alpha 240E User guide

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Installation and Servicing

Instructions

Alpha 240/280

Range of Wall Mounted, Fan Assisted, Room Sealed,

Gas Fired Combination Boilers

For Technical help or for Service call ...

ALPHA HELPLINE

Tel: (01322) 669443

Goldsel Road,

Swanley, K ent BR8 8EX

F ax: (01322) 615017

*HEJEID/=I

Service Listed

Alpha 240P G.C. No. 47 532 09

0051

Leave these instructions with the User

Alpha 240E G.C. No. 47 532 06 Alpha 280E G.C. No. 47 532 08 Alpha 280P G.C. No. 47 532 12

For use with Natural Gas only

CONTENTS

1 Introduction ....................................... 2

2 Technical data...................................3

3 General boiler information..................7

4 Installation......................................... 11

5 Commissioning ................................. 16

6 Boiler operation ................................. 18

7 Routine servicing...............................19

8 Component replacement ................... 21

9 Wiring diagrams ................................ 34

10 Fault finding ...................................... 38

11 Short parts list ................................... 43

12 Service history .................................. 44

1 INTRODUCTION

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.

Alpha 240/280 - Contents/Introduction

2 TECHNICAL DATA

2.1 PERFORMANCE - NATURAL GAS

Alpha 240E and 240P Alpha 280E and 280P

Central Heating

Heat Input kW (Gross) Btu/h Heat Output (modulating) kW

Btu/h

Burner Pressure mbar Settings in wg

Room sealed chamber panel fitted

Room sealed chamber panel removed

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

Alpha 240E and 240P Alpha 280E and 280P

Domestic Hot Water

Heat Input kW (Gross) Btu/h Output to Water (modulating) kW

Btu/h

Burner Pressure mbar Settings in wg

Room sealed chamber panel fitted

Room sealed chamber panel removed

mbar in wg

Gas Rate m³/h

ft³/h

Flow Rate at 35°C Rise L/min

G.P.M.

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

MIN.

11.76

40 150

9.3

31 700

1.1

0.44

2.1

0.84

1.13

39.9

Central Heating

Heat Input kW (Gross) Btu/h Heat Output (modulating) kW

Burner Pressure mbar Settings in wg

Room sealed chamber panel fitted

Room sealed chamber panel removed

Gas Rate m³/h

Domestic Hot Water

Heat Input kW (Gross) Btu/h Output to Water (modulating) kW

Burner Pressure mbar Settings in wg

Room sealed chamber panel fitted

Room sealed chamber panel removed

Gas Rate m³/h

Flow Rate at 35°C Rise L/min

Btu/h

mbar in wg

ft³/h

Btu/h

mbar in wg

ft³/h

G.P.M.

MAX.

34.5

117 700

28.0

95 500

11.8

4.7

12.5

5.0

3.25

114.8

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

MIN.

11.76

40 150

9.3

31 700

1.5

0.6

1.9

0.76

1.13

39.9

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) CH Water Temp. (Approx. max.)

2.3 COMPONENTS

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

Stainless Steel

Epoxy coated

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)

Copper

1.18 mm

1.25 mm

0.27 mm

Aluminium

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.)

2.4 INSTALLATION

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

8 bar

0.2 bar

2.5 l/min 15 mm 15 mm

0.20 L

0.23 L

62°C (144°F)

220 mm 250 mm

5 mm

450 mm

100 mm Dia.

115 mm

107 mm Dia.

39 kg 40 kg

Alpha 240/280 - Technical Data

2.5 GENERAL 2.6 ELECTRICAL

Dimensions Height

Width

Depth Gas Connection Primary Water Content 240E/P

280E/P Air Duct Diameter Flue Duct Diameter

900 mm 450 mm 360 mm

22 mm

1.7 L

1.9 L

100 mm

60 mm

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

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

3 A

170 W

F2 A

1.2 to 3.5 mm 5 mm

10 mV

2.8 AVAILABLE PUMP HEAD FOR CENTRAL HEATING

Output Available pump head

23.3

17.58

14.65

11.63

9.3

Btu/h

79 500 60 000 50 000 40 000 31 700

17°C 20°C

metres

2.33

3.00

3.45

3.85

4.20

feet

7.7

9.8

11.3

12.6

13.8

metres

2.95

3.45

3.75

4.05

4.35

feet

9.7

11.3

12.3

13.3

14.3

litre/min

18.10

14.80

12.36

9.89

7.84

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.

Flow rate

17°C 20°C 17°C 20°C

gal/min

4.00

3.27

2.72

2.18

1.73

litre/min

15.10

12.60

10.50

8.40

6.70

2.9 ELECTRICAL CONNECTIONS

Note: This Appliance Must Be Earthed

An optional integral Clock kit is available if required.

Blue

Black

Wire

Brown

Wire

12345

Black

Not

Wire

Used

Internal Clock Terminals

WARNING

1. Ensure wires are connected correctly

2. Only fit the Alpha recommended clock. Other clocks could cause damage.

gal/min

3.32

2.78

2.32

1.85

1.47

Pressure loss across boiler

metres

2.50

2.20

2.00

1.70

1.45

feet

8.2

7.2

6.6

5.6

4.8

2.25

2.00

1.75

1.50

1.35

feet

7.4

6.6

5.7

4.9

4.4

Clock connections

Alpha 240/280 - Technical Data

Boiler terminal block

Fig. 1

2.10 BOILER SCHEMATIC - Alpha 240P and 280P

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

Heating

Flow

Domestic

Hot Water

Outlet

Gas Cold Mains

Water Inlet

Heating

Return

Fig. 2

Alpha 240/280 - Technical Data

2.11 BOILER SCHEMATIC - Alpha 240E and 280E

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

Heating

Flow

Alpha 240/280 - Technical Data

Domestic

Hot Water

Outlet

Gas Cold Mains

Water Inlet

Heating

Return

Fig. 3

3 GENERAL BOILER INFORMATION

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.

Alpha 240/280 - General Boiler Information

HORIZONTAL FLUE OPTIONS - Lmax = 4 metres

L = B + C + 185 mm

L = B + E + F + 185 mm + (90° bend = 1 metre)

L = B + C + E + 185 mm

VERTICAL FLUE OPTIONS

Not less than

300 mm

Not less than

450 mm

L = B + C + 185 mm + (2 x 45° bends = 1 metre)

Hmax = 3 metresHmax = 4 metres

Not less than

450 mm

Not less than

300 mm

Alpha 240/280 - General Boiler Information

Fig. 4

3.5 FLUE TERMINAL LOCATION - Fig. 5

Fig. 5

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

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

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

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. The boiler may be installed in any room or internal space, although particular attention is drawn to the requirements of the current IEE 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 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 240/280 - General Boiler Information

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.

Make up vessel

Static head of system

Boiler

casing

Automatic air vent

Additional expansion vessel (if required)

Double check valve assy.

Heating by-pass

(If required)

By-pass could be a 15 mm pipe controlled by a valve or an uncontrolled radiator.

Heating flow

Filling point

DHW outlet Mains water inlet

Note: If the mains is fitted with water meter, check valves or loose jumper stop cock, then a DHW expansion device must be fitted.

Note: A drain tap should be installed at the lowest point of the heating circuit and beneath the appliance.

Heating return

System drain tap

Fig. 6

3.8 FILLING THE CENTRAL HEATING SYSTEM - Figs. 7, 8

The system design pressure (cold) should be set to 1.0 bar. This pressure is equivalent to a static head (see Fig. 6) 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.

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.

Air inlet

valve

Double check

Heating circuit

return

valve assembly

Stop valve

Test cock

temporarily connected

Fig. 7 Fig. 8

Alpha 240/280 - General Boiler Information

Hose

unions

Filling loop

Mains water supply

Heating circuit

return

Double check

valve assembly

Test cock

Overflow

Stop valve

Mains water supply

Feed cistern to be located above highest point in the system

3.9 DOMESTIC HOT WATER SYSTEM

The minimum flow rate needed for the flow switch and burner to operate is 2.5 litres/min. The incoming mains water pressure should be between 0.2 and 8 bar to ensure efficient operation. If the pressure is above 7 bar

a pressure reducing valve must be fitted. 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. All taps and mixing valves used with the hot water system must be suitable for operating at a mains pressure of up to 8 bar. 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 overrim 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.

The mains water supply connection to the boiler must be the first connection from the mains supply. Note: The boiler has been provided with the facility for fitting an expansion device, i.e. shock arrestor or expansion vessel in

the DHW circuit (see Fig. 35). An optional kit is available from Alpha Therm Ltd., Goldsel Road, Swanley, Kent BR8 8EX. If the mains water supply has been fitted with check valves, water meter or a loose jumper stop cock, then an expansion device

must be fitted.

4 INSTALLATION

4.1 UNPACKING

1. The boxes required when the boiler is installed with a horizontal flue are as follows:Box 1 Cased boiler

Water and gas valves plus washers Water fittings and filling loop Mounting bracket plus screws and wall plugs Flue terminal and flue sealing collar plus 2 screws

Literature pack and Wall template Box 2 90° flue bend with clamp (not required for vertical flue) Box 3 0.75 m flue (for side and rear flue) with two clamps and inner duct support

2. Unpack boiler and remove loose items packs.

3. Remove the two screws at the top of the front casing. Slide it up and lift it off.

4.2 CLEARANCES REQUIRED - Fig. 9

360 mm

5 mm

900 mm

220 mm

450 mm

Minimum clearances

5 mm

Minimum clearance of 450 mm from front of boiler

250 mm

Fig. 9

Alpha 240/280 - General Boiler Information/Installation

4.3 PREPARE THE WALL - Figs. 10, 10A

1. Decide upon the position of the boiler taking into account the clearances required for servicing and the flue terminal position.

Rear exit hole 110 mm dia.

Ensure line is level

190 mm

2. Tape the template to the wall (ensure it is level and the right way up) and mark the position of the holes for the boiler mounting bracket and bottom fixings. If rear exit flue is used, mark the position of the hole for the flue. Note: If pipework is routed at the rear of the boiler (top pipe connections), mark the four fixing holes shown in Fig. 10A.

