Alpha CB50 Instruction
Installation and Servicing
Instructions
Alpha CB50
Wall Mounted, Fan Assisted, Room Sealed, Gas Fired
Combination Boiler with Unvented Hot Water Storage
(From Boiler Serial No. 27B32500001)
For Technical help or for Service call ...
ALPHA HELPLINE
Tel: 0870 3001964
Nepicar House, London Road,
Wrotham Heath, Sevenoaks,
Kent TN15 7RS
British Gas G.C. No. 47 532 18
For use with Natural Gas only
Leave these instructions with the User
CONTENTS
1 Introduction ....................................... 2
2 Technical data...................................3
3 General boiler information..................6
4 Installation......................................... 12
5 Commissioning ................................. 17
6 Boiler operation ................................. 19
7 Routine servicing...............................20
8 Component replacement ................... 22
9 Wiring diagrams ................................ 29
10 Fault finding ...................................... 31
11 Short parts list ................................... 35
12 Service history .................................. 36
1 INTRODUCTION
The Alpha CB50 boiler is a wall mounted, fan assisted room-sealed combination boiler, incorporating a 57 litre unvented hot
water storage cylinder. Heat output is controlled by a modulating gas valve, with fully automatic direct burner ignition.
The boiler, providing both central heating and domestic hot water at mains pressure, is designed for use with a fully pumped,
sealed and pressurised heating system using only Natural Gas.
The boiler is supplied with a pump, diverter valve, pressure relief valve, expansion vessel and pressure gauge fully assembled
and tested.
As supplied, the boiler will automatically modulate to provide central heating outputs between 10.5 and 28.0 kW (35 800 and
95 550 Btu/h).
The maximum output available for domestic hot water is 28.0 kW (95 550 Btu/h) and provides hot water at temperatures of up
to 65°C and flow rates of up to 20 litres/min (4.4 gal/min).
IMPORTANT
This boiler has been approved to the Building Regulations for unvented hot water storage systems and the Local Authority
must be notified of the intention to install. Therefore the installation must be carried out by a person competent to install
unvented hot water systems.
It is the law that all gas appliances are installed by a competent person, ie CORGI registered personnel, in accordance with
the following recommendations:-
Gas Safety (Installation and Use) Regulations 1984 (as amended)
All current Building Regulations issued by the Department of the Environment, i.e. Approved Document L1
Building Standards (Scotland) (Consolidation) Regulations issued by the Scottish Development Department
Local Water Bye Laws
Health & Safety Document No. 635 (The Electricity At Work Regulations 1989)
The installation should also be in accordance with the following British Standard Codes of Practice:BS 5440:1:2000 Flues
BS 5449:1990 Forced circulation hot water systems
BS 5546:2000 Installation of hot water supplies for domestic purposes
BS 6700:1997 Design, installation, testing and maintenance of services supplying water
BS 6798:2000 Installation of gas fired hot water boilers
BS 6891:1998 Gas installation
BS 7593:1992 Code of Practice for treatment of water in heating systems
BS 7671:2001 Requirements for electrical installations, IEE Wiring Regulations
If installation is in a timber framed building, refer to the Institute of Gas Engineers document IGE/UP/7.
This appliance meets the requirements of IPX4D, ie degree of protection against moisture.
Failure to install this appliance correctly could lead to prosecution. It is in your own interest and that of safety to ensure that the
law is complied with.
Manufacturer's instructions must NOT be taken in anyway as over-riding statutory obligations.
Note: Ensure that the Benchmark Log Book has been completed after the boiler has been installed and commissioned.
Notes: 1. Prior to installation ensure the appliance is stored upright in dry conditions and is transported in an upright position.
2. Ensure the appliance has been supplied with the unvented package and flue system.
Alpha CB50 - Contents/Introduction
2
2 TECHNICAL DATA
2.1 PERFORMANCE - NATURAL GAS (Cat I
Central Heating
Heat Input kW
(Gross) Btu/h
Heat Output (modulating) kW
Btu/h
Burner Pressure mbar
Setting in wg
Room sealed chamber
panel fitted
Gas Rate m³/h
ft³/h
CH Water Temp. (Approx.) °C
°F
MAX.
