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27

8.23 DIVERTER VALVE ASSEMBLY - Fig. 26

1.

Drain the boiler heating circuit as described in section 8.2.

2.

Remove the diverter valve motor as described in section
8.14.

3.

Remove the two 4 mm allen screws and pull the plastic
housing from the manifold.

4.

Fit the new valve assembly in reverse order using new
seals.

5.

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

8.24 HEATING RETURN FILTER - Refer to Fig. 13

1.

Drain the boiler heating circuit as described in section 8.2.

2.

Disconnect the by-pass valve unions and remove the
valve. Withdraw the filter from the return.

3.

Clean or replace and re-assemble in reverse order.

8.25 HEATING PRESSURE RELIEF VALVE - Refer to Fig. 2

1.

Drain the boiler heating circuit as described in section 8.2.

2.

Disconnect the relief valve outlet fitting. Undo the screw securing the relief valve and pull out the valve.

3.

Re-assemble in reverse order using a new 'O' ring seal.

4.

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

8.26 HEATING EXPANSION VESSEL - Refer to Fig. 2

1.

Drain the boiler heating circuit as described in section 8.2.

2.

Disconnect the pipe from the expansion vessel and remove the re-usable support strap (see Fig. 19) by inserting a small
screwdriver into the clip on the strap.

3.

Remove the nut and washers securing the vessel to the hot water storage cylinder and lift the vessel out of the boiler.

4.

Re-assemble in reverse order using a new seal.

5.

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

8.27 DHW EXPANSION VESSEL - Refer to Fig. 12

1.

Close the mains water supply valve and ensure that all hot water taps are closed. Release the pressure from the hot water circuit.

2.

Disconnect the expansion vessel union and remove the re-usable support strap (see Fig. 19) by inserting a small
screwdriver into the clip on the strap.

3.

Remove the expansion vessel.

4.

Re-assemble in reverse order. Refill and pressurise the hot water circuit by opening the mains water supply valve.

8.28 PRIMARY PRESSURE SWITCH - Refer to Fig. 25

1.

Drain the boiler heating circuit as described in section 8.2.

2.

Disconnect the wiring from the pressure switch.

3.

Remove the switch by unscrewing it from the manifold.

4.

Re-assemble in reverse order using the new washer supplied.

5.

Refill and pressurise the system.

8.29 DHW TEMPERATURE/PRESSURE RELIEF VALVE - Refer to Fig. 2

1.

Partially drain the hot water circuit, so that the water in the hot water storage cylinder is below the relief valve connection, as
described in section 8.2.

2.

Remove the valve from the storage cylinder.

3.

Re-assemble in reverse order.

4.

Refill the storage cylinder by opening the mains water supply valve and opening a hot water tap.

Fig. 26

Alpha CB50 - Component Replacement

Diverter valve
manifold

4 mm Allen screws

Diverter valve motor

Cover
screws

Diverter valve
housing

Motor securing
screws

Summary of Contents for Alpha CB50 Boiler

Page 1: ...ion Boiler with Unvented Hot Water Storage From Boiler Serial No 27B32500001 Nepicar House London Road Wrotham Heath Sevenoaks Kent TN15 7RS For Technical help or for Service call ALPHA HELPLINE Tel 0870 3001964 British Gas G C No 47 532 18 For use with Natural Gas only Leave these instructions with the User ...

Page 2: ... personnel in accordance with the following recommendations Gas Safety Installation and Use Regulations 1984 as amended All current Building Regulations issued by the Department of the Environment i e Approved Document L1 Building Standards Scotland Consolidation Regulations issued by the Scottish Development Department Local Water Bye Laws Health Safety Document No 635 The Electricity At Work Reg...

Page 3: ...ion Vessel Size pre charge press Flow Connection Return Connection Relief Valve Connection Recommended System Pressure cold 2 5 bar 0 5 bar 82 C 3 bar 44 PSI 8 L at 0 8 bar 22 mm 22 mm 15 mm 1 0 bar 2 2 SYSTEM Burner 15 blade Main Heat exchanger DHW Storage Cylinder Main Burner Injectors Flue Outer Duct Flue Inner Duct Stainless steel Copper Stainless Steel 1 3 mm 15 off Epoxy coated Aluminium 2 3...

Page 4: ...0 000 60 000 50 000 40 000 35 495 metres 1 0 2 2 3 6 4 2 4 8 5 0 feet 3 28 7 22 11 8 13 7 15 7 16 4 Output Available pump head metres 2 1 3 4 4 2 4 6 5 1 5 3 feet 6 9 11 1 13 7 15 1 16 7 17 3 metres 3 5 2 6 1 6 1 2 0 9 0 8 feet 11 5 8 5 5 2 3 9 2 9 2 6 metres 2 7 1 8 1 2 1 0 0 7 0 6 feet 8 9 5 9 3 9 3 3 2 3 2 0 Pressure loss across boiler gal min 4 8 4 0 3 27 2 73 2 18 1 94 litre min 18 4 15 2 12 ...