3. Side exit flue - Continue the horizontal centre line of the flue across the wall to the side wall, then along the side wall 190 mm (ensure the lines are horizontal). This will give the position of the centre of the hole for the flue.

4. Cut the 110 mm diameter hole (or use a 107 mm core drill) in

135 mm

Top fixing holes

Position of 110 mm hole to be cut for side exit flue

Wall mounting bracket

the wall for the flue. Note: For internal fitting of the flue, using the flue sealing collar supplied, cut a 127 mm dia. flue hole using a 127 mm core drill.

5. Drill the fixing holes (8 mm dia.) to accept the No.10 plugs supplied. Using the washers supplied with the screws, fit the mounting bracket. Note: When pipework is routed at the rear of the boiler, i.e. top pipe

Boiler outline

Template

Fig. 10

Bottom fixing holes

connections the mounting bracket is not used. (Refer to fig. 10A). Fit the top fixing screws, leaving just enough protruding, to hang the boiler on.

6. Top pipe connections - Remove the mounting cross bar from the rear of the boiler and fit it to the top as shown in Fig. 10A.

Mounting cross bar

Top fixing holes

Note: Preform the

Position for

15 mm and 22 mm

pipework

Bottom

fixing holes

35 60 3560

pipework at the back of the boiler before hanging the boiler

Fig. 10A

4.4 FIT THE BOILER - Refer to Fig. 10

1. Lift the boiler and locate it on the mounting bracket or the top fixing screws when piping from above.

2. Adjust the position of the boiler, as necessary. Fit the bottom screws to secure the boiler in position (do not forget to tighten the top screws when piping from above).

4.5 CONNECT THE PIPEWORK - Fig. 11

1. Thoroughly flush out all the water pipework. Note: Ensure that all the plastic caps are removed from the boiler connections.

2. Secure all the valves/fittings to the boiler- use the washers supplied, ensuring they are facing the rear wall. Fit the union bends to the valves. Note: 1. If soldering to the boiler union bends, ensure the bends are not connected to the valves, otherwise the internal

seals may be damaged.

2. Ensure the 22 mm isolating valve with the filter is fitted to the heating return connection. (Refer to Fig. 11).

3. Fit the pressure relief valve connection before the isolating valves.

3. Connect the system pipework to the boiler. Note: Do not forget that the pressure relief valve discharge pipe must be routed clear of the boiler to a drain in such a manner that it may be seen, but cannot cause injury to persons or property.

4. Ensure that all the valves are closed (spindle flats at right angles to valve) and do not turn on the water or gas supplies at this stage.

Alpha 240/280 - Installation

Note: Disconnect the filling loop after filling the central heating system.

A - Heating flow (22 mm) B - Hot water outlet (15 mm) C - Gas inlet (22 mm) D - Cold water mains inlet (15 mm) E - Heating return (22 mm) F - Pressure relief valve (15 mm)

Note: Both Heating return and Cold water

mains inlet valves contain serviceable filters.

Filling loop

20 23

95 65 65 65 65 55

ABCDEF

Fig. 11

4.6 FIT THE FLUE - Figs. 12, 13

1. The following procedure applies to both rear or side exit flue. The only difference being the lengths to which the ducts are cut. Rear flue Outer air duct length = finished wall thickness + 110 mm.

Inner flue duct length = finished wall thickness + 147 mm.

Side flue Outer air duct length = finished wall thickness + the distance from the inside wall to the side of the boiler + 145 mm.

Inner flue duct length = finished wall thickness + the distance from the inside wall to the side of the boiler + 182 mm.

2. If the overall length of the inner duct is greater than 750 mm then a flue extension is required. To fit an extension refer to the following section.

3. Withdraw the inner flue duct from the outer air duct.

4. Mark the outer air duct to match the length given above, measure from the end of the tube as shown in Figs. 12 and 13.

5. Mark the inner flue duct to match the length given above.

6. Cut both the inner and outer ducts to length. Note: Do not cut the outer duct end with the two holes, these are for securing the terminal. Ensure that all cuts are square and burr free.

7. Fit the flue terminal to the outer duct by inserting it into the end with two holes. Align the holes and secure with the two screws provided.

8. Place the inner flue duct back into the outer duct.

9. Pass the flue assembly through the wall (from inside or outside). Note: Internal fitting - If there is no access to make good the outside wall, locate and secure the flue sealing collar onto

the outer duct of the flue immediately before the terminal. Push the flue assembly through the 127 mm flue hole, so that the collar completely passes through the wall. Then pull the flue assembly back into the correct position. Visually check that the collar is sealing the outside wall and that it is not restricting any of the openings of the flue terminal.

10. Position the seal and clamp (two screws), supplied with the bend, over the boiler flue adaptor. Fit the bend and rotate to the correct position, then secure in position. See Fig 12. Note: Ensure that the seal is located over both the bend and the flue adaptor.

11. Place the inner (no seal) duct clamp in position over the bend outlet as shown in Figs. 12 and 13, and position the outer duct seal over the bend.

12. Push the outer duct into the wall slightly at the same time as pulling the inner duct towards the bend, inserting it fully into the clamp on the bend. Tighten the clamp to secure the inner duct. Note: Ensure the inner duct clamp screwed joint is at the bottom.

13. Pull the outer duct towards the bend. Check that the flue terminal protrudes 120 mm out of the wall, then position the seal equally over the joint between the bend and the outer duct. Dismantle the clamp, position it over the seal and secure in position.

14. Make good the inside and outside walls. The flue sealing collar could be used for making good either the outside or inside by locating it over the outer duct of the flue and pushing it tight against the wall. If fitting the collar externally, ensure it does not restrict any of the openings of the flue terminal.

Alpha 240/280 - Installation

120

Inner flue duct length

Outer air duct length

120

Terminal

Flue sealing collar

Note: For horizontal flue ensure there

is a slight downward slope towards terminal.

190

Outer duct clamp and seal

Inner duct clamp

90° bend

Ensure joint of inner

Boiler

clamp is at bottom

Fig. 12 - Rear flue

Outer duct clamp

and seal

Seal

Inner duct clamp

125

Bend clamp and seal

Restrictor (N/A to 280E/P)

Screw

Boiler

225

Outer air duct length

Inner flue duct length

225

Fig. 13 - Side flue

4.7 FIT A FLUE EXTENSION - Figs. 12, 13

Note: 1. The maximum flue assembly length must not exceed a length of 4 metres.

2. If the flue is more than 1 m, the restrictor must be removed from the flue adaptor (see Fig. 13), by removing the screw

and lifting out the restrictor. The Alpha 280E and 280P are not fitted with a restrictor.

1. Withdraw the inner flue duct from the outer air duct supplied with the boiler.

2. Withdraw the inner flue duct from the extension. Secure the two ducts together using the clamp supplied with the extension, ensure that the ducts are butted together and the clamp is central over the joint.

3. Secure the outer ducts together using the silicone seal and clamp supplied with the extension. Lubricating the silicone seal with a soap solution will aid assembly.

4. With all the ducts assembled together, cut to the following lengths:Rear flue Outer air duct length = finished wall thickness + 110 mm.

Inner flue duct length = finished wall thickness + 147 mm.

Side flue Outer air duct length = finished wall thickness + the distance from the inside wall to the side of the boiler + 145 mm.

Inner flue duct length = finished wall thickness + the distance from the inside wall to the side of the boiler + 182 mm.

5. When measuring the outer duct, measure from the end of the tube as shown in Figs. 12 and 13.

6. Cut both the inner and outer ducts to length. Note: Do not cut the outer duct end with the two holes, these are for securing the terminal. Ensure that all cuts are square and burr free.

7. Fit the flue terminal to the outer duct by inserting it into the end with two holes. Align the holes and secure with the two screws provided.

Alpha 240/280 - Installation

8. Place the inner flue duct back into the outer duct. Use the inner duct supports to centralise the duct in the outer duct.

9. Fit the flue assembly as described in the previous section. Due to the size of the flue clamps the flue must be fitted from inside the building.

10. It may be necessary to support the flue with suitable brackets (every metre) when flue lengths approaching the maximum are used.

4.8 CONNECT THE MAINS SUPPLY - Fig. 14

Terminal block cover

1. Gain access to the boiler terminal block by lowering the front

Remove link to connect external control

cover and removing the two fixing screws (one each side) securing the control panel. Close the front cover, raise the complete control panel slightly, hinging it forward at the same time. Refer to Technical Data, section 2.9 for connection details.

2. Note: This boiler has been fitted with a mains supply cable.

Fuse F2A

Cable clamps

However, if it is necessary to fit an alternative supply cable, ensure the cable clamp that has been fitted is removed and connect as follows:Remove the screw securing the terminal block cover from the back of the control box (see Fig. 14). Pass the mains supply cable through the cable clamp and connect as follows:- Brown to L,

Blue to N and Green/Yellow to

. Ensure correct polarity. Note: Ensure that the length of the earth wire is such that if the supply cable is pulled out of its clamp the live and neutral wires become taut before the earth wire.

Fig. 14

The main terminal block can be removed by pulling it off the pins to give easy access to the terminals. Do not switch on the electrical supply at this stage.

3. If an external control, i.e. room thermostat or external clock is to be fitted, remove the terminal block cover and remove the link between terminals 1 and 2. Pass the cable through the cable clamp, through the grommet (cut as necessary) and connect it to terminals 1 and 2. Replace the terminal block cover. (Refer to section 2.9).

4. Replace the terminal block, ensuring it is located correctly on the plastic pins and replace the cover.

5. Ensure that there is sufficient free cable to allow the control panel to be raised and lowered then tighten the cable clamp screws.

6. Leave the control panel open until commissioning procedures have been completed.

7. Carry out electrical system checks - Short circuit, Polarity, Earth continuity and Resistance to earth with a suitable multimeter.

4.9 FIT THE CLOCK KIT - Fig. 15

Ensure the electrical supply to the boiler is isolated.