33.6
114 700
28.0
95 550
10.0
4.0
3.25
114.8
82
180
46 200
35 800
2.2 SYSTEM
Central Heating (Sealed System)
Max. Working System Pressure
Min. System Pressure
Max. System temperature
Pressure Relief Valve Setting
Expansion Vessel Size (pre-charge press.)
Flow Connection
Return Connection
Relief Valve Connection
Recommended System Pressure (cold)
2.5 bar
0.5 bar
82°C
3 bar (44 PSI)
8 L at 0.8 bar
22 mm
22 mm
15 mm
1.0 bar
2H
MIN.
13.5
10.5
1.7
0.68
1.24
43.9
30
86
)
Domestic Hot Water
Heat Input kW
(Gross) Btu/h
114 700
Output to Water (modulating) kW
Btu/h
Burner Pressure mbar
Setting in wg
Room sealed chamber
panel fitted
95 550
Gas Rate m³/h
ft³/h
Flow Rate L/min
G.P.M.
Outlet Water Temp. (Approx.) °C
°F
Time to raise water store by 50°C
Reheat time for 70% of store (boiler ON)
(boiler OFF)
Domestic Hot Water
Max. Hot Water Working Pressure
Max. Mains Inlet Pressure (inlet of pressure reducing valve)
Min. Mains Water Pressure
Mains Inlet Connection
DHW Outlet Connection
DHW Water Storage
Expansion Vessel Size (pre-charge press.)
Pressure Reducing Valve Setting
Temperature and Pressure Relief Valve
Expansion Relief Valve Setting
MAX.
33.6
28.0
10.0
4.0
3.25
114.8
18.0
4.0
65
149
8.0 minutes
3.5 minutes
5.0 minutes
MIN.
13.5
46 200
10.5
35 800
1.7
0.68
1.24
43.9
1.0
0.22
5
41
5.5 bar
12 bar
0.1 bar
15 mm
15 mm
57 L
4L at 2.5 bar
2.5 bar
90°C/7 bar
6 bar
2.3 COMPONENTS
Burner (15 blade)
Main Heat exchanger
DHW Storage Cylinder
Main Burner Injectors
Flue - Outer Duct
Flue - Inner Duct
Stainless steel
Stainless Steel
1.3 mm (15 off)
Epoxy coated
2.5 GENERAL
Dimensions Height
Width
Depth
Gas Connection
Primary Water Content
Air Duct Diameter
Flue Duct Diameter
Copper
Aluminium
900 mm
600 mm
450 mm
22 mm
3.2 L
100 mm
60 mm
2.4 INSTALLATION
Minimum Clearances for Servicing
Flue Terminal Size
Flue Terminal Protruding
Hole Size Required For Flue Assy.
Lift Weight
Weight Full and Operational
2.6 ELECTRICAL
Supply
External Fuse
Power Consumption
Internal Fuse
Electrode Spark Gap
Top
Bottom
Sides
Front
220 mm
250 mm
10 mm
450 mm
100 mm Dia.
145 mm
110 mm Dia.
72 kg
132 kg
230/240 V ~ 50 Hz
3 A
190 W
F2 A
2.0 to 4.0 mm
Alpha CB50 - Technical Data
3
2.7 FLUE LENGTHS
Flue length = 0.75 m (not including the terminal, which is supplied with the boiler)
Note: Additional flues (of the same length) are available.
Length of Flue Required:-
Rear Flue = wall thickness +195 mm
Side Flue = wall thickness + distance between wall and side of boiler + X mm (L/H side X = 140, R/H side X = 380)
Vertical Flue = distance from top of boiler side panel to required roof position minus 1 m for vertical terminal assembly
Maximum flue length = 4 m horizontal or 4 m vertical.
Each additional 90° Bend is equivalent to 1 m of flue length.
Each 45° Bend is equivalent to 0.5 m of flue length.
The Vertical Flue terminal assembly is equivalent to 1 m of flue length.
2.8 AVAILABLE PUMP HEAD FOR CENTRAL HEATING
Output Available pump head
kW
28.00
23.44
17.58
14.65
11.72
10.40
Btu/h
95563
80 000
60 000
50 000
40 000
35 495
17°C 20°C
metres
1.0
2.2
3.6
4.2
4.8
5.0
feet
3.28
7.22
11.8
13.7
15.7
16.4
metres
2.1
3.4
4.2
4.6
5.1
5.3
feet
6.9
11.1
13.7
15.1
16.7
17.3
litre/min
21.7
18.3
14.82
12.35
9.88
8.77
Flow rate
17°C 20°C 17°C 20°C
4.8
4.0
litre/min
18.4
15.2
12.60
10.50
8.40
7.45
gal/min
3.27
2.73
2.18
1.94
This information is based on 17°C and 20°C system design temperature difference.
