not accept their use above ground.
2.02.02 Safety valve
A safety valve complying with the requirements of BS 6750
Part 1 must 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 3 bar (45 Ibf/in2). It must
be arranged to discharge any water or steam through a pipe to a safe outlet position.
2.02.03 Pressure gauge
A pressure gauge of minimum range 0-4 bar (0-60 Ibf/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.
2.02.04 Venting
A method of venting the system during filling and commissioning must be provided by fitting automatic air vents or by
venting manually.
2.02.05 Expansion 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 (1/2 in) 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 1 and the British
Gas publication entitled Specifications for
Domestic Wet Central Heating Systems.
VESSEL CHARGE
PRESSURE (bar)
INITIAL SYSTEM
PRESSURE (bar)
TOTAL WATER
CONTENT of SYSTEM
Litres
25
50
75
100
125
150
175
200
3.5
7.0
10.5
14.0
17.5
21.0
24.5
28.0
6.5
12.9
19.4
25.9
32.4
38.8
45.3
51.8
13.7
27.5
41.3
55.1
68.9
82.6
96.4
110.2
4.7
9.5
14.2
19.0
23.7
28.5
33.2
38.0
10.3
20.6
30.9
41.2
51.5
61.8
72.1
82.4
8.3
16.5
24.8
33.1
41.3
49.6
57.9
66.2
0.140 0.259 0.551 0.190 0.412 0.33
For syst. volumes other than
those given above, mult. the syst.
volume by the factor across.
0.5 1.0 1.5
1.0 1.5 2.0 1.5 2.0 2.0
EXPANSION VESSEL VOLUME (litres)
Sizing of expansion vessels:

9
Sigma
2.02.06 Boiler water characteristics
If the water is harder than 18 clarke degrees, the water used should be treated to avoid possible scale in the boiler caused
by hard water or corrosion by aggressive water. It should be remembered that as a result of its low thermal conductivity,
even scale of just a few millimetres thick can lead to considerable overheating of the boiler walls, resulting in serious
problems.
IT IS ABSOLUTELY VITAL THAT THE WATER USED IS TREATED IN THE FOLLOWING CASES:
a) Extensive systems (containing large quantities of water);
b) Frequent additions of water to top-up the system.
If the system requires partial or total emptying, you are recommended to refill it with treated water.
2.02.07 Filling (sealed systems)
When cold, system pressure should be about 1 bar. If while running venting off of air dissolved in the water causes the
pressure of the central heating system to drop below the minimum level described above, the user must utilise a filling loop
to bring it back to the original value. During operation, water pressure in the boiler when hot should be about 1.5 - 2 bars.
After filling, always close and disconnect the filling loop.
Note - If there is a possibility of air pockets forming in certain points of the central heating system flow and return pipes,
you are recommended to fit an air vent valve at these points.
Note - When the boiler is installed below the level of the central heating system, single check valve should be fitted in the
eating flow to prevent gravity circulation around the heating circuit.
N.B. - The filling loop will be fitted by the installer at the time of fitting the system. It is NOT a part of the boiler.
2.03 Gas connection
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 cock leaving 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.
2.04 Wall Mounting
2.04.01 Drilling Template (Rear Flue Application)
120 min
220 min
Boiler
mounting
plate
254,5
620
Ø*
810 min
147
20 min
100
200 min
200
200 min 610 min
100
A
Fig. 6
Model
Sigma 30-40
Sigma 50-60
A
320
400

10
Sigma
2.04.02 Wall mounting instructions for Rear Flue Application
1
Select suitable mounting position for
boiler. Refer to fig. 6 for dimensions and
minimum clearance. Using the template
or mounting plate mark flue outlet and
boiler mounting points.
Fig. 7
Drill four 10 mm holes 70 mm deep to
accept the wall plug. Using a core drill
cut hole for the flue.
Drill cut a 118 mm diameter hole if it is
possible insert the flue-pipe from out-
side of the room; drill cut a 127 mm
diameter hole if to insert the flue-pipe
from inside of the room.
2
Fig. 8
Insert the plastic plugs.
3
Fig. 9
5a 5b
Ø 118
Fig. 11a Fig. 11b
4a 4b
Ø 127
Fig. 10a Fig. 10b
Insert flue-pipe from inside of the room (core drill 127 mm hole)...
... or insert flue-pipe from outside of the room (core drill 118 mm hole).

