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15.0 Changing Components

47

© Baxi Heating UK Ltd 2014

The fan and venturi, gas valve, injector pipe,
condensate trap, fan protection sensor, spark and
sensing electrodes can be accessed and changed on
the removal of the airbox door panel.

1. Remove the airbox door panel by loosening the four

1

/

4

turn screws (Fig. 50).

15.5

Spark and Sensing Electrodes 

(Fig. 51)

1. Disconnect all three leads from tabs.

Spark

-

Opaque cable

Earth

-

Green/Yellow cable

Sensing

-

White cable

2. Remove the two screws securing each of the
electrodes to the combustion box door and remove the
electrodes.

3. Fit the new electrodes (and new gasket, as required)
and reassemble in reverse order.

15.6

Fan 

(Fig. 52)

WARNING: The PCB Control and Fan
Assembly are 325 Vdc. Isolate at supply
before access.

1. Loosen the screw holding the injector pipe into the
venturi.

2. Remove the electrical connections to the fan and
protection sensor on the fan.

3. Remove the wing nuts securing the fan to the base of
the combustion box.

4. Lower the fan and remove.

5. If changing the fan remove the screws securing the
venturi and fan protection sensor bracket, noting the
positions of the injector opening and sensor bracket, fix
them to the new fan.

6. Fit the new fan and reassemble in reverse order.

The injector pipe, condensate trap and gas valve can
be changed after the removal of 
the fan.

Wing Nuts

Injector Pipe

Screw

Electrical Connections

Electrical Connection

Protection 

Sensor

Injector

Opening

Gasket

Venturi

Fan

Air Box Door Panel

Sensing

Earth

Spark

Combustion 

Box Door

Fig. 50

Fig. 51

Fig. 52

Summary of Contents for 12 HE A

Page 1: ...Baxi Heating UK Ltd 2014 Installation Service Instructions HE A Range These instructions include the Benchmark Commissioning Checklist and should be left with the user for safe keeping...

Page 2: ...lable from the Heating and Hotwater Industry Council who manage and promote the Scheme Visit www centralheating co uk for more information Building Regulations and the Benchmark Commissioning Checklis...

Page 3: ...levant LABC You must ensure that the certificate number issued by the Gas Safe Register is written onto the Benchmark Checklist Scheme Members only Call Gas Safe Register on 0800 408 5577 or log onto...

Page 4: ...ith the normal operation of the appliance without express written permission from the manufacturer or his agent could invalidate the appliance warranty In GB this could also infringe the Gas Safety In...

Page 5: ...ute is clear and unobstructed If possible avoid steps wet or slippery surfaces unlit areas etc and take special care on ladders into lofts Technique When handling or lifting always use safe techniques...

Page 6: ...0 System Details 12 7 0 Site Requirements 16 8 0 Flue Options 21 9 0 Plume Displacement 26 10 0 Installation 30 11 0 Electrical 36 12 0 Commissioning the Boiler 38 13 0 Fitting the Outer Case 41 14 0...

Page 7: ...e installed with one of the purpose designed flues such as the standard horizontal flue kit part no 236921 1 2 Important Information Man made mineral fibre Some component parts of this appliance insul...

Page 8: ...Protection Thermostat 7 Fan Assembly 8 Condensate Trap 9 PCB Housing Assembly 10 Gas Tap 11 Gas Air Ratio Valve 12 Flow Pipe Connection 13 Return Pipe Connection 14 Flow Temperature Safety Thermostat...

Page 9: ...nd thereby the gas rate to achieve optimum operation If the flow temperature is greater than the set point or the TRVs all shut down then fan post purge occurs 6 Fan Post Purge The pump and fan are on...

Page 10: ...m Min 0 10 20 30 40 20 40 60 80 100 120 140 160 180 200 220 Water Flow Rate litres min Pressure Drop mbar 8 17 25 33 42 50 58 66 75 83 91 Pressure Drop in wg Hydraulic Resistance Chart Appliance Type...

Page 11: ...ove the top of the flue elbow should be 27 5mm to incorporate the 1 5 fall in the flue from the terminal to the elbow The 1 5 fall provided by the elbow is to allow condensate to run back to the boile...

Page 12: ...ems will be subject to corrosion unless they are flushed and an appropriate water treatment is applied To prevent this follow the guidelines given in BS 7593 Treatment of Water in Domestic Hot Water C...

Page 13: ...C drop across the boiler b The pump must be fitted on the flow c The pump must be fitted in accordance with the pump manufacturer s instructions d The open vent pipe must be taken up from a tee in a h...

Page 14: ...N CH on HW on HW off L N E L N P F E b g y w o gr 1 C 2 g y S Plan Valve Cylinder Stat Room Stat Boiler Pump Timer 230V 50Hz L N E L N CH on HW on L N E L N P F E Motor S Plan Valve Motor o o gr b g...

Page 15: ...provided a Listed double check valve or some other no less effective backflow prevention device is permanently connected at the inlet to the circuit and the temporary connection is removed after use T...