2.9 ELECTRICAL CONNECTIONS
Note: This Appliance Must Be Earthed
An optional integral Clock kit is available if required.
Blue
Red
Wire
Brown
Wire
Wire
12345
Red
Not
Wire
Used
Internal Clock Terminals
gal/min
4.1
3.4
2.78
2.32
1.86
1.65
Pressure loss across boiler
metres
metres
3.5
2.6
1.6
1.2
0.9
0.8
feet
11.5
8.5
5.2
3.9
2.9
2.6
2.7
1.8
1.2
1.0
0.7
0.6
feet
8.9
5.9
3.9
3.3
2.3
2.0
1. Ensure wires are connected
correctly
2. Only fit the Alpha recommended
clock. Other clocks could cause
damage.
Clock connections
Alpha CB50 - Technical Data
4
WARNING
Boiler terminal block
Fig. 1
2.10 BOILER SCHEMATIC
1. Gas Service Cock
2. Heating On/Off Valve
3. Gas Valve
4. Pressure Gauge
5. Pump and Air Separator
6. Primary Drain Valve
7. Primary Pressure Switch
8. By-Pass
9. Automatic Flow Regulator
10. 3-Port Diverter Valve
11. Primary Temperature Sensor
12. Overheat Thermostat
13. C.H. Pressure Relief Valve
14. Automatic Air Vent
15. Main Burner
16. Main Heat Exchanger
17. Fan
18. Air pressure Switch
Fig. 2
19. Room Sealed Chamber
20. CH Expansion Vessel
21. Storage Cylinder
22. DHW Temperature/Pressure Relief Valve
23. DHW Storage Temperature Sensor
24. Secondary Heat Exchanger
25. DHW Expansion Vessel
26. Check Valve
27. Pressure Reducing Valve with Filter
28. Tundish
29. Ignition Electrodes
30. Flame Sensing Electrode
31. Flue Adapter
32. Flue Sample Point
33. DHW Expansion Relief Valve
34. Mains Inlet Valve
35. DHW Drain Point
36. Mains Inlet Filter
Alpha CB50 - Technical Data
5
3 GENERAL BOILER INFORMATION
3.1 GAS SUPPLY
The boiler requires a gas rate of 3.25 m³/h (114.8 ft³/h).
The meter and supply pipes must be capable of delivering this quantity of gas in addition to the demand from any other
appliances in the house. The boiler requires at least a 22 mm gas supply pipe.
The complete installation, including the meter, must be tested for gas soundness and purged as described in BS 6891.
3.2 ELECTRICAL SUPPLY
The boiler requires a 230/240 V ~ 50 Hz mains supply, fused at 3 A
The boiler must be earthed.
There must only be one common isolator, providing complete electrical isolation, for the boiler and any external controls.
Using PVC insulated cable not less than 0.75 mm² (24 x 0.2 mm) to BS 6500 Table 16, the boiler should be connected to a
fused three pin plug and unswitched shuttered socket outlet (both complying with BS 1363), or a fused double pole switch with
a contact separation of at least 3 mm in both poles.
Wiring external to the boiler must be in accordance with the current IEE Wiring Regulations (BS 7671).
Note: If a room thermostat is fitted, it must be suitable for 230/240 V switching
3.3 AIR SUPPLY
The boiler does not require any air vents for cooling in the room in which it is installed or when installed in a cupboard or
compartment. The minimum clearances for servicing must always be maintained.
Note: A cupboard or compartment used to enclose the boiler must be designed and constructed specifically for the purpose,
i.e. comply with the Building Regulations.
3.4 FLUE SYSTEM - Fig. 3
The flue system must be installed in accordance with BS 5440:1.
The flue assembly supplied for the boiler is 0.75 m in length.
For horizontal flues ensure there is a slight downward slope towards the terminal.
