Baxi Main Combi 24 HE, Installation And Service Instructions Manual

Page 1: ... Baxi Heating UK Ltd 2011 Installation Service Instructions Combi 24 HE These instructions include the Benchmark Commissioning Checklist and should be left with the user for safe keeping ...

Page 2: ...ance Operation 8 4 0 Technical Data 9 5 0 Dimensions and Fixings 10 6 0 System Details 11 7 0 Site Requirements 14 8 0 Flue Options 18 9 0 Plume Displacement 23 10 0 Installation 27 11 0 Commissioning the Boiler 32 12 0 Completion 34 13 0 Servicing the Boiler 35 14 0 Changing Components 37 15 0 Illustrated Wiring Diagram 47 16 0 Fault Finding 48 17 0 Fault Indication Display 52 18 0 Short Parts Li...

Page 3: ...elevant 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 www GasSafeRegister co uk within 10 days If you notify via the Gas Safe Register the register will issue the Building Regulations certificate on members behalf Complete the Benchmark Checklist Instal...

Page 4: ... fully before installing or using the appliance In GB this must be carried out by a competent person as stated in the Gas Safety Installation Use Regulations Definition of competence A person who works for a Gas Safe registered company and holding current certificates in the relevant ACS modules is deemed competent All Gas Safe registered engineers carry an ID card with their licence number and a ...

Page 5: ...s 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 keep your back straight bend your knees Don t twist move your feet avoid bending forwards and sideways and keep the load as close to your body as possible Where possible transport the boiler using a sack ...

Page 6: ...gives details of the model serial number and Gas Council number and is situated on the control box It is visible when the case front panel is removed Fig 1 6 The boiler is intended to be installed in residential commercial light industrial E M C environments on a governed meter supply only 7 The boiler must be installed with one of the purpose designed flues such as the standard horizontal flue ki...

Page 7: ...1 Control PCB 12 Control Box 13 3 Way Valve Assembly 14 Condensate Trap 15 Flame Sensing Electrode 16 Spark Electrode 17 Burner 18 Primary Heat Exchanger 19 Fan Assembly 20 Secondary Heat Exchanger 21 On Off Reset Selector Switch 22 Burner Fault Indicator Neon 23 Power Neon 24 Flame Failure Fault Indicator Neon 25 Central Heating Temperature Control 26 Hot Water Temperature Control 19 18 17 14 15 ...

Page 8: ...ture sensor 4 When the domestic hot water demand ceases the burner will extinguish and the diverter valve will remain in the domestic hot water mode unless there is a demand for central heating IMPORTANT When the selector switch is in the 0 Off position the electrical supply to the boiler is isolated The boiler will not operate and the integral timer if fitted will require resetting once the selec...

Page 9: ...entral Heating only Integral with appliance bar Min Pre charge Pressure 0 5 litre Max Capacity of CH System 125 Primary Water Content 1 0 of Boiler unpressurised Connections copper tails Gas Supply 22mm Central Heating Flow 22mm Central Heating Return 22mm Cold Water Mains Inlet 15mm DHW Flow 15mm Pressure Relief Discharge 15mm Temperatures C H Flow Temp adjustable 35 C to 85 C max 5 C D H W Flow ...

Page 10: ...m D 116mm Ø Min E 185mm F 190mm G 131mm 360 Orientation Tube Ø 100mm D C B A E G F At Least 1 5 Domestic Hot Water Outlet 15mm Cold Water Inlet 15mm Heating Return 22mm Heating Flow 22mm Pressure Relief Valve 15mm Gas Inlet 22mm 65 mm 65 mm 65 mm 65 mm 65 mm Tap Rail 28mm Condensate Drain ...

Page 11: ...ent within the system which can lead to damage of system components All systems must be thoroughly drained and flushed out using for example Sentinel X300 or X400 or Fernox F3 They should be used following the flushing agent manufacturer s instructions System additives corrosion inhibitors and flushing agents descalers should comply to BS7593 requirements e g Sentinel X100 and Fernox MB 1 which sh...

Page 12: ...ion vessel is pre charged to 0 5 bar Therefore the minimum cold fill pressure is 0 5 bar The vessel is suitable for correct operation for system capacities up to 125 litres For greater system capacities an additional expansion vessel must be fitted For GB refer to BS 7074 Pt 1 For IE the current edition of I S 813 Domestic Gas Installations 6 7 Safety Pressure Relief Valve Fig 6 1 The pressure rel...