Page 16: ...e to the relevant requirements In GB this is the current I E E Wiring Regulations and Building Regulations In IE reference should be made to the current edition of I S 813 Domestic Gas Installations a...

Page 17: ...e is of adequate size to ensure correct operation Do not use pipes of a smaller diameter than the boiler gas connection 7 5 Electrical Supply 1 External wiring must be correctly earthed polarised and...

Page 18: ...with material suitable for external use 9 If the boiler is fitted in an unheated location the entire condensate discharge pipe should be treated as an external run and sized and insulated accordingly...

Page 19: ...e Heating Element is NOT a substitute for correct installation of the condensate drain ALL requirements in this section must still be adhered to Boiler vi pumped into an external soil vent pipe 2 5 Mi...

Page 20: ...t The terminal position must ensure the safe and nuisance free dispersal of combustion products Fig 17 Fig 17a 300 min Terminal Assembly TopView Rear Flue Property Boundary Line NOTE The distance from...

Page 21: ...bend 1 0 m NOTE Flue length is measured from point X to Y as shown IMPORTANT All flue systems must be securely supported at least once every metre Suitable pipe supports are available as accessories...

Page 22: ...al equivalent length for this example is 17 2 34 4 51 6 metres 1m extension 135 bend 91 5 bend 1m 1 3m 4 8m 5 2 2 5 0m 2 6m 9 6m AIR DUCT No of fittings pipes Sub total Equivalent Length Value Equival...

Page 23: ...0mm 243014BAX T Vertical Flue Boiler Adaptor 5106888 S Flue Terminal Deflector 248167 FLUE GROUP P Twin Flue System 80mm diameter E Flue Extension 1000mm 246137 500mm 246136 250mm 246135 F Flue Bend p...

Page 24: ...e 2 Fix the vertical adaptor and gasket to the top panel with the previously removed screws 8 5 For Twin Flue Systems 1 Undo the screws securing the blanking plate to the boiler top panel Discard the...

Page 25: ...d secure to the roof structure with the clamp supplied IMPORTANT If the boiler is not fitted immediately after the flue system temporary precautions must be taken to prevent rain entry into the room o...

Page 26: ...h the 70 110 concentric and 70 exhaust 5 Standard concentric flue extension kits may be added between the boiler elbow and the terminal assembly 6 The minimum length of the concentric flue is 100mm wh...

Page 27: ...l bends Example 1 Not Permissible If for instance a concentric length of 3 25 metres was required and the 70 exhaust needed to be 10 metres the graph shows that this combination would NOT be permissib...

Page 28: ...o support the concentric assembly and any extensions and make good inside and outside Secure the flue trim to the wall 9 The 70 exhaust can now be fitted to the spigot at the terminal end 10 If it is...

Page 29: ...in an enclosed box but the air inlet and plume outlet MUST remain in free air 17 It is also possible to separate the plume outlet from the 93 elbow to allow the flue to be installed as shown in Fig H...

Page 30: ...see table Fig 20 for wall thicknesses and flue diameters 6 Drill and plug the wall as previously marked Secure the wall plate Fig 22 7 Ensuring the wall plate is level both horizontally and vertically...

Page 31: ...Preparing The Boiler 1 Remove the outer carton and packaging 2 Lift the outercase upwards and remove 3 Remove the internal packaging Fig 22a Break Off Upper Lower Pipe Run Options Internal Polystyrene...

Page 32: ...connection is the return 2 It is essential that the flow and return pipes are connected to the boiler correctly The flow connection incorporates the boiler thermostats and a flow switch 3 The boiler c...

Page 33: ...ckness 181 3 Take the flue and mark off X from the terminal end as indicated in the diagram Fig 27 Check your dimensions The flue tubes are fixed together Cut through both tubes whilst resting the flu...

Page 34: ...nection on top of the boiler Secure with the four screws supplied in the kit 11 Make good between the wall and air duct outside the building ensuring the 1 5 drop between the terminal and elbow 12 The...

Page 35: ...ing screw and hinge down the PCB housing b Remove the Red jumper labelled CN12 from the bottom left hand side of the PCB c Hinge back up the PCB housing and secure with screw 4 Route the incoming elec...

Page 36: ...en g y Green Yellow op Opaque y Yellow Gas Valve g op Spark Electrode g y bk bk bk bk r w w Flame Detection Electrode Condensate Trap Flow Overheat Thermostat Fan Overheat Thermostat g y r b r r Flow...

Page 37: ...op Opaque y Yellow 11 2 Illustrated Wiring Diagram GasValve Fan CondensateTrap CH Flow Switch Flow Thermistor Spark Electrode Flame Detection Electrode Main PCB N L r r gy gy r b br g w Flow Overheat...

Page 38: ...boiler case Detail of system treatment should be added for future reference 6 Turn the gas supply on and purge according to in GB BS 6891 and in IE I S 813 Domestic Gas Installations 7 Remove the top...