Page 5: ...ief Valve 14 Automatic Air Vent 15 Main Burner 16 Main Heat Exchanger 17 Fan 18 Air pressure Switch 19 Room Sealed Chamber 20 CH Expansion Vessel 21 Storage Cylinder 22 DHW Temperature Pressure Relief Valve 23 DHW Storage Temperature Sensor 24 Secondary Heat Exchanger 25 DHW Expansion Vessel 26 Check Valve 27 Pressure Reducing Valve with Filter 28 Tundish 29 Ignition Electrodes 30 Flame Sensing El...

Page 6: ...he boiler must be designed and constructed specifically for the purpose i e comply with the Building Regulations 3 4 FLUE SYSTEM Fig 3 The flue system must be installed in accordance with BS 5440 1 The flue assembly supplied for the boiler is 0 75 m in length For horizontal flues ensure there is a slight downward slope towards the terminal Additional flue components are available as follows 0 75 m...

Page 7: ...nformation HORIZONTAL FLUE OPTIONS Lmax 4 metres For L H side flue X 140 for R H side flue X 380 VERTICAL FLUE OPTIONS Hmax 4 metres L B E F X mm 90 bend 1 metre L B C X mm 2 x 45 bends 1 metre L B C E X mm L B C X mm E C B B C C B E B F ...

Page 8: ...ousing reference DM2 The boiler may be installed in any room or internal space although particular attention is drawn to the requirements of the current IEE Wiring BS7671 Regulations and in Scotland the electrical provisions of the Building Regulations applicable in Scotland with respect to the installation of the boiler in a room or internal space containing a bath or shower Where a room sealed b...

Page 9: ...nd pre charged to a pressure of 0 5 bar By pass The boiler incorporates a by pass However where all radiators are fitted with thermostatic radiator valves it is recommended that a system by pass preferably automatic is fitted Alpha cb50 General Boiler Information Fig 5 3 8 FILLING THE CENTRAL HEATING SYSTEM Figs 6 7 The system design pressure cold should be set to 1 0 bar This pressure is equivale...

Page 10: ...ce 3 10 UNVENTED HOT WATER STORAGE SYSTEM The installation is subject to Building Regulations approval and the Local Authority must be notified of the intention to install The CB50 boiler is supplied with all the components required for an unvented hot water system i e temperature pressure and expansion relief valves expansion vessel check valve and tundish All these components are factory fitted ...

Page 11: ...res and there is a distance of 3 m from any plastic guttering systems that would collect such discharge Note The discharge will consist of scalding water and steam Asphalt roofing felt and non metallic rainwater goods may be damaged by such discharges HIGH LEVEL TERMINATION D1 D2 300 mm minimum Tundish Type A air gap End of pipe to be clearly visible Worked example The example below is for a G tem...

Page 12: ...on 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 If rear exit flue is used mark the position of the hole for the flue 3 Side exit flue Continue the horizontal centre line of the flue across the wall to the side wall then along thesidewall235mm ensurethelinesarehorizontal This will give the position of the ...

Page 13: ...ed This pipework must be installed as recommended in Unvented Hot Water Storage System section 3 10 6 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 4 6 FIT THE FLUE Figs 13 14 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...

Page 14: ...s at the bottom 13 Pull the outer duct towards the bend Check that the flue terminal protrudes 130 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 if applicable 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...

Page 15: ...ply cable ensure the cable clamp that has been fitted is removed and connect as follows Removethetwoscrewssecuringtheterminalblockcover from the back of the control box see Fig 15 Pass the mains supply cable through the cable clamp and connect asfollows BrowntoL BluetoNandGreen Yellowto Ensure correct polarity Note Ensure that the length of the earth wire is such that if the supply cable is pulled...

Page 16: ...e 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 Red wires to terminals 3 and 4 or as per the instructions supplied with the clock Ensure wiring is correct 5 Replace the clock cover Do not overtighten the fixing screws 6 Leave the control panel open until commissioning procedures have...

Page 17: ...ifying 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 2 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 12 Thoroughly flus...

Page 18: ... thermostat to maximum 2 The burner will light at the factory pre set maximum output 3 Set the selector switch to 0 to turn off the boiler Disconnect the pressure gauge and tighten the test point screw Test for gas soundness using suitable leak detection fluid Note Refer to Technical Data section 2 1 for burner pressure settings 5 6 FINAL COMMISSIONING 1 Allow the heating system to heat up then ba...

Page 19: ...NTRAL HEATING MODE If there is a call for central heating the diverter valve is operated the pump will start to circulate the primary heating water 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 heating water in the boiler approaches that set by the adjustab...

