Alpha Alpha 240 Boiler Range User guide

Installation and Servicing
Instructions
Alpha 240/280
Range of Wall Mounted, Fan Assisted, Room Sealed,
Gas Fired Combination Boilers
Alpha 240P G.C. No. 47 532 09
Alpha 240E G.C. No. 47 532 06
Alpha 280E G.C. No. 47 532 08
Alpha 280P G.C. No. 47 532 12
Service Listed
0051
For use with Natural Gas only
Leave these instructions with the User
Nepicar House, London Road,
Wrotham Heath, Sevenoaks,
Kent TN15 7RS
For Technical help or for Service call ...
ALPHA HELPLINE
Tel: [phone]

2Alpha 240/280 - Contents/Introduction
CONTENTS
1 Introduction ....................................... 2
2 Technical data................................... 3
3 Generalboilerinformation.................. 7
4 Installation......................................... 11
5 Commissioning ................................. 16
6 Boileroperation ................................. 18
7 Routine servicing............................... 19
8 Componentreplacement ................... 21
9 Wiringdiagrams ................................ 34
10 Faultfinding ...................................... 38
11 Short parts list ................................... 43
12 Service history .................................. 44
The Alpha Range of boilers are wall mounted, fan assisted room-sealed combination boilers. Heat output is controlled by a
modulating gas valve.
The boilers, providing both central heating and domestic hot water at mains pressure, are designed for use with a fully
pumped, sealed and pressurised heating system using only Natural Gas.
The boilers are supplied with a pump, diverter valve, pressure relief valve, expansion vessel and pressure gauge fully
assembled and tested.
As supplied, the Alpha 240E and 240P boilers will automatically modulate to provide central heating outputs between 9.3 and
23.3 kW (31 700 and 79 500 Btu/h). The Alpha 280E and 280P boilers will provide central heating outputs between 9.3 and
28.0 kW (31 700 and 95 500 Btu/h).
The maximum output available for domestic hot water is 23.3 kW (79 500 Btu/h), capable of providing 9.5 litres/min with a
temperature rise of 35°C for the Alpha 240E and 240P boilers, and 28.0 kW (95 500 Btu/h), capable of providing 11.4 litres/min
with a temperature rise of 35°C for the Alpha 280E and 280P boilers.
IMPORTANT
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
All relevant Building Regulations issued by the Department of the Environment
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 5440:1:1990 Flues
BS 5449:1990 Forced circulation hot water systems
BS 5546:1990 Installation of hot water supplies for domestic purposes
BS 6700:1987 Design, installation, testing and maintenance of services supplying water
BS 6798:1987 Installation of gas fired hot water boilers
BS 6891:1989 Gas installation
BS 7593:1992 Code of Practice for treatment of water in heating systems
BS 7671:1992 Requirements for electrical installations, IEE Wiring Regulations
If installation is in a timber framed building, refer to the British Gas publication 'Guide for Gas Installations in Timber Frame
Housing' reference DM2.
This appliance meets the requirements of IP44, 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.
1 INTRODUCTION