Page 39: ...s supply in accordance with the GSIUR Note Check record the CO combustion ratio at both maximum a low rate before calling 0844 871 1555 Yes No No Yes Yes No Is CO 350ppm and CO CO2 ratio 0 004 No Yes...

Page 40: ...the property working Measure the Gas Rate 4 With any other appliances pilot lights turned OFF the gas rate can be measured It should be as shown in Section 4 0 Technical Data 5 Carefully read and comp...

Page 41: ...plete a Declaration of Conformity to indicate compliance to I S 813 An example of this is given in I S 813 Domestic Gas Installations This is in addition to the Benchmark Commissioning Checklist 6 Ins...

Page 42: ...for Installation Maintenance of Gas Fired Boilers not exceeding 70kW advises that The person carrying out a combustion measurement should have been assessed as competent in the use of a flue gas anal...

Page 43: ...the Outercase Section 13 0 WARNING The PCB Control and Fan Assembly are 325 Vdc Isolate at supply before access 7 Release the four 1 4 turn screws securing the air box door panel and remove the door F...

Page 44: ...ion box base and withdraw the base j Lower the central insulation panel and check condition Fig 44 Replace the lower insulation pad if necessary k Ensure the heat exchanger fins are clear of any obstr...

Page 45: ...before access 3 Isolate the water circuit and drain the system as necessary A drain point is located on the heat exchanger manifold at the right hand side of the boiler Fig 45 to enable the heat excha...

Page 46: ...6 2 and 12 1 Flow Switch Clip Flow Pipe Fig 47 Support Bracket 15 4 PCB Figs 48 49 WARNING The PCB Control and Fan Assembly are 325 Vdc Isolate at supply before access 1 Remove the plastic button cove...

Page 47: ...WARNING The PCB Control and Fan Assembly are 325 Vdc Isolate at supply before access 1 Loosen the screw holding the injector pipe into the venturi 2 Remove the electrical connections to the fan and pr...

Page 48: ...and gasket to the new valve 10 Fit the new gas valve and reassemble in reverse order NOTE Check for gas tightness after replacing gas valve 11 Check the CO CO2 ratio and CO2 level at the flue samplin...

Page 49: ...t the new burner and reassemble in reverse order 15 11 Heat Exchanger 1 Drain the boiler see section 15 1 paragraph 2 3 2 Remove all components in the base of the airbox 3 Undo the screws on the suppo...

Page 50: ...nger and remove the lower insulation pad 6 Fit the new insulation pad and reassemble in reverse order 15 13 Heat Exchanger Upper Insulation Pad Fig 60 1 Remove all components in the base of the airbox...

Page 51: ...58 Flow Temperature Thermistor Red 240670 B E06 059 Flow Switch 242459 C E06 060 Safety Thermostat Black 242235 D PCB 5129147 E Fan 5109925 F Gas Valve 241900 G E06 085 Viewing Window 242484 H Condens...

Page 52: ...s replace LV wiring harness PCB Fault Replace PCB PCB Fault Replace PCB PCB Fault Replace PCB YES YES YES YES YES YES YES YES YES YES YES YES Go to Electrical Supply section of the fault finding instr...

Page 53: ...ystems Controls and System Wiring 240V at B Check wiring from terminal block to PCB Check for shorts on pump fan gas valve Replace if shorted replace fuse YES NO Replace PCB YES YES NO NO ELECTRICAL S...

Page 54: ...ff on After 5 sec is there 240V at E Pump or Pump Wiring fault Is there a blockage in the system NO YES YES E Optional Pump Live N L F N L Turn mains off unplug 7 way connector to PCB Is there continu...

Page 55: ...as necessary YES YES NO NO YES Remove Gas Valve check inlet filter for blockage Otherwise incorrect gas supply to boiler Is there at least 18mbar dynamic at gas valve inlet Lead from PCB to Gas Valve...

Page 56: ...bustion chamber door seal trim seal NO YES NO YES Reconnect stat Disconnect fan stat When fan temp 60 C is there continuity across stat Reconnect stat Disconnect the larger of the 6 way PCB connectors...

Page 57: ...Wire Entry end S W Fan Connection PCB Connection Fan Connection PCB Connection NOTE The fan is supplied with 325 Vdc Fan Fault Finding should only be carried out after the boiler has been electricall...

Page 58: ...ired Thermostatic radiator valves Fitted Not required Automatic bypass to system Fitted Not required Boiler interlock Provided ALL SYSTEMS s instructions Yes What system cleaner was used What inhibito...

Page 59: ...mpany name Telephone No Gas safe register No Record At max rate CO ppm AND CO At min rate Where Possible CO ppm AND CO Comments Signature SERVICE 06 Date Engineer name Company name Telephone No Gas sa...

Page 60: ...s in our products which may affect the accuracy of the information contained in this leaflet All goods are sold subject to our standard Conditions of Sale which are available on request MAIN A Trading...

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