1. Remove the five screws securing the rear cover of the control panel and carefully raise the cover from the front.

2. Remove and discard the clock blanking panel.

3. Insert the clock into the opening and secure in place with the screws supplied.

4. Disconnect the clock wiring from the terminal block and connect it to the clock as follows:Blue wire to terminal 1, Brown wire to terminal 2 and Black wires to terminals 3 and 4, (or as per the instructions supplied with the clock). Ensure wiring is correct.

5. Replace the rear cover, ensure no wires are trapped and all wiring grommets are in position. Do not overtighten the fixing screws.

6. Leave the control panel open until commissioning procedures have been completed.

Clock

Control panel

Terminal without clock fitted

Fig. 15

Alpha 240/280 - Installation

5 COMMISSIONING

When commissioning the boiler, ensure the Benchmark Log Book is completed.

5.1 FILL THE SYSTEM

1. The boiler is fitted with an automatic air vent positioned on the pump (see Fig. 2 or 3). The vent is fitted with a non-sealing cap.

2. Open the central heating flow and return valves (spindle flats in-line with valve) (see Fig. 11).

3. Open the fill point valve on the filling loop until water is heard to flow. To aid venting, the boiler drain point (see Fig. 35) may be opened until water flows out. Close the drain point as soon as water appears.

4. To remove the air - Vent each radiator in turn, starting with the lowest in the system.

5. It is important that the pump is properly vented to avoid it running dry and damaging its bearings. Unscrew and remove the cap from the centre of the pump. Using a suitable screwdriver rotate the exposed spindle about half a turn, then replace the cap.

6. Check the operation of the pressure relief valve (see Fig. 35) by turning the head anti-clockwise until it clicks. The click is the valve lifting off its seat allowing water to escape from the system - check that this is actually happening.

7. Continue to fill the system until the pressure gauge indicates 1.0 bar. Close the fill point valve and check the system for water soundness, rectifying where necessary. Disconnect the filling loop from the mains supply. Water may be released from the system by manually operating the drain point (see Fig. 35) until the system design pressure is obtained. The system design pressure (cold) should be between 0.75 and 1.25 bar.

Refer to sections 3.7 and 3.8. System volume and Filling the system.

8. Open the mains water inlet valve (see Fig. 11). Turn on all hot water taps and allow water to flow until no air is present. Turn off taps.

5.2 BOILER CONTROLS - Fig. 16

Alpha 240P and 280P

THERMOSTAT0THERMOSTAT SELECTOR GAS

Central Heating Thermostat

Domestic Hot Water Thermostat

Alpha 240E and Alpha 280E

Selector Switch

Gas Control

Pilot and Burner Viewing Window

OFF

Indicator Neons

Burner Viewing Window

bar

System Pressure Gauge

Clock (if fitted)

Central Heating Thermostat

Alpha 240/280 - Commissioning

THERMOSTAT0THERMOSTAT0SELECTOR

Domestic Hot Water

Selector Switch

Thermostat

Fig. 16

RESET

White Reset Button

RESET

Indicator Neons

bar

Red Reset Button

Clock (if fitted)

System Pressure Gauge

5.3 TEST FOR GAS SOUNDNESS AND PURGE THE SUPPLY

1. With the boiler gas service cock closed (spindle flats at right angles to valve). Pressure test the gas supply and inlet pipework connection to the boiler gas service cock for soundness in accordance with BS 6891.

2. Loosen the gas inlet pressure test point screw on the gas valve (see Fig. 17). Ensure the gas supply is on and open the boiler service cock to purge in accordance with BS 6891.

3. Retighten the test point screw and test for gas soundness. Close the boiler gas service cock.

5.4 INITIAL LIGHTING - Refer to Fig. 16

Note: Remove the protective plastic coating from the boiler painted panels before lighting.

1. Ensure that the gas and electrical supplies to the boiler are off and that the mains water inlet valve and the central heating flow and return valves are open.

2. Turn on the gas and electrical supplies to the boiler.

3. Ensure all external controls are calling for heat. If the optional Clock is fitted, refer to the User's instructions, set the time and ensure the Clock is in an 'on' mode.

4. Set the hot water and central heating temperature selectors to maximum.

5. Set the selector switch to

(DHW only), the electrical supply neon will illuminate.

240Pand 280P only - Light the pilot Depress the gas valve control, allowing gas to the pilot. The micro switch on the gas valve is switched on when the control is depressed. The fan will operate at full speed. When the air pressure switch is proved, after a delay of about 10 seconds, a spark will light the pilot.

Warning: If the pilot does not stay alight, release the gas control and turn it clockwise (about ¼ turn). Wait 3 minutes and repeat lighting procedure.

When the pilot remains alight, continue to hold the gas control in for a further 20 seconds, then release it: the pilot should remain alight and can be viewed through the window in the room sealed chamber panel. When the gas control is released, the fan goes to slow speed.

6. Open a hot water tap, the main burner will light and the boiler will provide hot water. Close the tap and the burner will go out.

7. Set the selector switch to in the central heating mode. The pump will start, the fan will start; once the pressure switch is proved, the main gas valve solenoid will open

(CH and DHW). The boiler will now run

Burner pressure test point

allowing the main burner to light from the ignition electrodes, or pilot in the case of the Alpha 240P and 280P boilers.

Inlet gas pressure test point

5.5 CHECK THE BURNER PRESSURES - Fig. 17 or 17A

Turn the boiler off. Loosen the burner pressure test point screw on the gas valve and connect a pressure gauge. Allow the boiler to run for 10 minutes and check the burner pressures.

Hot water mode

1. Set the selector switch to

2. The burner will light at the ignition rate and the burner pressure will increase to maximum.

(DHW only) and fully open a hot water tap.

Fig. 17 - Alpha 240E and 280E

3. Gradually close the hot tap and check that the burner pressure decreases to its minimum. Fully open the tap and check that the burner pressure increases. Close the tap and check that the burner goes off. The burner pressure settings have been factory set and do not require adjusting. If incorrect, check that the inlet gas pressure is 20 mbar. If the inlet gas pressure is not 20 mbar, either the pipework is too small or the gas supply to the house is insufficient, in which case contact your gas supplier.

Central heating mode

Burner pressure test point

1. Set the selector switch to (DHW and CH).

2. The burner will light at the ignition rate and will increase to the factory pre-set maximum output.

3. Turn off the boiler. Disconnect the pressure gauge and tighten the test point screw.

Test for gas soundness using suitable leak detection fluid.

Inlet gas pressure test point

Note: Refer to Technical Data, section 2.1 for burner pressure settings.

Fig. 17A - Alpha 240P and 280P

Alpha 240/280 - Commissioning

5.6 FINAL COMMISSIONING

1. Allow the heating system to heat up, then balance the system to achieve the necessary temperature difference across the heating flow and return pipes at the boiler and check the system volume and pressure. (Refer to Technical Data, sections

2.8 and 2.10).

2. Turn off the boiler.

3. Thoroughly flush out the water pipework and clean the filters in the heating return and mains water inlet isolating valves.

4. Re-pressurise the system as described in section 5.1.

5.7 FINAL ASSEMBLY

1. Raise the control panel and secure in position with the screws previously removed. Alpha 240P and 280P only - Ensure the gas control locates correctly over the black cap on the gas valve knob.

2. Place the front casing in position over the boiler ensuring the bottom is located behind the control panel and secure in position at the top using the screws previously removed.

3. If the boiler is to be left in service with the User, set the controls, clock (if fitted, see User's Operating manual) and room thermostat (if fitted) to the User's requirements.

4. If the boiler is not to be handed over immediately, close the boiler gas service cock and switch off the electrical supply.

5. If there is any possibility of the boiler being left during frost conditions, then the boiler and system should be drained (refer to section

8.2). It is recommended that a label is attached to the boiler drawing attention to the fact that the system has been drained.

6. Complete the details of the installation on the back page of this manual.

5.8 USER INFORMATION

The User must be advised (and demonstrated if necessary) of the following important points:-

1. How to light and turn off the boiler and how to operate the system controls.

2. The importance of annual servicing of the boiler to ensure safe and efficient operation.

3. That any servicing or replacement of parts must only be carried out by CORGI registered personnel.

4. Ensure that the boiler controls and room thermostat (if fitted) are set to the User's requirements.

5. Tell the User about the sealed system pressure.

6. Tell the User that if the electrical supply neon hot water, the pump will automatically operate for 5 minutes.

7. Explain to the User that an internal frost thermostat is fitted in the boiler, and that elecrical supply to the boiler must be left on (electrical supply neon operate.

8. Show the User the position of the pressure relief valve discharge pipe.

9. Hand the User's instructions and the Benchmark Log Book to the User.

10. Leave these Installation and Servicing instructions with the User for use on future calls.

illuminated), and for the Alpha 240P and 280P boilers, the pilot is alight, for the thermostat to

is illuminated and the boiler has not operated for 24 hours for heating or

6 BOILER OPERATION

The boiler operating mode is controlled by the selector switch on the facia panel. When set to , the boiler will only operate in the Domestic Hot Water mode. When set to , it will operate in the Domestic Hot Water and Central Heating mode.

Note: The clock (if fitted) only controls the operating times of the central heating, not domestic hot water - DHW is available continuously. Domestic hot water supply always takes priority over central heating. If a demand for hot water is required during a central

heating period, the boiler will automatically switch to the hot water mode until the demand is satisfied. This interruption in the central heating is only when the demand for hot water is present and should not be noticed by the User.

6.1 CENTRAL HEATING MODE

If there is a call for heat, the pump will start to circulate the central heating water, operating the flow switch. The fan will run at full speed; once the air pressure switch is proved the burner will light. The burner output then automatically adjusts to suit the system demand; as the temperature of the water in the boiler approaches that set by the adjustable temperature selector, the burner output is reduced. When the set temperature is reached, the burner is turned off and the fan stops (the fan drops to low speed on the Alpha 240P and 280P). The pump continues to run for five minutes to remove residual heat build up in the boiler. The burner will not relight for 3 minutes. If the CH sensor has not registered the pre-set temperature but the room thermostat is satisfied the burner is turned off, the fan stops (the fan drops to low speed on the Alpha 240P and 280P) and the pump continues to run for five minutes. In this instance there is no 3 minute delay before the burner will relight.