3
2.1 PERFORMANCE - NATURAL GAS
2 TECHNICAL DATA
Alpha 240/280 - Technical Data
Min. Clearances for Servicing Top
Bottom
Sides
Front
Flue Terminal Size
Flue Terminal Protruding
Hole Size Required For Flue Assy.
Lift Weight 240E/P
280E/P
2.4 INSTALLATION
220 mm
250 mm
5 mm
450 mm
100 mm Dia.
115 mm
107 mm Dia.
39 kg
40 kg
MAX.
28.63
97 700
23.3
79 500
9.6
3.84
10.6
4.24
2.74
96.76
MIN.
11.76
40 150
9.3
31 700
1.1
0.44
2.1
0.84
1.13
39.9
Room sealed chamber
panel fitted
Room sealed chamber
panel removed
Central Heating
Heat Input kW
(Gross) Btu/h
Heat Output (modulating) kW
Btu/h
Burner Pressure mbar
Settings in wg
mbar
in wg
Gas Rate m³/h
ft³/h
MAX.
34.5
117 700
28.0
95 500
11.8
4.7
12.5
5.0
3.25
114.8
MIN.
11.76
40 150
9.3
31 700
1.5
0.6
1.9
0.76
1.13
39.9
Room sealed chamber
panel fitted
Room sealed chamber
panel removed
Central Heating
Heat Input kW
(Gross) Btu/h
Heat Output (modulating) kW
Btu/h
Burner Pressure mbar
Settings in wg
mbar
in wg
Gas Rate m³/h
ft³/h
MAX.
28.63
97 700
23.3
79 500
9.6
3.84
10.6
4.24
2.74
96.76
9.5
2.1
MIN.
11.76
40 150
9.3
31 700
1.1
0.44
2.1
0.84
1.13
39.9
Domestic Hot Water
Heat Input kW
(Gross) Btu/h
Output to Water (modulating) kW
Btu/h
Burner Pressure mbar
Settings in wg
mbar
in wg
Gas Rate m³/h
ft³/h
Flow Rate at 35°C Rise L/min
G.P.M.
Room sealed chamber
panel fitted
Room sealed chamber
panel removed
MAX.
34.5
117 700
28.0
95 500
11.8
4.7
12.5
5.0
3.25
114.8
11.4
2.5
MIN.
11.76
40 150
9.3
31 700
1.5
0.6
1.9
0.76
1.13
39.9
Domestic Hot Water
Heat Input kW
(Gross) Btu/h
Output to Water (modulating) kW
Btu/h
Burner Pressure mbar
Settings in wg
mbar
in wg
Gas Rate m³/h
ft³/h
Flow Rate at 35°C Rise L/min
G.P.M.
Room sealed chamber
panel fitted
Room sealed chamber
panel removed
Burner (15 blade)
Main Heat exchanger
DHW Heat Exchanger
Main Burner Injectors 240E/P
280E/P
Pilot Injector 240P/280P
Flue - Outer Duct
Flue - Inner Duct
Stainless steel
Copper
Stainless Steel
1.18 mm
1.25 mm
0.27 mm
Epoxy coated
Aluminium
2.3 COMPONENTS
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)
CH Water Temp. (Approx. max.)
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
82°C (180°F)
Domestic Hot Water
Max. Mains Inlet Water Pressure
Min. Mains Water Pressure
Min. DHW Flow Rate
Mains Inlet Connection
DHW Outlet Connection
DHW Water Content 240E/P
280E/P
Outlet Water Temp. (Approx. max.)
8 bar
0.2 bar
2.5 l/min
15 mm
15 mm
0.20 L
0.23 L
62°C (144°F)
2.2 SYSTEM
Alpha 240E and 240P Alpha 280E and 280P
Alpha 240E and 240P Alpha 280E and 280P