11
Sigma
11
Mark the aluminium flue pipe at the point it is flush with the
mounting plate. Add 15 mm to this mark and cut the
aluminium inner flue pipe at this point.
10
Insert the aluminium flue pipe into white plastic outer flue,
making sure the aluminium pipe sits fully and centrally into
the flue terminal.
Fig. 16 Fig. 17
15 mm
Cut the outer flue flush with the flange on the hanging plate.Through plate into air tube, drill two holes and fix in place
using two self tapping screws n°6 x 6mm long.
89
Fig. 14 Fig. 15
67
Position the wall plate on the wall. Fix plate to wall with the
square gasket between the wall and the plate use the large
diameter washers for the bolts ad screws.
Gently pull back until wall seal is flush with the wall.
Fig. 12 Fig. 13

12
Sigma
Fig. 21a
2.05 Top outlet flue conversion
Take off the four screws which fix the top sealed chamber
cover, remove the cover and gasket.
Fig. 22a Fig. 22b
1
3
Fig. 21b
2
4
12 13 14
Install the inner metal flue "a" into the
adapter "b".
Lift boiler with flue pipe in place, en-
gage inner and outer flue, slide into
position.
Make sure the inner flue is fully engage
in the flue terminal, secure boiler with
two nuts and washers "a" and "b".
Fig. 18 Fig. 19 Fig. 20
Remove fan by pulling off electrical connections. Pull off air
pressure switch tubes from the air pressure switch en.
Remove the two screws "b" and rotate the fan upward to
disengage it from the securing pin "a".
Rotate the fan upward to disengage it from the securing pin
"a". Remove the securing screw that locates the fan nozzle
extension to the fan and remove the nozzle extension.
Rotate the cover and gasket through 90°and fit it to the rear
of the boiler to cover the original flue outlet. Secure them
both in place with the four screws removed previously.

13
Sigma
9
10
Insert the correct restrictor.
(See section 2.07).
Fix the restrictor with the two screws
"a" inside the pipe connection "b".
Fig. 27
Fig. 28
b
b
a
Refit wiring connections to fan and air
pressure switch tubes ensuring correct
orientation. I.E. red tube to air pressure
switch connection with red dot (+) and
clear tube to air pressure switch con-
nection with no paint marking (-).
Fit the fan into the boiler rotating the
front upwards to engage with the pin
"a".
Secure with the screws "b".
Fig. 29
11
Boiler is fitted as standard with Ø36 (Sigma 30-40) or Ø41 (Sigma 50-60) restrictor. Identify on 2.07 the correct restrictor
for your flue system. If it is necessary to change it. follow instructions at step 7-10, if not, go to step 11.
Remove the two screws "a" from pipe
connection "b".
Remove restrictor "c".
Remove fan mounting plate by undoing
the three fixing screws "c".
c
d
c
d
d
-
c
For top outlet
Common
For rear outlet
For rear
outlet
For top
outlet
Fig. 23
7 8
Fig. 25 Fig. 26
56
Fig. 24
Rotate the fan through 90°so that the fan nozzle points upward. Secure the fan
to the plate in the new position using screws in position "d".