If there is a demand for DHW during the 3 minute burner delay, the boiler will operate to provide DHW until the tap is closed; the boiler will then immediately revert to provide CH if there is a demand.

Alpha 240/280 - Commissioning/Boiler Operation

6.2 DOMESTIC HOT WATER MODE

When a demand for hot water (by opening a hot tap, etc.) is sensed by the flow switch, the pump starts and the burner lights at its middle output, increasing to its maximum output. Water in the boiler is then diverted from the central heating system to the domestic hot water heat exchanger, heating the incoming mains water. The burner output is varied to maintain the temperature of the hot water as that set by the adjustable temperature selector. When the flow switch senses that hot water is no longer required the burner is turned off and the boiler immediately returns to the central heating mode.

In both modes the fan operates at full speed before the burner lights, remaining at that speed until the demand is satisfied.

6.3 FROST THERMOSTAT

The boiler incorporates a built in frost thermostat which automatically turns on the boiler and pump if the water in the boiler falls below 5°C, providing the electrical supply neon the water temperature in the system reaches approximately 30°C.

is illuminated and, if applicable, the pilot is alight. The boiler will operate until

6.4 PUMP

If the electrical supply neon is illuminated and the boiler has not operated for 24 hours for heating or hot water, the pump will operate automatically for five minutes every 24 hours.

6.5 INDICATOR NEONS

When illuminated, the following conditions apply:-

Warning light (continuously on) - blocked flue or fan fault, contact your Service Engineer.

Overheat thermostat has operated - press white reset button (see Fig. 16) to reset (not applicable to the Alpha 240Pand 280P).

Electrical supply to the boiler is on. Boiler is supplying hot water. Boiler is supplying central heating.

When the red reset button ( Fig. 16) and the ignition sequence will restart (not applicable to the Alpha 240P and 280P).

) is illuminated it indicates that the burner has failed to light - Press the red reset button (see

7 ROUTINE SERVICING

To ensure efficient operation of the boiler it is recommended that it is checked and serviced as necessary at regular intervals. The frequency of servicing will depend upon the particular installation conditions and usage, but in general once per year should be adequate.

It is the law that any service work must be carried out by a competent person, ie CORGI registered personnel.

7.1 IMPORTANT NOTES PRIOR TO SERVICING

1. Check the flue terminal outside and ensure it is not blocked.

2. Run the boiler and check the operation of its controls.

3. Refer to Fig. 2 or 3 for location of flue sampling point.

4. Ensure that all system connections and fittings are sound. Remake any joints and check the tightness of any fittings that may be leaking.

5. It is recommended that the operation of the safety valve is checked by turning the head anti-clockwise until it clicks. The click is the safety valve lifting off its seat allowing water to escape from the system - check that this is actually happening.

6. Refill, vent and re-pressurise the system as necessary. (Refer to Commissioning, section 5.1). If the system pressure exceeds 2.5 bar when operating at maximum temperature, the heating expansion vessel should be checked and re-pressurised, if necessary.

Note: 1. Check the expansion vessel charge only when the system pressure is zero.

2. The expansion vessel pressure test point is accessible from the top and rear of the boiler.

7. Record details of the service in the Service History section on the back page of this manual.

Warning: Before servicing the boiler, isolate the electrical supply and close the boiler gas service cock. Allow the boiler to cool. The data label is positioned on the right hand case side panel and is visible after removing the front casing. Always test for gas soundness after servicing any gas carrying components.

Alpha 240/280 - Boiler Operation/Routine Servicing

7.2 PREPARE FOR SERVICING - Fig. 18

1. Ensure the electrical supply is isolated and the gas supply is off.

2. Remove the two screws securing the top of the front casing. Lift the cover up slightly and remove.

3. Remove the four screws securing the room sealed chamber panel and remove the panel, taking care not to damage the seal.

4. Lower the front cover and remove the two fixing screws (one each side) securing the control panel. Close the front cover, raise the complete control panel slightly, hinging it forward at the same time.

5. Alpha 240E and 280E - Disconnect the electrode leads from the electrodes. Alpha 240P and 280P - Disconnect the thermocouple and pilot supply from the gas valve. Remove the two screws securing the pilot assembly to the burner. Remove the pilot shield and withdraw the complete pilot assembly.

6. Remove the five screws securing the combustion chamber front cover and remove the cover.

7. Withdraw the main burner out of the boiler. Take care not to damage the side insulation panels. Alpha 280E and 280P - Remove the two screws securing the burner.

Front casing screws

Room sealed

chamber

panel screws

Flame sensing electrode

(240E/280E)

Combustion chamber front cover

Ignition electrodes

(240E/280E)

Alpha 240P/280P

Pilot assy.

Control panel

screws

Thermocouple and pilot supply

Fig. 18

7.3 CLEANING THE BOILER

1. Remove any deposits from heat exchanger using a suitable soft brush. Do not use a brush with metallic bristles.

2. Check the condition of the combustion chamber insulation panels. Any damaged panels must be replaced. (Refer to Component Replacement, section 8.23).

3. Check the condition of the burner injectors on the manifold, carefully clean them with a soft brush if necessary. Do not use a brush with metallic bristles as this might damage the injectors.

4. Remove any fallen deposits from the bottom of the inner case.

5. Unscrew and replace any injector that appears damaged.

6. Clean the top of the burner with a soft brush and check that the flame ports are clear. Blockages may be removed with a stiffer brush. Tap the burner, open end down, to remove any deposits from inside.

7. Alpha 240E and 280E - Check the condition of the electrodes. Alpha 240P and 280P - Check the condition of the pilot assembly, removing any carbon deposits from the thermocouple

tip. Disconnect the pilot supply from the pilot burner, carefully withdraw it and remove the injector. Check the condition of the pilot injector and clean if necessary. Refit the pilot injector over the pilot supply and reconnect it to the pilot burner (see Fig. 18).

9. Check the spark gap, positioning and height of the electrodes (see Figs. 19 and 20).

10. Check that the fan impeller is clean and free to rotate.

Alpha 240/280 - Routine Servicing

7.4 RE-ASSEMBLE THE BOILER

1. Replace the burner, ensuring it is located correctly over the injectors and the four locating pins (two each side).

2. Replace the combustion chamber front cover, ensuring the bottom is correctly located in the burner.

3. Alpha 240E and 280E - Ensure the electrode leads are connected and the seals are in position in the bottom of the inner case. Alpha 240P and 280P - Refit the pilot assembly and pilot shield to the burner. Ensure the ignition lead is still connected

and the seal is in position in the bottom of the inner case. Reconnect the pilot supply and thermocouple

4. Test the connections for gas soundness and check the burner pressures. (Refer to Commissioning, sections 5.4 and 5.5).

5. Ensure that the room sealed chamber panel seal is intact and in position, replace the panel and secure it in position with the screws previously removed.

6. Raise the control panel and secure in position with the screws previously removed.

7. Place the front casing in position over the boiler ensuring the bottom tags are located behind the control panel and secure in position at the top using the screws previously removed.

8. Check the operation of the boiler. (Refer to Boiler Operation, section 6).

9. Return all controls to their original settings.

8 COMPONENT REPLACEMENT

It is the law that any service work must be carried out by a competent person, ie CORGI registered personnel. Warning: Before replacing any boiler components, isolate the electrical supply and close the boiler gas service cock. Allow the

boiler to cool. Always test for gas soundness after replacing any gas carrying components or disturbing any gas connections. Check the operation of the boiler. (Refer to Boiler Operation, section 6). Ensure that all the controls are returned to their original settings. The replacement of components in sections 8.3 to 8.21 does not require draining of the boiler.

8.1 GENERAL ACCESS - Fig. 17

Ensure the electrical supply is isolated and the gas supply is off. Remove the two screws securing the top of the front casing. Lift the cover up slightly and remove.

1. If access is required behind the control panel - Lower the front panel and remove the two fixing screws (one each side) securing the control panel. Close the front cover, raise the complete control panel slightly, hinging it forward at the same time. Alpha 240P and 280P - When replacing the control panel, ensure that the gas control locates correctly over the black cap on the gas valve knob.

2. To gain access to the combustion chamber - Remove the four screws securing the room sealed chamber panel and remove the panel, taking care not to damage the seal. When replacing the panel, ensure the seal is intact and in position.

3. To gain access to the control panel components - Remove the five screws securing the rear cover and carefully raise the cover from the front. When replacing the cover, ensure no wires are trapped and all wiring grommets are in position. Secure with five screws - do not overtighten.

8.2 DRAINING THE BOILER - Refer to Figs. 2 or 3, 11

Isolate the electricity supply and close the boiler gas service cock (see Fig. 11). Allow the boiler to cool. Remove the two screws securing the top of the front casing. Lift the cover up slightly and remove. Lower the front cover and remove the two fixing screws (one each side) securing the control panel. Close the front cover, raise

the complete control panel slightly, hinging it forward at the same time.

1. Heating circuit Close the central heating flow and return valves (see Fig. 11). Connect a suitable pipe to the drain point (see Fig. 2 or 3) and route it to a suitable container. Open the drain tap.

2. Hot water circuit Close the mains water inlet valve (see Fig. 11). Open any hot tap below the level of the boiler to allow as much draining as possible.

Note: Some water will remain in the components and care must be taken when removing them.

Alpha 240/280 - Routine Servicing/Component Replacement

8.3 PILOT COMPONENTS (Alpha 240P and 280P only) - Fig. 19

Gain access as in section 8.1. Disconnect the thermocouple and pilot supply from the gas valve. Remove the pilot assembly from the burner.

1. Thermocouple Disconnect from the pilot burner and withdraw through the grommet. Carefully bend new thermocouple to match the old one, pass it through the seal and connect to the pilot burner.

2. Electrode Disconnect the lead from the electrode, unscrew the nut and withdraw the electrode. It will be necessary to remove the thermocouple first. Fit the new electrode and check the spark gap (see Fig. 19).

3. Pilot injector Disconnect the pilot supply and remove the injector. Fit the new injector over the pilot supply as shown in Fig. 19, and reconnect it to the pilot burner.