Page 20: ...ts and check the tightness of any fittings that may be leaking 5 It is recommended that the operation of the heating pressure relief valve is checked 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 6 Refill vent and re pressurise the system as necessary Refer to Commissioni...

Page 21: ...E BOILER 1 Replace the burner ensuring it is located correctly into the rear locating hole the flame sensing lead grommet is fitted correctly and the ignition electrodes are connected Connect the main burner s union nut and tighten Reconnect the flame sensing lead plug 2 Replace the combustion chamber front cover take care not to damage the insulation panels Replace the flue hood cover and reconne...

Page 22: ...ll the bottom forwards and remove Remove the two fixing screws one each side securing the control panel and hinge it forward 1 Heating circuit refer to Fig 12 Close the central heating flow and return valves and drain the heating circuit via the drain point G in Fig 12 2 Hot water circuit refer to Fig 12 Close the mains water supply valve and drain the hot water storage cylinder via the store drai...

Page 23: ...y out of the flue bend and withdraw the assembly horizontally from the front of the chamber Disconnect the wiring from the fan when it becomes accessible 5 Remove the two screws securing the fan to the mounting plate 6 Fit the new fan to the mounting plate and re assemble in reverse order Note Connect the fan wiring Blue and Brown wires to the terminals on the motor polarity not important and the ...

Page 24: ...lder 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 8 13 MAIN PCB Fig 24 1 Gain access to the control panel as described in section 8 1 2 Disconnect all the wiring connectors from the PCB 3 Remove the five fixing screws and carefully withdra...

Page 25: ... pressure sensing tube 5 Remove the four screws securing the flue hood and lift out the flue hood 6 Remove the heat exchanger by pulling it towards the front withdrawing the right side pipe through the room sealed chamber side panel being careful not to damage the combustion chamber insulation Remove the pipe from the heat exchanger and fit it to the new one 7 Fit the new heat exchanger using new ...

Page 26: ... room sealed chamber and remove the pipe 3 Unscrew the automatic air vent from the pump outlet Fit a new one using a new O ring 4 Re assemble in reverse order 5 Refill and pressurise the system Refer to Commissioning section 5 1 8 22 PUMP Fig 25 Drain the boiler heating circuit as described in section 8 2 Pump Head 1 Remove the four socket head screws securing the pump head to the body Withdraw th...

Page 27: ... to the hot water storage cylinder and lift the vessel out of the boiler 4 Re assemble in reverse order using a new seal 5 Refill and pressurise the system Refer to Commissioning section 5 1 8 27 DHW EXPANSION VESSEL Refer to Fig 12 1 Closethemainswatersupplyvalveandensurethatallhotwatertapsareclosed Releasethepressurefromthehotwatercircuit 2 Disconnect the expansion vessel union and remove the re...

Page 28: ...closed Releasethepressurefromthehotwatercircuit 2 Unscrew the cartridge from the valve body 3 Clean or replace the filter cartridge and re assemble in reverse order 4 Refill and pressurise the hot water circuit by opening the mains water supply valve 8 32 CHECK VALVE Refer to Fig 12 1 Closethemainswatersupplyvalveandensurethatallhotwatertapsareclosed Releasethepressurefromthehotwatercircuit 2 Disc...

Page 29: ...29 9 WIRING DIAGRAMS 9 1 ILLUSTRATED WIRING DIAGRAM Alpha CB50 Wiring Diagrams ...

Page 30: ...30 9 2 FUNCTIONAL FLOW WIRING DIAGRAM Alpha CB50 Wiring Diagrams ...

Page 31: ... 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 4 Check that the gas and water pipework has been connected to the correct connections on the boiler and all valves are open However before any serv...

Page 32: ...32 Alpha CB50 Fault Finding 10 3 DOMESTIC HOT WATER Follow operational sequence ...

Page 33: ...33 Alpha CB50 Fault Finding 10 4 FAULT FINDING SOLUTIONS A to F ...

Page 34: ...34 Alpha CB50 Fault Finding 10 5 FAULT FINDING SOLUTION SECTIONS G to L ...

Page 35: ...ylinder and seals Gas valve Honeywell VK4105M Pump Diverter valve motor assembly Fan assembly Air pressure switch Primary pressure switch Diverter valve DHW expansion vessel 4 litre Temperature pressure relief valve 90 C 7 bar Pressure reducing valve 2 5 bar Expansion relief valve 6 bar Main PCB Diverter valve PCB Temperature sensor Automatic flow regulator valve Fuse F2A Overheat thermostat Check...

Page 36: ...Service Service Engineer 04 05 D146 Part No 1 019706 Manual compiled and designed by Publications 2000 Tel 01670 356211 These instructions have been carefully prepared but we reserve the right to alter the specification at any time in the interest of product improvement Alpha Therm Limited 2005 Alpha Therm Limited NepicarHouse LondonRoad WrothamHeath Sevenoaks Kent TN15 7RS Tel 0870 3001964 email ...

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