Additional flue components are available as follows:-
0.75 m flue
90° bend
45° bend
Vertical flue terminal assembly. Refer to the separate installation instructions supplied with the assembly.
A Twin Pipe Flue system and an Easy Flue system are available for use with the boiler. Refer to the separate instructions for
details.
The following methods determine the correct length of flue required.
For rear exit flue L = B + 195 mm
For side exit flue L = B + C + X mm (L/H side X = 140, R/H side X = 380).
For vertical flue L = H minus 1000 mm for vertical terminal assembly
Where L = Required flue length
B = Finished wall thickness
C = Distance from the inside wall to the side of the boiler
H = Distance from top of boiler side panel to roof position
Notes: 1. If an extra 90° bend is used, this reduces the maximum flue length by 1 m. Each 45° bend used reduces the
maximum flue length by 500 mm.
2. Minimum side clearance required is 10 mm.
3. Under no circumstances must the flue length (including allowances for extra bends) exceed the maximum
recommended length.
4. Failure to use Alpha flue components with the boiler will invalidate the boilers CE approval, warranty and may be
unsafe.
Alpha CB50 - General Boiler Information
6
HORIZONTAL FLUE OPTIONS
L
max = 4 metres, For L/H side flue X = 140, for R/H side flue X = 380
L = B + C + E + X mmL = B + C + X mm
C
E
L = B + E + F + X mm + (90° bend = 1 metre)
B
C
E
B
F
C
B
B
VERTICAL FLUE OPTIONS
max = 4 metres
H
L = B + C + X mm + (2 x 45° bends = 1 metre)
Fig. 3
Alpha CB50 - General Boiler Information
7
3.5 FLUE TERMINAL LOCATION - Fig. 4
Fig. 4
Terminal position
A Directly below an opening, air brick, windows, etc.
B Below gutters, soil pipes or drain pipes
C Below eaves
D Below balconies or car port roof
E From a vertical drain pipe or soil pipe
F From an internal or external corner
G Above ground, roof or balcony level
H From a surface facing the terminal
I From a terminal facing the terminal
J From an opening in the car port (e.g. door, window) into dwelling
K Vertically from a terminal on the same wall
L Horizontally from a terminal on the same wall
M Horizontally from an opening, air brick, window etc.
Min. distance
300 mm
75 mm
25 mm
25 mm
25 mm
25 mm
300 mm
600 mm
1200 mm
1200 mm
1500 mm
300 mm
300 mm
The flue terminal must be exposed to the external air and the position must allow the free passage of air across it at all times.
In certain weather conditions the terminal may emit a plume of steam. Avoid positioning the terminal where this may cause a nuisance.
If the terminal is fitted within 850 mm of a plastic or painted gutter or 450 mm of painted eaves or 300 mm of a plastic car port
roof, an aluminium shield at least 1 m long should be fitted to the underside of the gutter or painted surface. If the terminal is
fitted less than 2 m above a surface to which people have access, the terminal must be protected by a terminal guard.
A suitable guard is available from:
Tower Flue Components Ltd., Vale Rise, Tonbridge, Kent TN9 1TB
3.6 BOILER LOCATION
The boiler is not suitable for external installation.
The boiler must be installed on a flat vertical wall which is capable of supporting the weight of the boiler, i.e. 132 kg. The boiler
can be fitted to or adjacent to a wall comprising of a combustible material without the need for a special thermal insulation
barrier.
If the boiler is to be fitted in a timber framed building, it should be fitted in accordance with the British Gas publication 'Guide for
Gas Installations in Timber Frame Housing', reference DM2.
The boiler may be installed in any room or internal space, although particular attention is drawn to the requirements of the
current IEE Wiring (BS7671) 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 roomsealed boiler is installed in a room containing a bath or shower, it must not be possible for a person using the bath or shower
to touch any electrical switch or boiler control utilising mains electricity.
The boiler may be installed in a cupboard or compartment, provided it is correctly designed for that purpose, i.e. complies with
the Building Regulations and the requirements of BS 6798.
Alpha CB50 - General Boiler Information
8
3.7 CENTRAL HEATING SYSTEM - Fig. 5
The boiler is designed for use in a sealed central heating system in accordance with the requirements of BS 5449 and BS 6798.
The system should be designed to operate with flow temperatures of up to 82°C. When designing the system, the pump head, expansion
vessel size, mean radiator temperature, etc. must all be taken into account. Refer to the pump performance table for guidelines.