Re-assemble

1. Replace the pilot assembly and pilot shield then reconnect the pilot supply and thermocouple to the gas valve. Ensure that the overheat thermostat connection is in position in the gas valve before securing the thermocouple.

2. Light the boiler and test the pilot supply for gas soundness. (Refer to Commissioning, section 5.4).

3. Complete re-assembly as described in Routine Servicing, section 7.4 paragraphs 5 to 9.

Pilot burner

Pilot shield

Thermocouple Electrode

Pilot injector

5 mm

Spark gap

Fig. 19

8.4 IGNITION LEAD (Alpha 240P and 280P only) - Refer to Fig. 28

1. Gain access as in section 8.1.

2. Disconnect the lead from the electrode.

3. Disconnect the lead from the ignition PCB (see Fig. 28).

4. Fit the new lead ensuring it passes through the grommets in the control panel cover and base of the combustion chamber.

5. Re-assemble in reverse order.

8.5 IGNITION ELECTRODE LEAD (Alpha 240E and 280E only) - Refer to Fig. 27

1. Gain access as in section 8.1.

2. Disconnect the lead from the electrodes.

3. Disconnect the lead from the ignition PCB, noting its position (see Fig. 27).

4. Fit the new lead ensuring it passes through the grommets in the control panel cover and base of the combustion chamber.

5. Re-assemble in reverse order.

Alpha 240/280 - Component Replacement

8.6 ELECTRODES (Alpha 240E and 280E only) - Fig. 20

Gain access as in section 8.1.

1. Remove the five screws securing the combustion chamber front cover and remove the cover.

2. Disconnect the leads from the electrodes.

3. Withdraw the main burner out of the boiler. Take care not to damage the side insulation panels.

4. Flame sensing electrode Remove the screw securing the electrode and withdraw the electrode. Fit the new electrode, ensuring it is positioned correctly (see Fig. 20).

5. Ignition electrodes Remove the screws securing the electrodes and withdraw the electrodes. Fit the new electrodes, ensuring they are positioned correctly and the spark gap is correct (see Fig. 20).

Re-assemble

1. Replace the burner, ensuring it is located correctly over the injectors and the four locating pins (two each side).

2. Replace the combustion chamber front cover, ensuring the bottom is correctly located in the burner.

3. Complete re-assembly as described in Routine Servicing, section 7.4 paragraphs 4 to 9.

1.2 to 3.5 mm

Flame sensing electrode

2.5 to 3.5 mm

Ignition electrodes

Securing

screws

Fig. 20

8.7 MAIN BURNER

1. Remove the burner as described in Routine Servicing, section 7.2.

2. Re-assemble with a new burner as described in Routine Servicing, section 7.4.

8.8 BURNER INJECTORS

1. Remove the burner as described in Routine Servicing, section 7.2.

2. Unscrew the damaged injector and screw in a replacement.

3. Re-assemble as described in Routine Servicing, section 7.4.

Alpha 240/280 - Component Replacement

8.9 FAN - Fig. 21

1. Gain access as in section 8.1.

2. Remove the five screws securing the combustion chamber front cover and remove the cover.

3. Disconnect the air pressure tubes from the fan outlet.

4. Loosen the fan to flue adaptor clamp screws and raise the clamp as far as possible.

5. Remove the two screws securing the flue hood to the back panel and withdraw the assembly sufficiently to disconnect the fan wiring.

6. Remove the four screws securing the fan to the flue hood. Transfer the fan outlet casing to the new fan and reassemble in reverse order. Alpha 240E and 280E - Connect the fan wiring, blue to terminal 1 and brown to terminal 2. Alpha 240P and 280P - Connect the fan wiring, blue to terminal 4, brown to terminal 3 and black to terminal 1. Ensure the pressure tubes are connected correctly (see Fig. 21). ( and + marked on the fan outlet), and that the bottom of the combustion chamber cover is located in the burner.

7. Re-assemble and test the boiler as described in Routine Servicing, section 7.4 paragraphs 5 to 9.

Flue

hood

screws

Fig. 21

Flue spigot clamp

Pressure sensing tubes

Air pressure switch connections

Combustion chamber front screws

8.10 AIR PRESSURE SWITCH - Fig. 22

1. Gain access as in section 8.1, remove the five screws securing the combustion chamber front cover and remove the cover.

2. Disconnect the pressure sensing tubes.

3. Remove the two fixing screws and disconnect the wiring.

4. Connect the wiring to the new switch, black to C, brown to NC, blue to NO and reconnect the pressure tubes (see Fig. 22).

5. Secure the new switch in position.

6. Re-assemble in reverse order.

8.11 OVERHEAT THERMOSTAT - Fig. 23

1. Gain access as in section 8.1.

2. Alpha 240E and 280E - Disconnect the wiring from the overheat thermostat. Alpha 240P and 280P - Disconnect the thermocouple from the gas valve and withdraw the overheat thermostat lead.

Unscrew the other overheat thermostat lead from the back of the gas valve - accessible from the boiler base.

3. Remove the two fixing screws and remove the overheat thermostat from the CH flow pipe.

4. Fit the new overheat thermostat and re-assemble in reverse order.

Overheat thermostat

(Black wire) C

(Brown wire) NC

Pressure sensing tubes

NO (Blue wire)

Thermostat lead connections

(240P and 280P)

Fig. 22 Fig. 23

Alpha 240/280 - Component Replacement

8.12 GAS VALVE (Alpha 240P and 280P only) - Fig. 24

1. Gain access as in section 8.1.

Pilot supply

2. Disconnect the thermocouple, pilot supply and overheat thermostat leads from the gas valve.

Thermocouple

3. Disconnect the wiring and pressure tube from the gas valve.

4. Remove the screw securing the light grey cover around the gas control knob.

5. Remove the screw securing the microswitch assembly to the valve (access from beneath the

Modulating coil spring clip

boiler).

6. Remove the four manifold screws from beneath the boiler.

7. Disconnect the burner manifold union underneath the room sealed chamber.

8. Carefully push the valve towards the rear of the boiler (take care not to damage the manifold sealing washer) and lift out the valve assembly.

9. Remove the burner manifold pipe and fit it to the new valve using the new 'O' ring seal supplied.

10. Fit the new assembly, using the new 'O' ring supplied in the bottom of the gas valve.

Grey cover screw

Ignition microswitch assembly

Fig. 24

11. Remove light grey cover from the new valve and fit the microswitch assembly. Replace the cover (ensure the operating arm is located under the cover).

12. Re-assemble in reverse order.

13. Light the boiler and test for gas soundness. (Refer to Commissioning, section 5.4).

14. Complete re-assembly as described in Routine Servicing, section 7.4 paragraphs 5 to 9.

Burner manifold union

Overheat thermostat leads

Room sealed chamber pressure tube

Manifold screws

8.13 GAS VALVE (Alpha 240E and 280E only) - Fig. 25

1. Gain access as in section 8.1.

2. Disconnect the coil wires and pressure tube from the gas valve.

Room sealed chamber pressure tube

3. Loosen the one screw (see Fig. 25) securing the solenoid plug and disconnect the plug.

4. Remove the two manifold screws from beneath the boiler.

5. Disconnect the burner manifold union underneath the room sealed chamber and the gas inlet pipe union from the manifold.

6. Carefully push the valve towards the rear of the boiler (take care not to damage the manifold sealing washer) and lift out the valve assembly.

7. Remove the burner manifold pipe and fit it to the new valve using the new 'O' ring seal supplied.

Screw

Solenoid plug

8. Remove the gas inlet manifold and fit to the new valve using the new 'O' ring seal supplied.

9. Fit the new assembly and re-assemble in reverse order.

10. Light the boiler and test for gas soundness. (Refer to Commissioning, section 5.4).

11. Complete re-assembly as described in Routine Servicing, section 7.4 paragraphs 5 to 9.

Fig. 25

Burner manifold union

Manifold screws

8.14 GAS VALVE MODULATING COIL - Refer to Fig. 24 or 25

1. Gain access as in section 8.1.

2. Disconnect the wires from the coil and remove the spring clip.

3. Lift off the coil and re-assemble in reverse order with a new coil. The polarity of the wires is not important.

Modulating coil spring clip

Modulating coil

Alpha 240/280 - Component Replacement

8.15 IGNITION MICROSWITCH ASSEMBLY (Alpha 240P and 280P only) - Figs. 26 and 28

1. Gain access as in section 8.1.

2. Remove the screw securing the light grey cover around the gas control knob.

3. Remove the screw securing the microswitch assembly to the valve (access from boiler base).

4. Remove the 2-pin connector from the ignition PCB and remove the microswitch complete with cable.

5. Re-assemble in reverse order.

8.16 VIEWING WINDOW

1. Gain access as in section 8.1.

2. Remove the two screws securing the window frame and remove the damaged glass and gasket.

3. Re-assemble in reverse order with a new glass and gasket. Ensure the gasket is next to the inner case front panel.

Ignition microswitch assembly

8.17 INTERNAL FUSE - Refer to Fig. 14

The fuse is located in the boiler terminal block.

1. Gain access as described in Installation, section

4.8.

2. Lift out the fuse holder and remove the fuse. Fit a fast blow 2 A fuse as a replacement, ensuring that the holder snaps into position.

3. Re-assemble in reverse order, ensuring the terminal block is located correctly on the plastic pin.

Grey cover screw

Microswitch assy. screw

Fig. 26

8.18 IGNITION PCB (Alpha 240E and 280E only) - Refer to Fig. 27

1. Gain access as described in section 8.1.

2. Disconnect the wiring connectors, then remove the four fixing screws.

3. Connect the wiring to the new PCB and re-assemble in reverse order.

8.19 NEON ASSEMBLY (Alpha 240E and 280E only) - Refer to Fig. 27

1. Gain access as described in section 8.1.

2. Remove four screws securing ignition PCB.

3. Remove two screws securing neon PCB and disconnect the two wiring connectors from the main PCB.

4. Re-assemble in reverse order.

8.20 RELAY PCB - Refer to Fig. 27 or 28

1. Gain access as described in section 8.1.

2. Disconnect the wiring connector from the PCB.

3. Remove the fixing screw and remove the board.

4. Re-assemble in reverse order.

8.21 RESET SWITCH (Alpha 240E and 280E only) - Refer to Fig. 27

1. Gain access as described in section 8.1.

2. Disconnect the wiring from the switch.

3. Depress the switch retaining lugs and withdraw the switch from the front of the control panel.

4. Re-assemble in reverse order, ensuring that the wiring is connected as follows:White to terminals 1 and 3, Black to terminal 2.