Page 13: ...of a backflow prevention device and expansion vessel is recommended 4 Also if there is an existing check valve loose jumpered stop cock water meter or water treatment device already fitted to the wholesome water supply connected to the boiler domestic hot water DHW inlet supply then a suitable expansion device may be required 5 The boiler s maximum working mains pressure is 8 bar therefore all pip...

Page 14: ... and the current ETCI rules 4 If the boiler is to be fitted into a building of timber frame construction then reference must be made to the current edition of Institute of Gas Engineers Publication IGE UP 7 Gas Installations in Timber Framed Housing 7 2 Clearances Figs 8 9 1 A flat vertical area is required for the installation of the boiler 2 These dimensions include the necessary clearances arou...

Page 15: ...rear of the gas service cock Fig 10 3 Ensure that the pipework from the meter to the appliance is of adequate size Do not use pipes of a smaller diameter than the boiler gas connection 22mm 7 5 Electrical Supply 1 External wiring must be correctly earthed polarised and in accordance with relevant regulations rules In GB this is the current I E e Wiring Regulations In IE reference should be made to...

Page 16: ...n unheated location the entire condensate discharge pipe should be treated as an external run 9 In all cases discharge pipe must be installed to aid disposal of the condensate To reduce the risk of condensate being trapped as few bends and fittings as possible should be used 10 When discharging condensate into a soil stack or waste pipe the effects of existing plumbing must be considered If soil p...

Page 17: ...ot be less than 300mm in accordance with the diagram below Terminal Position with Minimum Distance Fig 11 mm A1 Directly below an opening air brick opening windows etc 300 B1 Above an opening air brick opening window etc 300 C1 Horizontally to an opening air brick opening window etc 300 D2 Below gutters soil pipes or drain pipes 25 E2 Below eaves 25 F2 Below balconies or car port roof 25 G2 From a...

Page 18: ...gs should be fully engaged The approximate engagement is 40mm Apply soap solution to the seal on each fitting to aid assembly 3 Maximum permissible equivalent flue lengths are Horizontal Concentric 4 metres 4 Any additional in line bends in the flue system must be taken into consideration Their equivalent lengths are Concentric Pipes 135 bend 0 5 metres 93 bend 1 0 metres Twin Flue Pipe 135 bend 0...

Page 19: ... bend or two 135 bends can be included without reduction of the flue length If further elbows are required the flue length must be reduced by the following amounts 1 metre for each 91 5 bend 0 5 metre for each 135 bend 8 2 Twin Vertical Flue Systems 1 Maximum permissible equivalent flue lengths are Vertical Concentric 4m Vertical Twin Pipe 12m Both the air and flue duct can be up to 12 metres long...

Page 20: ...painted 100mmØ 5111080 R Vertical Flue Adaptor 5111070 P Wall Liner 5111067 S Flue Terminal Deflector 5111068 FLUE GROUP N Twin Flue System 80mm diameter E Flue Extension pair 1000mm 5111087 F Flue Bend pair 90 5111072 G Flue Bend 2 pair 135 5111086 J Vertical Flue Boiler Adaptor Kit 5111079 H Vertical Flue Adaptor 5111084 W Pipe Support pair 80mm 5111081 FLUE GROUP A N G Vertical Flue Kits K Vert...

Page 21: ...daptor 1 Undo the screws securing the blanking plate to the boiler top panel Discard the plate 2 There are three restrictor plates supplied in the kit One marked 23 and one marked 27 these can be discarded The third restrictor MUST be positioned as shown in the diagram below 3 Take one of the gaskets supplied in the kit and place on the boiler top panel 4 Align the restrictor as shown Position the...

Page 22: ...the flashing A mastic seal may be necessary From inside the roof adjust the flue to a vertical position and secure to the roof structure with the clamp supplied 8 7 Flue Dimensions 1 The standard horizontal flue kit allows for flue lengths between 100mm and 685mm from elbow to terminal Fig 13 The maximum permissible equivalent flue length is 4 metres NOTE Each additional 45 of flue bend will accou...