14
Sigma
2Example of direct roof flue outlet
and wall air inlet with 2 pipe system
3Example of concentric flue Ø 100
with vertical outlet flue use.
Warning • Back exit with Air/Flue T separator
is not possible
Fig. 32
Fig. 33
Note • Bear in mind that the two concentric
pipes must slope downwards away from the
boiler at a rate of about 3 mm/m to avoid
rainwater entering the boiler. Outside, the
pipes should protrude from the wall between
10 and 60 mm.
Warning • Back exit with coaxial bend is
not possible
1 Example of concentric flue Ø 100
with appliance bend use
2.06.01 Examples of top flue connection
Fig. 31
2.06 Top outlet Flue Connection
Three different connection are available from top of the boiler, using accessories as reported on fig. 30a, b e c and on
examples a next page.
Fig. 30
Cod. KWMR52A
Vertical Connection KWMR52A,
KWMR81U concentric bend and two
pipe separator KWMA90U can be
supplied on request.
Cod. KWMR81U Cod. KWMA90U
Top outlet horizontal
concentric flue
Top outlet two
pipe system
Top outlet vertical
concentric flue
123
Fig. 30a Fig. 30b Fig. 30c

15
Sigma
2.07 Restrictor and max flue length
2.07.01 Concentric Flue system
First table below shows the maximum flue lengths available for boilers with concentric systems.
For correct calculation remember to include the reduction for bend and flue terminals listed on second table.
Reduction for bend
100 mm concentric bend 90°
100 mm concentric bend 45°
125 mm concentric bend 90°
125 mm concentric bend 45°
1 m
0,5 m
0,5 m
0,25 m
Maximum flue
lenght permissible
100 mm contentric
Vertical *Horizontal
125 mm concentric
Vertical *Horizontal
100 mm
contentric
back exit
Sigma 30-40-50-60 4 m 3 m 5 m 5 m 1 m
*For horizontal flueing the reduction for appliance bend are already included.
Sigma
30-40 Sigma 50-60
A
B
C
Restrictor pipe
configuration
L2m
L2m
1m 3mL
L1m
Ø39
Ø36
Ø39
Ø36
Ø36
Ø46
Ø41
Ø46
Ø41
Ø41L1m
Boiler is fitted as standard with Ø36 and Ø41 restrictor.
For instruction on changing restrictor refer to step 7-10 at pages 14.
L (max. 3 m.)
L (max. 1 m.)
Fig. 34 Fig. 35
For the determination of the restrictor, identify your flue pipe configuration (A, B
or C) and choose the correct restrictor diameter from the restrictor table below.
L (max. 4 m.)
Fig. 36
AHorizontal concentric BBack concentric CVertical concentric

16
Sigma
Use restrictor:
Total flow resistance
0 - 20 metres
20 - 30 metres
30 - 40 metres
40 - 50 metres
Ø36
Ø36
Ø39
Ø39
Sigma 30 Ø36
Ø39
Ø39
not possible
Sigma 40 Ø41
Ø41
Ø46
Ø46
Sigma 50 Ø41
Ø46
Ø46
not possible
Sigma 60
Tab. 3
2.07.02 Two pipe flue system
1. Utilise the pipes and fittings flows resistance tables on the following pages and calculate the total flow resistance in
metres-air, by adding the flow resistances of the components in the whole air-flue system, based on their position
(vertical or horizontal, air inlet or flue outlet).
Please note that the same fitting, identified by a one code (i.e. 1 pipe diameter 80, code KWMA83A), can offer
different flow resistances if positioned as air inlet or flue outlet, if placed vertically or horizontally.
The flow resistance of the special two pipe flue-air adapters do not have to be included in the calculation as they
are already included in the maximum length calculation.
IMPORTANT: the pipes and fittings flow resistance (reduction) have been summarised on the following page. The
flow resistance values written refer only to Ferroli pipes and fittings.
2. Verify that the total flow resistance calculated is less or equal to 50 meter for Sigma 30 and 50 and 40 meter for
Sigma 40 and 60.
3. Choose the more suitable restrictor from table below.
DescriptionRef.
Connection for concentric pipe cod. KWMR52A1
N°of
pieces Length reduction
Total
Air/Flue T separator cod. KWMA90U2
Male - Female flue Ø 80 mm
3
4
Flue bend 80 mm5
Air wall terminal outlet flue Ø806
Air wall terminal air Ø807
Air
Flue
Horizontal
Vertical
Horizontal
Vertical
//
already included
1
/
2
5
2,5
5
2
17,5
1
1
1
/
1
5
1
1
1
Total flow resistance 17,5 m:
use restrictor Ø41
Tab. 5
1 m
Sigma 60
4
3
6
4
5
7
2
1
5 m
Example of calculation for wall inlet/outlet with 2 pipe system maximum total flue length: 40 metres
Fig. 37