Alpha 240/280 - Component Replacement

8.22 IGNITION PCB (Alpha 240P and 280P only) - Refer to Fig. 28

1. Gain access as described in section 8.1.

2. Remove the two fixing screws and disconnect the wiring.

3. Refer to Fig. 28, connect the wiring to the new PCB and re-assemble in reverse order.

8.23 NEON ASSEMBLY (Alpha 240P and 280P only) - Refer to Fig. 28

1. Gain access as described in section 8.1.

2. Remove two screws securing neon PCB and disconnect the wiring connectors from the main PCB.

3. Re-assemble in reverse order.

Neon PCB assy.

Reset switch

Relay PCB

Fig. 27 - Alpha 240E and 280E

Ignition electrode leads

Ignition PCB

Ignition lead

Ignition PCB

Neon PCB assy.

Fig. 28 - Alpha 240P and 280P

Relay PCB

Alpha 240/280 - Component Replacement

8.24 MAIN PCB - Fig. 29

1. Gain access as described in section 8.1.

2. Disconnect all the wiring connectors from the PCB.

3. Remove the four fixing screws and carefully withdraw the board from the switch spindles.

4. Re-assemble in reverse order. Refer to the Wiring Diagram on page 34 or 35 for connections.

8.25 SUPPRESSOR - Fig. 30

1. Gain access as described in section 8.1.

2. Withdraw the suppressor from the control panel cover.

3. Disconnect the wiring and re-assemble with a new suppressor. Connect the wiring as follows:Mains Brown to L2, Mains Blue to N4, Brown to U1, Blue to 3U, Green/Yellow to

Mains Brown

Brown

Fixing screws

Main PCB

Fixing screws

Fig. 29

Blue

Green/Yellow

Suppressor

Push fit Mains Blue

Rear cover of control box

8.26 DHW AND PRIMARY FLOW SWITCHES - Fig. 31

Note that both switches are the same.

1. Gain access as described in section 8.1.

2. Remove the screw securing the switch bracket to the diverter valve, disconnect the wiring and remove. Reassemble in reverse order with a new switch. Ensure that the bracket is located under the nut flange.

3. Connect the wiring as follows:PRIMARY flow switch (back of diverter valve), red wires to terminals as shown in Fig. 31. DHW flow switch (front of diverter valve), green wires to terminals as shown in Fig. 31.

8.27 CLOCK (if fitted) - Refer to Fig. 15

1. Gain access as described in section 8.1.

2. Disconnect the wiring from the clock.

3. Remove the clock retaining screws and withdraw the clock from the control panel.

4. Fit the new clock, and connect the wires as follows:Blue to terminal 1, Brown to terminal 2 and Black wires to terminals 3 and 4, (or as per the instructions supplied with the clock).

5. Re-assemble in reverse order. Refer to the User's instructions and the boiler's control cover to set the clock.

Switch bracket screw

Fig. 30

Primary flow microswitch assy.

Switch bracket screw

DHW flow microswitch assy.

Fig. 31

Alpha 240/280 - Component Replacement

8.28 HEAT EXCHANGER

1. Drain the boiler heating circuit as described in section 8.2.

2. Remove the fan and flue hood assembly as described in section 8.9.

3. Carefully prise off the two clips from the heat exchanger to flow/return pipes.

4. Lift up the heat exchanger off the pipes.

5. Fit a new heat exchanger, ensuring the 'O' rings are in position in the flanges. Lubricating the 'O' rings with a soap solution with aid assembly. Ensure the base of the heat exchanger is correctly located over the combustion chamber sides.

6. Replace the clips - narrow side to the bottom, ensuring the tops are correctly engaged in the slots.

7. Re-assemble in reverse order.

Alpha 240E and 280E - Connect the fan wiring, blue to terminal 1 and brown to terminal 2. Alpha 240P and 280P - Connect the fan wiring, blue to terminal 4, brown to terminal 3 and black to terminal 1.

Ensure the pressure tubes are connected correctly - refer to Fig. 21, and that the bottom of the combustion chamber cover is located in the burner.

8. Refill and pressurise the system. (Refer to Commissioning, section 5.1).

8.29 COMBUSTION CHAMBER INSULATION

1. Gain access as described in section 8.1.

2. Side and front panels slide out.

3. To replace the rear panel remove the heat exchanger as described in section 8.28 and slide out the side insulation panels. Prise out the top of the rear insulation panel and lift it up and out of the boiler.

4. Fit a new panel and re-assemble in reverse order.

Ensure the pressure tubes are connected correctly - refer to Fig. 21, and that the bottom of the combustion chamber cover is located in the burner.

5. Refill and pressurise the system. (Refer to Commissioning, section 5.1).

8.30 PRESSURE GAUGE - Fig. 32

1. Drain the boiler heating circuit as described in section 8.2.

2. Remove the nut securing the pressure gauge sensor to the R/H side of the diverter valve and withdraw the sensor.

3. Remove two screws securing the gauge to the control panel and withdraw.

4. Fit the new gauge using a new washer on the diverter valve connection if necessary.

5. Refill and pressurise the system. (Refer to Commissioning, section 5.1).

Pressure gauge

sensor

Fig. 32

Pressure gauge

Alpha 240/280 - Component Replacement

8.31 TEMPERATURE SENSORS - Fig. 33

Note that both sensors are the same.

1. Gain access as described in section 8.1.

2. CH Sensor - Disconnect the wiring and unscrew the sensor. Re-assemble in reverse order with a new sensor. 2a. DHW Sensor - Close the mains cold water inlet valve and open the lowest hot water tap to drain the DHW system.

Disconnect the wiring and unscrew the sensor. Re-assemble in reverse order with a new sensor, replacing the sealing washer if necessary.

8.32 AUTOMATIC AIR VENT - Fig. 33

1. Drain the boiler heating circuit as described in section 8.2.

2. Unscrew the automatic air vent from the pump outlet. Fit a new one using a new 'O' ring.

3. Refill and pressurise the system. (Refer to Commissioning, section 5.1).

8.33 PUMP - Refer to Fig. 33

Drain the boiler heating as described in section 8.2.

Pump Head

1. Remove the four socket head screws securing the pump head to the body. Withdraw the head, remove the wiring cover and disconnect the wiring.

2. Connect the wiring to the new head as follows:Brown to L, Blue to N, Green/yellow to . Ensure the pump is set to maximum (3) and re-assemble in reverse order.

3. Refill and pressurise the system. (Refer to Commissioning, section 5.1).

Complete pump

1. Unscrew the automatic air vent from the pump outlet.

2. Disconnect the pump unions and withdraw the pump, remove the wiring cover and disconnect the wiring.

3. Connect the wiring as described above, ensure that pump is set to maximum and re-assemble using new sealing washers.

4. Refill and pressurise the system. (Refer to Commissioning, section 5.1).

CH temperature

sensor

DHW temperature

sensor

Fig. 33

8.34 DHW HEAT EXCHANGER - Refer to Fig. 34

1. Drain the boiler heating and hot water circuits as described in section 8.2.

2. Remove two screws securing manifolds to heat exchanger and remove heat exchanger. Note: Be careful not to allow water to drip onto any electrical components.

3. Using the new seals supplied in the manifolds, re-assemble in reverse order. Note: Ensure the heat exchanger is fitted the right way up - see label on heat exchanger.

4. Refill and pressurise the system. (Refer to Commissioning, section 5.1).

Automatic air vent

Pump

Alpha 240/280 - Component Replacement

8.35 PRESSURE RELIEF VALVE OR DHW INLET MANIFOLD - Fig. 35

1. Remove the DHW heat exchanger as described in section 8.34.

2. Disconnect the pump unions and withdraw the pump.

3. Disconnect the pressure relief valve outlet fitting, central heating return and mains water inlet valves.

4. Disconnect the two small flow sensing pipes from the manifold, and the small by-pass pipe from the rear of the diverter valve.

5. Remove the clips (accessible from under the boiler) retaining the by-pass pipe to the manifold and diverter valve and withdraw the pipe.

6. Remove the screw securing the manifold to the chassis (accessible from under the boiler) and remove the manifold.

7. Unscrew the pressure relief valve from the manifold. Fit the replacement valve using a small amount of jointing compound. If replacing the manifold, transfer the drain point fitting to the new manifold.

8. Re-assemble in reverse order. Ensure that all seals are in good condition and in position and that the by-pass retaining clips are correctly fitted and locate in the slots.

9. Refill and pressurise the system. (Refer to Commissioning, section 5.1).

DHW expansion device connection

DHW heat exchanger

DHW heat exchanger securing screws

Pressure relief valve

Fig. 34 Fig. 35

8.36 DRAIN TAP - Fig. 35

1. Drain the boiler heating circuit as described in section 8.2.

2. Disconnect the pump unions and withdraw the pump.

3. Remove the drain tap fitting from the manifold and fit the replacement. Re-assemble in reverse order.

4. Refill and pressurise the system. (Refer to Commissioning, section 5.1).

8.37 DIFFERENTIAL PRESSURE SENSOR - Refer to Fig. 36

If required, more access may be gained by removing the pump head as described in section 8.33.