Page 23: ...increase with the addition of extensions the length of either or both the 60 100 concentric and 60Ø 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 when measured from the edge of the flue elbow IMPORTANT The maximum equivalent length of concentric flue is 2 5 metres Additional ben...

Page 24: ...stance a concentric length of 2 metres was required and the 60Ø exhaust needed to be 1 5 metres the graph shows that this combination would NOT be permissible as the intersection point would be above the solid diagonal line Example 2 Flue Lengths OK Where both lengths have been determined they can be applied to the graph to check that the installation is permissible For example if it was known tha...

Page 25: ...ure that the concentric assembly and any extensions fall back to the boiler at an angle of 3 and that the external air inlet is to the bottom 8 Use suitable brackets to support the concentric assembly and any extensions and make good inside and outside 9 The 60Ø exhaust can now be fitted Slide the adaptor over the plain end of the 60Ø exhaust Fig 22 and engage the exhaust in the terminal Slide the...

Page 26: ...the extension at 30mm as shown in two positions directly opposite each other Fig 27 20 Using a suitable bit e g 2mm drill through the extension and outlet Secure using two of the screws supplied 21 The remaining screw must be used to secure the adaptor to the concentric terminal 22 When the plume outlet is positioned under a balcony or other projection Fig 28 it must protrude at least 200mm it is ...

Page 27: ...aded area 5 If required mark the position of the gas and water pipes Remove the template 6 Cut the hole for the flue minimum diameter 116mm 7 Drill the wall as previously marked to accept the wall plugs supplied Secure the wall plate using the fixing screws 8 Using a spirit level ensure that the plate is level before finally tightening the screws 9 Connect the gas and water pipes to the valves on ...

Page 28: ... 33 1 Remove the discharge pipe from the kit 2 Determine the routing of the discharge pipe in the vicinity of the boiler Make up as much of the pipework as is practical including the discharge pipe supplied 3 The pipework must be at least 15mm diameter and run continuously downwards to a discharge point outside the building See section 6 7 for further details 4 Utilising one of the sealing washers...

Page 29: ...harge into an outside drain is acceptable 10 7 Fitting The Flue HORIZONTAL FLUE 1 The standard flue is suitable for lengths between 100mm minimum and 685mm maximum as measured from the edge of the flue elbow outlet to the joint between the terminal and air duct Fig 34 2 Locate the flue elbow on the adaptor at the top of the boiler Set the elbow to the required orientation Fig 35 NOTE The flue elbo...

Page 30: ...is will centralise the flue and air ducts and ease assembly Fig 38 8 Insert the flue through the hole in the wall Fit the elbow to the boiler adaptor ensuring that it is pushed fully in 9 Draw the flue back through the wall and engage it in the elbow It may be necessary to use soap solution or similar to ease assembly of the elbow adaptor and flue Fig 39 10 Make good between the wall and air duct ...

Page 31: ...nal control input cables have sufficient slack to allow the control box to drop down Tighten the cable clamp s on the boiler chassis 9 If the optional integral timer is to be used it should be fitted at this point Refer to the instructions supplied with the timer NOTE An external frost thermostat cannot be used with the integral timer 10 9 Preliminary Electrical Checks 1 Prior to commissioning the...

Page 32: ...the screw on the automatic air vent Fig 45 7 The system must be flushed in accordance with BS 7593 see Section 6 2 and the flushing agent manufacturers instructions 8 Pressurise the system to 1 0 bar then close and disconnect the filling loop 9 Turn the gas supply on and purge according to in GB BS 6891 and in IE I S 813 Domestic Gas Installations 10 Test for gas soundness 11 If at any time during...

Page 33: ...t 10l min 8 The pressure should be NG 10 2mbar Propane 21 8mbar If not check that the gas supply pressure is correct Natural Gas 20mbar and Propane 37mbar 9 The pressure can be adjusted if required 10 To check and set minimum pressure first remove one of the modulator wires Adjusting the Pressure Fig 49 11 Remove the plastic protection cap from the pressure adjustment nuts on the valve 12 The smal...

Page 34: ...nd installation These details will be required in the event of any warranty work The publication must be handed to the user for safe keeping and each subsequent regular service visit recorded 4 For IE it is necessary to complete a Declaration of Conformity to indicate compliance with I S 813 An example of this is given in I S 813 Domestic Gas Installations This is in addition to the Benchmark Comm...