System volume - The expansion vessel incorporated into the boiler is suitable for a sealed heating system with a maximum
water content of 80 litres (18 gal). For guidance on water contents contact Alpha Therm Ltd. for Technical Data Sheet 15.
Above 80 litres, consideration should be given to fitting an additional expansion vessel fitted in the position shown in Fig. 5. To
check correct operation of the expansion vessel(s) the system pressure should not be more than 2.5 bar when the system is at
maximum operating temperature (for further guidance refer to BS 7074:1).
The boiler is supplied with the following components built in:CH Pressure relief valve - complying with BS 6759 and set to operate at 3 bar. The discharge pipe must be routed clear of the
boiler in such a manner that it can be seen, but cannot cause injury to persons or property.
Pressure gauge - to indicate the system pressure to be maintained.
Expansion vessel - conforming to BS 4814 with a capacity of 8 litres and pre-charged to a pressure of 0.5 bar.
By-pass - The boiler incorporates a by-pass. However, where all radiators are fitted with thermostatic radiator valves, it is
recommended that a system by-pass, preferably automatic, is fitted.
Fig. 5
3.8 FILLING THE CENTRAL HEATING SYSTEM - Figs. 6, 7
The system design pressure (cold) should be set to 1.0 bar. This pressure is equivalent to the maximum static head (see Fig. 5)
of 10.2 metres of water.
Provision should be made to replace water lost from the system. This can be by manual or automatic means, as shown in Figs.
6 and 7. The position for connecting an automatic make-up vessel is indicated in Fig. 5. A double check valve assembly must
be used, as shown in Fig. 7.
Filling of the system must be carried out in a manner approved by the local Water Undertaking. Where allowed, the system
may be filled via a temporary connection as shown in Fig. 6. After filling, always disconnect the flexible hose of the filling loop.
All fittings used in the system must be able to withstand pressures up to 3 bar.
Drain taps (to BS 2879) must be used to allow the system to be completely drained.
The heating system should be thoroughly flushed before the boiler is connected and again after the first heating.
If it is necessary to add inhibitor to the central heating system, contact Alpha Therm Ltd. for guidance.
Refer to BS 5449 and BS 6798 for further information.
Fig. 6
Heating circuit
return
Overflow
Double check
valve assembly
Stop
Test cock
valve
Fig. 7
Alpha cb50 - General Boiler Information
Mains
water
supply
Feed cistern to be
located above highest
point in the system
9
3.9 DOMESTIC HOT WATER SYSTEM
The mains water supply must be first connected to the pressure reducing valve (supplied with the boiler) which will regulate the
water supply to 2.5 bar. However, all taps and mixing valves used with the hot water system must be suitable for operating at a
pressure of up to 5.5 bar.
To ensure economic use, the pipe runs between the boiler and taps should be in 15 mm copper pipe and be as short as
possible. Where possible the pipework should be insulated to reduce heat loss.
Showers - A shower may be used with the boiler if required.
If a loose or flexible head type shower is used it may require the fitting of a double check valve, to comply with Water Bye Law 17.
Bidets - No anti-syphonage arrangements are necessary, provided the outlets are shrouded and it is not possible to attach a temporary
hand held spray. A supply of direct mains fed hot and cold water is permitted provided the appliance is of the over-rim flushing type.
Before the mains water supply pipe is connected to the boiler, it should be thoroughly flushed out to avoid the danger of dirt or
foreign matter entering the boiler and the filter incorporated within the pressure reducing valve cleaned.
The stored water temperature is adjustable to a maximum of 65°C. In hard water areas this should avoid possible scale build-up,
although it is still advisable to reduce the DHW thermostat setting in such areas. However, if descaling is necessary contact Alpha
Therm Ltd. for guidance.
3.10 UNVENTED HOT WATER STORAGE SYSTEM
The installation is subject to Building Regulations approval and the Local Authority must be notified of the intention to install.
The CB50 boiler is supplied with all the components required for an unvented hot water system, i.e. temperature/pressure and
expansion relief valves, expansion vessel, check valve and tundish. All these components are factory fitted, except for the
tundish which must be installed as follows:-
Discharge pipe - The discharge pipes from the temperature/pressure and expansion relief valves must be routed to the
tundish supplied and in 15 mm pipe. The discharge pipework from both relief valves may be joined together in the same sized
pipe, providing at least 22 mm pipework is connected downstream of the tundish.