1. Drain the boiler hot water circuit as described in section 8.2.

2. Disconnect the two small flow sensing pipes from the R/H manifold.

3. Unscrew and remove the end fitting containing the filter/restrictor.

4. Replace or clean components as necessary and re-assemble in reverse order.

5. Refill and pressurise the system (if necessary). (Refer to Commissioning, section 5.1).

Drain tap

Alpha 240/280 - Component Replacement

Differential pressure sensor

Fig. 36

8.38 MAINS WATER INLET VALVE FILTER - Fig. 37

1. Drain the boiler hot water circuit as described in section 8.2.

2. Unscrew the valve end cap fitting and withdraw the filter.

3. Clean or replace and re-assemble in reverse order.

8.39 HEATING RETURN FILTER - Fig. 37

1. Drain the boiler heating circuit as described in section 8.2.

2. Unscrew the heating return valve end cap fitting and withdraw the filter.

3. Clean or replace and re-assemble in reverse order.

Filter

Restrictor

Mains water isolating valve

CH return isolating valve

8.40 DIVERTER VALVE ASSEMBLY - Fig. 38

1. Drain the boiler heating and hot water circuits as described in section 8.2.

2. Remove the two flow switch assemblies from the diverter valve.

3. To avoid damage to the CH temperature sensor on the flow pipe, disconnect its wires (red).

4. Disconnect the following connections from the diverter valve:Two flow sensing pipes, pressure gauge sensor, expansion vessel connection (release the other end to allow the pipe to be moved out of the way), CH flow pipe, small by-pass pipe, CH flow isolating valve.

5. Remove the clips (accessible from under the boiler) retaining the by-pass pipe to the manifold and diverter valve, and withdraw the pipe.

6. Remove the screw securing the diverter valve to the chassis (accessible from under the boiler). Withdraw the valve slightly to disengage it from the manifold, then lift it out of the boiler.

7. Re-assemble in reverse order using the new seals supplied.

8. Refill and pressurise the system. (Refer to Commissioning, section 5.1).

DHW flow

sensing

pipes

Primary flow microswitch assy.

DHW flow microswitch assy.

Fig. 37

CH by-pass

CH expansion vessel connection

DHW temperature sensor

Pressure gauge sensor

Fig. 38

Alpha 240/280 - Component Replacement

8.41 DHW FLOW VALVE - Fig. 39

1. Drain the boiler hot water circuit as described in section 8.2.

2. Remove the flow switch assembly from the front of the diverter valve.

3. Disconnect the two flow sensing pipes from the flow valve.

4. Unscrew (not necessary to remove) the two

DHW flow valve

screws securing the DHW flow valve to the diverter valve (one screw accessible from beneath the boiler) and withdraw the valve.

5. When re-assembling, push the new valve into position, holding it in, while tightening the fixing screws.

6. Re-assemble in reverse order.

8.42 PRIMARY FLOW VALVE DIAPHRAGM - Fig. 40

1. Drain the boiler heating circuit as described in section 8.2.

2. Remove the flow switch assembly from the top of the diverter valve.

3. Disconnect the small pipe from the back of the flow valve.

4. Remove the four screws securing the flow valve and carefully remove it from the diverter valve.

5. Replace the diaphragm and re-assemble in reverse order.

6. Refill and pressurise the system. (Refer to Commissioning, section 5.1).

DHW flow

sensing

pipes

Diaphragm

DHW flow valve securing screws

DHW flow microswitch assy.

Fig. 39

Primary flow microswitch assy.

Small by-pass pipe

8.43 EXPANSION VESSEL

1. Drain the boiler heating circuit as described in section 8.2.

2. Disconnect the pipe from the diverter valve and expansion vessel.

3. Remove the nut and washer securing the expansion vessel to the boiler and lift the vessel out of the boiler.

4. When replacing the vessel, ensure that the connection is towards the front of the boiler and

Fig. 40

re-assemble in reverse order using new seals as necessary.

5. Refill and pressurise the system. (Refer to Commissioning, section 5.1).

Note: If there is less than 350 mm clearance above the boiler or rear exit flue, it is not possible to replace the vessel, in which case an additional vessel should be fitted external to the boiler in the central heating return pipe, as close to the boiler as possible (see Fig. 6).

8.44 DHW EXPANSION DEVICE (if fitted) - Refer to Fig. 35

1. Drain the boiler hot water circuit as described in section 8.2.

2. Unscrew the device from its fitting.

3. Fit the replacement using a new seal.

4. Re-assemble in reverse order.

Alpha 240/280 - Component Replacement

9 WIRING DIAGRAMS

9.1 ILLUSTRATED WIRING DIAGRAM - Alpha 240P and 280P

Alpha 240/280 - Wiring Diagrams

9.2 ILLUSTRATED WIRING DIAGRAM - Alpha 240E and 280E

Alpha 240/280 - Wiring Diagrams

9.3 FUNCTIONAL FLOW WIRING DIAGRAM - Alpha 240P and 280P

Alpha 240/280 - Wiring Diagrams

9.4 FUNCTIONAL FLOW WIRING DIAGRAM - Alpha 240E and 280E

Alpha 240/280 - Wiring Diagrams

10 FAULT FINDING

10.1 CARRY OUT INITIAL FAULT FINDING CHECKS

1. Check that gas, water and electrical supplies are available at the boiler. i.e. Inlet gas pressure = 20 mbar

Electrical supply = 230/240 V ~ 50 Hz CH water system pressurised to between 0.75 and 1.25 bar DHW flow rate is more than 2.5 litre/min

2. Carry out electrical system checks, i.e. Earth Continuity, Resistance to Earth, Short Circuit and Polarity with a suitable meter. Note: These checks must be repeated after any servicing or fault finding.

3. Ensure all external controls are calling for heat and check all external and internal fuses.

Before any servicing or replacement of parts ensure the gas and electrical supplies are isolated.

10.2 LIGHTING PILOT (Alpha 240P and 280P only) - Follow operational sequence

Turn selector to

neon illuminated

YES

Fan runs at slow speed

YES

Depress gas valve control.

Ignition microswitch

operates

YES

Fan runs at max. speed

YES

Air pressure switch proved

neon stays off

YES

After approx. 10 seconds

spark at electrode

YES

Go to section ' ', page 41

Fan connections correct

at fan and main PCB

PCB - M3 connector

Terminals 17, 19 Terminals 16, 17 Terminals 16, 19

Continuity across ignition

microswitch and

Ign.PCB - M1 connector,

between terminals 1, 2

M3 connector, is approx. 440 V across terminals 17, 19

Main PCB - M2 connector, is 240 V across terminals 7, 12

and at Ign. PCB - M2 connector, terminals 3, 4

Ign. PCB - M2 connector,

is 240 V across terminals 3, 6

Ensure connections OK

Volts across

240 V 120 V 120 V

YES

Fan connections correct at main PCB

YES

neon

illuminated

YES

Connections OK

Ign. PCB - is 240 V across

Fa1 connector and N

Go to section ' ', page 41

YES

Ign. PCB - continuity

from TRI to earth ( )

electrode lead

YES

Fan jammed or

winding faulty

Cold resistance

150 ohm 130 ohm

50 ohm

YES

Damaged

Replace main PCB

YES

Replace main PCB

Ensure connections

YES

Replace main PCB

Replace fan

Replace ignition

microswitch assy.

Replace fanFan jammed or faulty wiring

Replace

ignition PCB

Replace

electrode lead

Replace

ignition PCB

Pilot lights

YES

Hold in gas valve control for

approx. 15 - 20 seconds, then

release. Pilot stays alight

YES

Operation sequence successful

Alpha 240/280 - Fault Finding

Gas at pilot

Thermocouple

output = 10 mV min

Continuity across

overheat thermostat

Purge air,

clear blockage

Connections

YES

overheat thermostat

Replace

thermocouple

Replace

10.3 DOMESTIC HOT WATER - Follow operational sequence

Turn selector to

neon illuminated

YES

Turn thermostat to max.

Open DHW tap fully.

DHW flow switch operated

YES

Primary water is diverted from

CH system to DHW heat

exchanger. neon illuminated

YES

Pump runs

YES

Primary flow switch operated

YES

Fan runs at max. speed

YES

Air pressure switch proved

neon stays off

YES (240P/280P)

Spark at ignition electrodes

for upto 10 seconds

YES

(240E/280E)

YES (240E/280E)

Go to section ' ', page 41

Is mains water filter and

differential assy. clean

DHW flow rate more

than 2.5 L/min.

Continuity across DHW

flow microswitch and PCB - M8 connector,

between terminals 35, 36

PCB - M11 connector,

is 20 V DC across

terminals 49, 52

Go to section ' ', page 41

Red reset button

Go to section ' ', page 42

YES

neon

illuminated

neon

illuminated

YES

DHW flow valve

diaphragm damaged

Press white reset

button, if neon

stays illuminated

Go to section ' ', page 41

Press red button to reset

Replace diaphragm

DHW flow valve

rod obstructed

Replace DHW flow

microswitch

Replace neon PCB

Replace main PCB

Go to section ' ', page 42

If still illuminated,

Go to section ' ', page 42

Burner lights

YES

Burner output modulates

to maintain temperature

set at thermostat

YES

Close DHW tap

neon off

YES

DHW flow valve senses no

flow. Primary water diverted

to CH system.

DHW flow switch released (off)

YES

Burner goes out

(240E/280E)

YES

YES (240E/280E)

YES (240P/280P)

Go to section ' ', page 41

But, burner does not stay

alight after 10 seconds

Reduce DHW flow rate

Go to section ' ', page 42

Diverter valve spindle

Fan reduces to slow speed

from 10 to 5 L/min.