Page 35: ... boiler is cool 4 Ensure that both the gas and electrical supplies to the boiler are isolated 5 Slacken the screws securing the facia panel Lift the outercase panel so that its securing tabs are clear of the facia Remove the panel Fig 53 6 Remove the screws securing the inner door panel Lift the panel slightly to disengage it from the studs on top of the case Fig 54 7 Note the positions of the thr...

Page 36: ...lean the combustion box 16 Ensure that the heat exchanger fins are clear of any obstruction NOTE If necessary the secondary heat exchanger may be dismantled see section 14 24 DHW Filters Fig 60 17 If the flow of domestic hot water is diminished it may be necessary to clean the filters 18 Initially check the cold water inlet tap filter 19 Turn the tap off Undo the blanking cap and remove the thread...

Page 37: ...clamp to the left over the pipe 3 Remove the four screws securing the combustion box door and remove the door 4 Ease the front edge of the left hand baffle upwards disengaging the spring clip Disengage the tab on the baffle from the slot in the fan hood 5 Undo the screws securing the fan hood to the appliance back panel and draw the fan and hood assembly forwards 6 Remove the screws and spring was...

Page 38: ... four screws securing the combustion box door and remove the door 2 Undo the screws securing the burner to the injector manifold Draw the burner out of the combustion box pulling the electrode grommets from the slots in the combustion box lower panel 3 Disconnect the electrode leads and grommets from the electrodes Completely remove the burner 4 Undo the screws securing the electrodes to the burne...

Page 39: ...nect the lead and grommet from the electrode being replaced Undo the securing screw and withdraw the electrode to the burner 4 Reassemble in reverse order 14 7 Insulation Fig 67 1 Remove the four screws securing the combustion box door and remove the door 2 Slide the side insulation pieces carefully out of their carriers 3 To replace the rear insulation piece it is necessary to remove the heat exc...

Page 40: ...do the securing screws and remove the pipe and manifold 8 Examine the O ring seals for damage replacing as necessary 9 Fit the inlet pipe and outlet manifold to the new valve ensuring that the O ring seals are in place 10 Reassemble in reverse order and check the burner pressure Section 11 2 14 9 Temperature Sensor Fig 69 1 Ease the retaining tab on the sensor away and disconnect the electrical pl...

Page 41: ...t from the pump body Undo the two screws securing the body to the pipe and manifold and draw the pump forwards 2 Undo the screw on the pump wiring cover and remove the cover Using a suitable flat bladed screw driver press the cable securing levers downwards to release each wire after noting their position 3 Connect the wiring to the new pump Examine the O ring seals on the return pipe and manifold...

Page 42: ... vessel outlet spigot and remove the locknut and spring washer securing the spigot to the boiler chassis 5 Undo the screws and remove the appliance upper cross member Slide the expansion vessel out of the retaining clips 6 Reassemble in reverse order Fully recommission the appliance and system 14 16 Condensate Trap Fig 77 1 Disconnect the two sensing wires from the trap connections 2 Squeeze toget...

Page 43: ... C B and disconnect them 4 Undo the securing screws and remove the P C B Transfer the control knob drive pins to the new P C B and turn them fully anticlockwise 5 Reassemble in reverse order ensuring that the temperature controllers are reset to their previous positions 14 19 Selector Switch Fig 80 1 Note the setting of the selector switch knob and carefully pull it off the facia 2 Completely undo...

Page 44: ...ating pressure differential valve and a domestic hot water pressure differential valve These are connected to a manifold which is joined to the plate heat exchanger DHW Pressure Differential Valve Fig 83 1 Drain the primary circuit 2 Undo the screw securing the microswitch bracket to the valve Fig 82 3 Disconnect the two sensing pipes and slacken the grub screws securing the valve to the diverter ...

Page 45: ... To examine the diaphragm hold the assembly securely and carefully remove the four screws The diaphragm spring will force the two halves of the valve apart 8 Carefully examine the diaphragm and replace it if there is any damage 9 Reassemble in reverse order CH Pressure Microswitch Fig 84 1 Remove the two wires from the Pressure microswitch 2 Undo the screw securing the microswitch bracket to the v...