17
Sigma
Fig. 39
2.08 Electrical connection
The boiler must be connected to a single phase 230V 50Hz electricity supply with a 3 A max. fuse and a bipolar switch with
contact opening of at least 3 mm fitted between the boiler and the electricity supply. The boiler must always be connected
to an efficient earth installation. In the electrical box, there is a 3 pole terminal block for connecting the boiler to the mains
(230V 50Hz) and a 3 pole block for connecting a circulating pump (not supplied). See Wiring diagram (fig. 41a) for the
connection of external control.
When the boiler is connected to an electricity main, it is essential TO ENSURE CORRECT POLARITY (LIVE: brown cable,
NEUTRAL: blue cable, EARTH: yellow-green cable).
All wiring must conform to current I.E.E. regulations.
Note: If the power supply cable has to be replaced, use “0.75mm (24/0.20) cable only to BS6500 with a maximum external
diameter of 8 mm.
101 X4 X5
121 86
63
141 5
X8
GCP
JP
X3
Key
63. CH temperature setting
86. Reset switch
101. Main P.C.B.
121. Boiler shut-down warning (Led)
X3-X4-X5-X8. Connectors
JP. Link
Temp.
sensor
NTC 34
kOhm
1000 kOhm
185 kOhm
80 kOhm
Temp.
25°C
60°C
80°C
2.07.03 Terminal Position
Pos. Minimum spacing ............................................................. mm
ADirectly below an openable window, air vent,
or any other ventilation opening ........................................... 300
BBelow gutters, soil pipes or drainpipes .................................. 75
CBelow Eaves........................................................................... 100
DBelow a Balcony..................................................................... 100
EFrom vertical drainpipes or soilpipes ...................................... 75
FFrom internal or external corners ......................................... 100
GAbove adjacent ground or balcony level .............................. 100
HFrom a surface facing the terminal ....................................... 600
IFacing another terminal ..................................................... 1,200
JFrom opening (door/window) in carport into dwelling ..... 1,200
KVertically from a terminal on the same wall .......................... 300
LHorizontally from a terminal on the same wall ..................... 300
NBelow carport ........................................................................ 600
Fig. 38
LF
F
K
F
G
J
G
F
HJ
DN
A
G
A
E
BC
G
A
K BC
F
C
A Quinnel Barrat and Quinnel guard (part. No. C2) should be screwed to the wall centrally over the terminal, when the
distance is less than 2 m from the outside floor.

18
Sigma
101 X4 X5
63
121 86
141 5
16
49
43
NO NC
C
123456789101112
83
24
32
72
SwL L N PL PN
230V ~
50 Hz
W
Blue
BR
BL
YGYG
Blue
BR V G
Blue
BL BL W RW O P
BR Blue
X8
GCP
JP
Fully
pumped
X3
34
2.08.01 Schematic wiring diagram for fully pumped system
Key
16 Fan
24 Spark and sensor elecktrode
32 Central heating pump (not fitted)
34 Central heating flow temperature
sensor
43 Air pressure switch
49 Safety thermostat
63 C.H. temperature adjustment
72 External controls
83 Full sequence automatic control on
gas valve
86 Reset switch
101 Main P.C.B.
121 Boiler shut-down warning (Led)
Fig. 40
If there are no external
controls fitted, connect the
SWL terminal to permanent
live in the junction box
Colors key
BR Brown
Blue Blue
BL Black
WWhite
OOrange
GGrey
RRed
VViolet
PPink
YG Yellow-Green