Burner modulates

assy. faulty

Fan stops

Go to section ' ', page 42

YES

Pump stops

YES

Operation sequence successful

Alpha 240/280 - Fault Finding

Clean DHW temp.

sensor and DHW

heat exchanger

10.4 CENTRAL HEATING - Follow operational sequence

Turn selector to

neon illuminated

YES

Turn thermostat to max.

neon illuminated

YES

Pump runs

YES

Primary flow switch operated

YES

(240E/280E)

Fan runs at max. speed

YES

Go to section ' ', page 41

240 V across main

terminal block,

terminals 1 and N

External controls

calling for heat

If fitted, internal

clock calling for heat

Go to section ' ', page 41

YES

neon

illuminated

YES

PCB - M11 connector,

is 20 V DC across

terminals 48, 52

YES

Go to section ' ', page 42

YES

Relay energised

and contacts closed

i.e. continuity between

terminals 31, 32 on

PCB - M7 connector

Press white reset button, if neon

stays illuminated

Replace neon PCB

Replace main PCB

Replace relay PCB

Go to section ' ', page 42

Air pressure switch proved

neon stays off

YES (240E/280E)YES (240P/280P)

Spark at ignition electrodes

for upto 10 seconds

YES

Burner lights

YES

(240E/280E)

Burner output modulates until

set temperature is reached

YES

Burner goes out

Red reset button

Go to section ' ', page 42

YES

YES (240E/280E)

YES (240P/280P)

Go to section ' ', page 41

But, burner does not stay

alight after 10 seconds

Go to section ' ', page 42

Fan reduces to slow speed

neon

illuminated

Fan stops

YES

Go to section ' ', page 41

YES

Press red button to reset

Go to section ' ', page 42

Pump continues to run for

5 minutes

YES

Operation sequence successful

If still illuminated,

Go to section ' ', page 42

Alpha 240/280 - Fault Finding

10.5 FAULT FINDING SOLUTION SECTIONS A to L

YES

Pump

If pump jammed, release

Replace main PCB

PCB - M4 connector, terminals 20, 21

Replace pump

240 V at:-

PCB - M11 connector,

is 20 V DC across

terminals 47, 52

Replace main PCB

Replace neon PCB

YES

Main terminals L and N

Check electrical supply

Replace fuse

Replace suppressor

Check wiring

Main terminal fuse

Both sides of suppressor

PCB - M7 connector, terminals 27, 28

neon

illuminated

240 V at:-

YES

CH system pressure 1.0 bar

Re-pressurise system

Vent air, then replace pump

Replace diaphragm

Flow valve rod obstructed

Pump circulating water

Primary flow valve diaphragm damaged

PCB - M3 connector, is 240 V across terminals 13, N

Replace air pressure switch

YES

Check and correct:-

1. Electrical and pressure tube connections

2. Blockage of pressure tubes

3. Restriction in flue

neon

stays off

Replace main PCB

Continuity across primary flow microswitch and PCB - M8 connector, terminals 39, 40

Replace microswitch

YES

DHW/Primary temp. sensor faulty. Cold resistance approx. 11 k ohms (resistance reduces with increase in temp.)

Replace sensor

240E/280E: Fan connections correct at fan and PCB

240P/280P: Fan connections correct at fan and PCB

PCB - M3 connector, is 240 V across terminals 16, 19

PCB - M3 connector, is approx. 440 V across terminals 17, 19

Fan jammed or faulty winding, i.e. cold resistance 45 ohm

Fan jammed or faulty winding

YES

Replace fan

Press red reset button

240V at gas valve and across

ignition PCB - M2 connector, terminals I, H

240V at ignition PCB across

M1 connector, terminal D and

M2 connector, terminal F

YES

Gas at burner

Replace gas valve

Replace reset switch

Replace ignition PCB

YES

Ensure gas is on and purged

Red reset button

illuminated

(240E/280E)

Replace sensor

Replace main PCB

DHW/Primary temp. sensor faulty Cold resistance approx. 11 k ohms (resistance reduces with increase in temp.)

YES

Is 240 V at gas valve and across PCB - M2 connector, terminals 5, 6

Replace gas valve

YES

(240P/280P)

Alpha 240/280 - Fault Finding

Check and correct:-

1. Main PCB - CM1, plug is connected to MET, i.e. Natural Gas

2. Main PCB - CM2, the RLA plug is connected to OFF

3. - Wire connected on PCB - M2 connector between terminal 8 and F3240P/280P only

YES

Burner output

modulates

Modulating coil faulty

cold resistance

YES

Volts at Main PCB - M9 connector

across terminals 41, 42 Max. burner press. approx. 10 V DC Min. burner press. approx. 1.5 V DC

approx. 40 ohm

Replace main PCB

Replace coil

Check and correct:-

1. Ignition electrodes and leads

2. Electrode connections

3. Spark gap and position

Check and correct:-

1. Flame sensing electrode and lead connections

2. Electrode position Flame current should be:Maximum burner pressure - 3.5 mA approx. Minimum burner pressure - 1.5 mA approx.

Overheat thermostat

operated or faulty, i.e. continuity across thermostat terminals

YES

Replace neon PCB

240V at Main PCB - M2 connector,

YES

across terminals 5, 7 and at

Ignition PCB - M1 connector,

across terminals A, C

YES

Allow to cool.

Continuity across

thermostat terminals

more than 1.5 ohm

Replace ignition PCB

YES

Replace main PCB

Air pressure switch proved

neon stays off

YES

Replace ignition PCB

Replace overheat thermostat

neon illuminated,

Go to section ' ', page 41

Continuity across terminals 1 and 3

on reset switch when pressed

(between white wires)

YES

240V at internal clock

terminals 1 and 2

YES

20V DC across clock

terminal 4 and Main PCB - M11

connector, terminal 52

YES

Continuity across

clock terminals 3 and 4

Internal clock calling

for heat

Alpha 240/280 - Fault Finding

Replace ignition PCB

240V at Main PCB - M7 connector,

YES

Wiring between clock

and PCB is correct

Replace clock

Replace reset switch

terminals 27 and 28

Continuity between clock

terminal 4 and Main PCB - M1

connector, terminal 1

YES

Check external controls

YES

Wiring between clock

and PCB is correct

20V DC across Main PCB - M1

YES

connector, terminal 1 and M11

are calling for heat

YES

connector, terminal 52

Replace main PCB

11 SHORT PARTS LIST

Reference

Fig. 3, item 23 Fig. 2, item 23

Fig. 2 or 3, item 22

Fig. 3, item 22

Fig. 2 or 3, item 26

Fig. 3, item 26

Fig. 2 or 3, item 9

Fig. 3, item 9 Fig. 3, item 21 Fig. 2, item 21

Fig. 24 or 25 Fig. 2 or 3, item 15 Fig. 2 or 3, item 15

Fig. 3, item 28 Fig. 2, item 28

Fig. 2 or 3, item 29

Fig. 40 Fig. 39 Fig. 31 Fig. 29 Fig. 29 Fig. 27 Fig. 28 Fig. 33 Fig. 27 Fig. 30 Fig. 14 Fig. 23 Fig. 23 Fig. 27 Fig. 19 Fig. 19 Fig. 19 Fig. 27

Fig. 2 or 3, item 20

Fig. 35

Fig. 33

Fig. 27 or 28

Fig. 32 Fig. 35 Fig.20 Fig. 20 Fig. 20 Fig. 20 Fig. 20 Fig. 28 Fig. 26

Description British Gas GC No.

Burner assembly Burner assembly Main injector 1.18 mm Main injector 1.25 mm Primary heat exchanger and seals Primary heat exchanger and seals DHW heat exchanger and seals DHW heat exchanger and seals Gas valve - Honeywell VK4105A1027 Gas valve - Honeywell V4600A1098 Gas valve modulating coil Pump - Grundfos UPS 15/60 AO and seals Pump head replacement UPS 15/60 and seals Fan assembly - SEL type RL108/4200 A55 Fan assembly - SEL type RL108/4200 Air pressure switch - Honeywell C6065F1100 Primary flow valve and seals DHW flow valve Flow valve microswitch assembly Main PCB Main PCB Neon PCB Neon PCB Temperature sensor Ignition PCB Suppressor - Procond 411.10.5060 Fuse F2A Overheat thermostat - TOD 36TE21 Overheat thermostat - TOD 36TE21 with leads Reset switch - Cometti P12P316 Electrode - Ignition Right Electrode - Ignition Left Electrode - Flame sensing Electrode lead - Ignition Expansion vessel 8 Litre Pressure relief valve 3 bar Insulation panel set (combustion chamber) Automatic air vent and seals Relay PCB Pressure gauge Drain tap Pilot injector 0.27 mm Pilot tube Thermocouple Electrode Electrode lead Ignition PCB Ignition microswitch and cable

Boiler

P 240 280 240 280 240 280

E and P E and P E and P

E and P E and P E and P E and P

E and P

E and P E and P

E and P E and P E and P E and P E and P E and P E and P

Qty.

1 15 15

Alpha Pt. No.

5631970 5632490 5202820 5208040

5632470 5633570A 5625460A 5633110A

5644680

5630520

8440130 5628910A 5610131A

5632530

5631530

5629560 5629960A

5629950

5625770

5631930

5628950

5626680

5626890

8433090

5627350

8450200

8421410

8432560

5626230

8433550

8422570

8422580

8422570

8416730

5625560

5619620

5629970 5625830A

5631550

8922220

5625450

5201550

5207160

5625660

8420930

8417441

5643341

5645050

343 723 343 557 385 830 343 836 343 558 343 837 343 559 343 838

EO2 286

343 716 343 560 343 562 343 563 378 864 378 766 393 947 343 564 343 619 343 568 343 728 343 569 343 730 343 570 343 571 343 729 379 764 343 572 379 798 343 573 378 865 343 724 343 725 343 724 343 727 386 765 397 677 343 577 343 578 343 718 385 839 343 579 392 935 343 574 343 575 343 432

343 576 EO1-724 EO1-725

Alpha 240/280 - Short Parts List

12 SERVICE HISTORY

DETAILS OF BOILER INSTALLATION

Date of Installation: ......................................................................

Name of Installer:.........................................................................

Address: ......................................................................................

....................................................................................................

Postcode: ....................................................................................

Telephone No: .............................................................................

Boiler Serial Number:...................................................................

(see data label on inside of left hand case panel)

DETAILS OF BOILER SERVICE HISTORY

Date of Service Details of Service Service Engineer

................................

.............................................................................................

.......................................

.............................................................................................

These instructions have been carefully prepared but we reserve the right to

Alpha Therm Limited.

Goldsel Road, Swanley, Kent BR8 8EX Tel: (01322) 669443 Fax: (01322) 615017

Part No. 920.334.3

Manual compiled and designed by Publications 2000 - Tel: (01670) 356211 02/00/D120

alpha 240E User guide

Specifications and Main Features

Frequently Asked Questions

User Manual