4Alpha 240/280 - Technical Data
Fig. 1
900 mm
450 mm
360 mm
22 mm
1.7 L
1.9 L
100 mm
60 mm
Dimensions Height
Width
Depth
Gas Connection
Primary Water Content 240E/P
280E/P
Air Duct Diameter
Flue Duct Diameter
2.5 GENERAL 2.6 ELECTRICAL
Supply
External Fuse
Power Consumption
Internal Fuse
Electrode Spark Gap 240E/280E
240P/280P
Thermocouple (240P/280P only):-
min. closed circuit output
230/240 V ~ 50 Hz
3 A
170 W
F2 A
1.2 to 3.5 mm
5 mm
10 mV
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 +150 mm
Side Flue = wall thickness + distance between wall and side of boiler + 185 mm
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
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
gal/min
3.32
2.78
2.32
1.85
1.47
Btu/h
79 500
60 000
50 000
40 000
31 700
kW
23.3
17.58
14.65
11.63
9.3
metres
2.33
3.00
3.45
3.85
4.20
feet
7.7
9.8
11.3
12.6
13.8
Output Available pump head
metres
2.95
3.45
3.75
4.05
4.35
feet
9.7
11.3
12.3
13.3
14.3
metres
2.50
2.20
2.00
1.70
1.45
feet
8.2
7.2
6.6
5.6
4.8
metres
2.25
2.00
1.75
1.50
1.35
feet
7.4
6.6
5.7
4.9
4.4
Pressure loss across boiler
gal/min
4.00
3.27
2.72
2.18
1.73
litre/min
15.10
12.60
10.50
8.40
6.70
17°C 20°C litre/min
18.10
14.80
12.36
9.89
7.84
17°C 20°C 17°C 20°C
Flow rate
This information is based on 17°C and 20°C system design temperature difference.
Note: For outputs upto 28 kW refer to section 3.7.
Boiler terminal block
1. Ensure wires are connected
correctly
2. Only fit the Alpha recommended
clock. Other clocks could cause
damage.
WARNING
Blue
Wire
Brown
Wire
Black
Wire
12345Internal Clock Terminals
Black
Wire
Not
Used
Clock connections
2.9 ELECTRICAL CONNECTIONS
Note: This Appliance Must Be Earthed
An optional integral Clock kit is available if required.

5
2.10 BOILER SCHEMATIC - Alpha 240P and 280P
Alpha 240/280 - Technical Data
1 - Pressure gauge
2 - Gas service cock
3 - Mains inlet on/off valve and filter
4 - Diverter valve assy.
5 - DHW flow valve
6 - Primary flow valve
7 - Differential pressure sensor
8 - Automatic by-pass
9 - DHW heat exchanger
10 - DHW expansion device (if fitted)
11 - Drain point
12 - Pressure relief valve
13 - DHW flow valve microswitch
14 - Primary flow valve microswitch
15 - Pump and air separator
16 - Automatic air vent
17 - DHW temperature sensor
18 - Primary temperature sensor
19 - Overheat thermostat
20 - Expansion vessel
21 - Gas valve
22 - Main burner injector
23 - Main burner
24 - Pilot burner
25 - Thermocouple
26 - Main heat exchanger
27 - Flue hood
28 - Fan
29 - Air pressure switch
30 - Positive pressure point
31 - Negative pressure point
32 - Flue adaptor
33 - Flue sample point
34 - Room sealed chamber
35 - On/off valve
36 - On/off valve and filter
Domestic
Hot Water
Outlet
Gas Cold Mains
Water Inlet Heating Return
Heating
Flow
Fig. 2

6
2.11 BOILER SCHEMATIC - Alpha 240E and 280E
Alpha 240/280 - Technical Data
1 - Pressure gauge
2 - Gas service cock
3 - Mains inlet on/off valve and filter
4 - Diverter valve assy.
5 - DHW flow valve
6 - Primary flow valve
7 - Differential pressure sensor
8 - Automatic by-pass
9 - DHW heat exchanger
10 - DHW expansion device (if fitted)
11 - Drain point
12 - Pressure relief valve
13 - DHW flow valve microswitch
14 - Primary flow valve microswitch
15 - Pump and air separator
16 - Automatic air vent
17 - DHW temperature sensor
18 - Primary temperature sensor
19 - Overheat thermostat
20 - Expansion vessel
21 - Gas valve
22 - Main burner injector
23 - Main burner
24 - Ignition electrodes
25 - Flame sensing electrode
26 - Main heat exchanger
27 - Flue hood
28 - Fan
29 - Air pressure switch
30 - Positive pressure point
31 - Negative pressure point
32 - Flue adaptor
33 - Flue sample point
34 - Room sealed chamber
35 - On/off valve
36 - On/off valve and filter
Domestic
Hot Water
Outlet
Gas Cold Mains
Water Inlet Heating Return
Heating
Flow
Fig. 3