19
Sigma
3. COMMISSIONING AND TESTING
3.01 Checks to be carried out before starting up for the first time
When firing the boiler up for the first time, it is good practice to check:
that the isolation valves between the boiler and central heating systems are open;
that the central heating system is well filled and vented;
that there are no gas or water leaks from the central heating system or boiler;
that the electric connections are correct and the earth wire of the boiler is connected to an efficient earthing installation;
that there are no inflammable liquids or materials near the boiler;
that the central heating gas pressure and flow rate are as required.
3.02 Starting up the boiler
• Open the gas cock of the boiler.
• Vent air present in the pipe upstream of the gas valve.
• Turn on the switch (if present) or plug upstream of the boiler.
• Rotate the C.H. temperature adjustment knob above Min position.
• Set the room thermostat (if fitted) to maximum.
• At this point, the burner ignites and the boiler starts to function automatically, controlled by its control and safety devices.
Note - If after completing the start-up procedure correctly, the burner fails to ignite and the boiler shut down warning lights
up, wait about 15 seconds then press the reset switch. The reset electronic control unit will repeat the start-up cycle. If
after a second attempt the burners still fail to ignite, consult the paragraph “Troubleshooting”.
Note - If there is a power failure while the boiler is in operation, the burners automatically go out and re-ignite when the
power returns.
WARNING
If the system is filled with very cold water, will automatically light due to the frost thermostat sensing the low temperature.
The boiler will not shut down, until the water temperature reaches 10°C.
3.03 Shutting down
To shut down the boiler for short periods
•Set the temperature adjustment knob to "Off" position.
To shut down the boiler for long periods
• Turn off gas supply.
• Turn off the electricity supply.
IMPORTANT
The boiler is protected by integral frost protection, but if the boiler is not to be used for a long period of time, the system
should be drained.
Note: The frost thermostat operates even if the temperature adjustment knob is in the OFF position and it is necessary
therefore, if the system is drained, for the external electrical and gas supplies to be isolated.
It is recommended that a label be affixed to the appliance to draw attention to the fact that the system has been
drained.
3.04 Checks and tests after first start-up
Check there are no leaks in the gas and water circuits.
Check correct boiler start up by carrying out start up and shut down tests using the boiler stat.
Check the integrity of the air-flue pipes during boiler operation.
Check that the gas consumption indicated on the meter corresponds to that given in Technical Data (paragraph 1.03).
Check that water is circulating correct. Balance the radiators to ensure that the flow and return differential does not exceed
20°C.

20
Sigma
Fig. 42a
Diagram of pressures and outputs
with LPG (G31)
Note: with LPG (G31) the pressure regulating screw must be all the way in. Fig. 41
OUT
IN
 Inlet
pressure
Test Point
 Outlet
pressure
Test Point
Pressure regulator
protection plug
Inlet
gascock
4. ADJUSTMENT
4.01 Adjusting the gas pressure and heat output
The following adjustments must be carried out by qualified
personnel only.
To adjust boiler heat input simply adjust the burner pressure
gas via the pressure regulator on the gas valve (fig. 41).
Adjust the gas pressure at the burner by turning the pressure
regulating screw: turn it clockwise to increase the burner
pressure and anticlockwise to decrease it.
The diagrams indicate the variation in heat output to the
water as burner working pressure is varied (fig. 42a and 42b).
Adjusting boiler output to the actual requirements of the
central heating system will minimise boiler cycling thus
saving fuel, varying the output has virtually no effect on the
efficiency and combustion characteristics of the boiler.
Diagram of pressures and outputs
with Natural gas (G20)
5
6
7
8
9
10
11
12
13
78 9 10 11 12 13 14 15 16 17 18 19 20
kW
mbar
14
15
16
17
654
4
4
3
2
1
1= Sigma 30
2= Sigma 40
3= Sigma 50
4= Sigma 60
kW
mbar
18 19 20
15
20
25
30
35
9 101112131415161787654
43
21
Fig. 42b