Stop valve
Cold water supply
2.5 bar pressure
reducing valve
(supplied)
Filter
Mains
water
supply
Temperature/pressure
4L DHW expansion vessel
6 bar expansion
Check
valve
relief valve
Tundish
22 mm discharge
relief valve
pipe
Hot
water
Storage cylinder
Diverter
valve
Heating
Primary
Pump
Boiler
flow
Primary return
Fig. 8
Tundish - The tundish must be positioned within 500 mm of the appliance, so that it is visible to the User and away from electrical
devices. The minimum size of the discharge pipe downstream of the tundish is given in the following table.
Table 1
Valve
outlet size
G½
10
Minimum size of discharge
pipe 'D1' to tundish
15 mm
Alpha CB50 - General Boiler Information
Sizing of copper discharge pipe 'D2' - refer also to Fig. 9
Minimum size of discharge
pipe 'D2' from tundish
22 mm
28 mm
35 mm
Maximum resistance allowed,
expressed as a length of straight
pipe (i.e. no elbows or bends)
up to 9 m
up to 18 m
up to 27 m
Resistance created
by each elbow
or bend
0.8 m
1.0 m
1.4 m
The discharge pipework from the tundish:-
1. Shall fall continuously through its length.
2. Shall be of a heat resistant material, e.g. metal.
3. Shall not be fitted with any valves or taps.
4. Shall discharge to a safe visible position, e.g. into a gulley.
5. Shall have a minimum of 300 mm straight pipework directly from the tundish.
Note: Where children may play or otherwise come into contact with discharges, a wire cage or similar guard must be
positioned to prevent contact whilst maintaining visibility.
Refer to Fig. 9 for suggested methods of terminating the discharge pipe safely.
Where a single pipe serves a number of discharges, such as in blocks of flats, the number served should be limited to not more
than 6 systems so that any installation can be traced reasonably easily. The single common discharge pipe should be at least
one pipe size larger than the largest individual discharge pipe to be connected.
If the system is installed where discharges from safety devices may not be apparent, i.e. in dwellings occupied by blind, infirm or disabled
people, consideration should be given to the installation of an electronically operated device to warn when discharge takes place.
LOW LEVEL TERMINATION
Temperature/pressure
relief valve
Metal discharge pipe (D1)
from relief valve to tundish
D1
To expansion
relief valve
500 mm max.
300 mm
minimum
Metal discharge pipe (D2) from
tundish with continuous fall
Tundish
300 mm
minimum
D2
Pipe close to wall to
allow water to fan out
safely
100 mm max.
70 mm min.
Ground level
Gulley if
available
HIGH LEVEL TERMINATION
At high level, discharge onto a roof is acceptable providing the roof is capable of withstanding high temperatures and there is a
distance of 3 m from any plastic guttering systems that would collect such discharge.
Note: The discharge will consist of scalding water and steam. Asphalt, roofing felt and non-metallic rainwater goods may be
damaged by such discharges.
TERMINATION INTO A HOPPER
300 mm
minimum
D1
D2
Tundish
Type 'A'
air gap
End of pipe to be
clearly visible
Worked example:-
The example below is for a G½ temperature relief valve with a discharge pipe (D2)
having four elbows and a length of 7 m from the tundish to the point of discharge.
From Table 1 (page 10):-
Maximum resistance allowed for a straight length of 22 mm copper discharge pipe
(D2) from a G½ temperature relief valve is 9 m.
Subtract the resistance for four 22 mm elbows of 0.8 m each = 3.2 m.
Therefore the maximum permitted length equates to 9 - 3.2 = 5.8 m
5.8 m is less than the actual length of 7 m therefore calculate the next largest size.
Maximum resistance allowed for a straight length of 28 mm pipe (D2) from a G½
temperature relief valve equates to 18 m.
Subtract the resistance for four 28 mm elbows at 1.0 m each = 4 m.
Therefore the maximum permitted length equates to 18 - 4 = 14 m
As the actual length is 7 m, a 28 mm (D2) copper pipe will be satisfactory.
Fig. 9
Alpha CB50 - General Boiler Information
11
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