7
3.1 GAS SUPPLY
The Alpha 240E and 240P boilers require a gas rate of 2.74 m³/h (96.76 ft³/h) and the Alpha 280E and 280P 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. 4
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 all the boilers in the range. Refer to the separate
instructions for details.
Also, available for use with the Alpha 240E and 240P only is a Low Easy Flue system. Refer to the separate instructions for
details.
The following methods determine the correct length of flue required.
For rear exit flue L = B + 150 mm
For side exit flue L = B + C + 185 mm (min. side clearance required is 5 mm)
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
Note: 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. Under no circumstances must the flue length (including allowances for extra bends) exceed 4 metres.
3. Failure to use Alpha flue components with the boiler will invalidate the boilers CE approval, warranty and may be unsafe.
3 GENERAL BOILER INFORMATION
Alpha 240/280 - General Boiler Information

8
HORIZONTAL FLUE OPTIONS - Lmax = 4 metres
L = B + C + E + 185 mm
Alpha 240/280 - General Boiler Information
L = B + C + 185 mm
CB
E
CB
E
B
F
B
C
L = B + E + F + 185 mm + (90° bend = 1 metre)
L = B + C + 185 mm + (2 x 45° bends = 1 metre)
Not less than
300 mm
Not less than
450 mm
HH
Not less than
450 mm
Not less than
300 mm
Hmax = 3 metresHmax = 4 metres
Fig. 4
VERTICAL FLUE OPTIONS

9
3.5 FLUE TERMINAL LOCATION - Fig. 5
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
300 mm
75 mm
25 mm
25 mm
25 mm
25 mm
300 mm
600 mm
1200 mm
1200 mm
1500 mm
300 mm
Min. distance
Terminal position
Fig. 5
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 (type K3 - G.C. No. 393 554) 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.
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.
Theboilermaybeinstalledinanyroomorinternalspace,althoughparticularattentionisdrawntotherequirementsofthecurrentIEEWiring
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 boiler is installed in a room containing a bath or
shower,itmustnotbepossibleforapersonusingthebathorshowertotouchanyelectricalswitchorboilercontrolutilisingmainselectricity.
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 240/280 - General Boiler Information

10
3.7 CENTRAL HEATING SYSTEM - Fig. 6
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. 6. 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:-
Pressure relief valve - complying with BS 6759 and set to operate at 3 bar. The discharge pipe must be routed clear of the
boiler to a drain, 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 0.8 bar.
By-pass - Where all radiators are fitted with thermostatic radiator valves an external by-pass may be required.
Alpha 240/280 - General Boiler Information
Feed cistern to be
located above highest
point in the system
Mains
water
supply
Stop
valve
Test cock
Double check
valve assembly
Overflow
Heating circuit
return
Heating circuit
return Mains
water
supply
Double check
valve assembly
Stop
valve Test cock
Air inlet
valve
Filling loop
temporarily connected
Hose
unions
Fig. 7 Fig. 8
3.8 FILLING THE CENTRAL HEATING SYSTEM - Figs. 7, 8
Thesystemdesignpressure (cold) shouldbesetto1.0bar. Thispressureisequivalenttoa static head(seeFig.6)of10.2 metresofwater.
Provision should be made to replace water lost from the system. This can be by manual or automatic means, as shown in Figs.
7 and 8. The position for connecting an automatic make-up vessel is indicated in Fig. 6. A double check valve assembly must
be used, as shown in Fig. 8.
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. 7. 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 required to add inhibitor to the system, refer to Alpha Therm Ltd. for guidance.
Refer to BS 5449 and BS 6798 for further information.
Note: A drain tap should be installed at the lowest
point of the heating circuit and beneath the appliance.
System
drain tap
Note: If the mains is fitted with water
meter, check valves or loose jumper stop
cock, then a DHW expansion device must
be fitted.
Static head of system
Make up vessel
DHW outlet
Mains water inlet
Additional expansion
vessel (if required)
Automatic
air vent
Boiler
casing
Heating flow
Heatingreturn
Filling point
Double check valve assy.
By-pass could be a 15 mm pipe controlled
by a valve or an uncontrolled radiator.
Heating
by-pass
(If required)
Fig. 6