Page 46: ...wards 6 Remove the secondary heat exchanger from the outer drum by easing it forward 7 Reassemble in reverse order of dismantling 14 24 Flue Overheat Thermostat Fig 88 NOTE The flue overheat thermostat includes a reset button Check that the thermostat will not reset before replacing 1 Remove the fan and hood assembly as described in Section 14 1 2 Pull the two wires off the terminals on the flue o...

Page 47: ... Fan Control PCB Flame Electrode Sensing Microswitch 3 Way Valve M2 M5 M4 M1 M3 FA2 15 16 14 13 12 20 19 18 17 11 10 39 38 37 36 35 9 7 6 5 4 3 2 1 8 Mains Input Fuse Link g y g y b br b b b b br br br br r bk bk br br b r r r r b b b br b 1 bk bk bk b bk bk br 2 3 4 Flue Thermostat Condensate Trap g y g y M7 bk bk 28 29 30 31 32 27 42 43 44 br brown bk black b blue r red y yellow g y green yellow...

Page 48: ...ax speed Burner goes out Turn thermostat to max Pump runs Air pressure switch proved illuminated Burner on neon illuminated Burner output modulates until set temperature is reached Spark at ignition electrodes for up to 10 seconds Go to section A Go to section B Go to section C Go to sections J L D Go to section E Replace PCB Turn selector to the reset position If the light does not extinguish go ...

Page 49: ... flow valve senses no flow Primary water diverted to CH system DHW flow switch released off Close DHW tap Burner goes out Diverter valve spindle assembly faulty Pump stops Operation sequence correct Turn the selector switch to the Reset position and hold for at least 2 seconds If regular resetting is required or appliance still does not operate investigation is necessary Go to section E Burner ext...

Page 50: ...atic air vent is opened Open the automatic air vent 2 NO NO C YES Continuity across flow microswitch and PCB M2 connector terminals 3 4 Replace microswitch 1 NO NO Primary temperature sensor faulty Cold resistance approx 11K ohms resistance reduces with increase in temp Replace sensor 2 YES Fan connections correct at fan PCB M5 connector is 230V across terminals 28 29 Fan jammed or faulty winding ...

Page 51: ...Electrode position Flame current should be 1 μ A approx Replace PCB Replace PCB YES YES Replace flame sensing electrode NO YES Ensure that mains input terminal L is Live 230V and N is Neutral 0V I Check terminal 1 of ON OFF RESET selector is in connection with PCB M1 connector terminal 16 Check electrical continuity across terminals 1 a of ON OFF RESET selector when turned to Reset position Replac...

Page 52: ...s overheated Allow the boiler to cool Turn the selector switch fully anti clockwise against the spring pressure to the Reset position and hold for at least 2 seconds If the boiler does not relight after resetting it is possible that the flue has overheated E The burner has failed to light or incomplete lighting of the burner has occurred Turn the selector switch fully anti clockwise against the sp...

Page 53: ...37 63 E66 411 Spark or Sensing Electrode 247384 72 Pump 248042 101 E66 432 Hydraulic Outlet Assy 248061 102 E66 434 Valve 3 Way Assy 248062 103 343 619 Pressure Differential Assy 248063 131 Temperature Sensor 5108265 135 E66 697 Safety Limit Thermostat 248078 140 Gas Valve 5107339 154 PCB 5112657 169 E66 453 Pressure Gauge 248090 371 Igniter Gas Valve Cable 5112385 333 Flue Overheat Thermostat 511...

Page 54: ...ct the customer s statutory rights If yes and if required by the manufacturer has a water scale reducer been fitted CONDENSING BOILERS ONLY The condensate drain has been installed in accordance with the manufacturer s instructions and or BS5546 BS6798 Yes If the condensate pipe terminates externally has the pipe diameter been increased and weatherproof insulation fitted Yes 54 ...

Page 55: ...er Name Company Name Telephone No Gas Safe Register No Comments Signature Date Engineer Name Company Name Telephone No Gas Safe Register No Comments Signature Date Engineer Name Company Name Telephone No Gas Safe Register No Comments Signature Date Engineer Name Company Name Telephone No Operative ID No Comments Signature Date Engineer Name Company Name Telephone No Gas Safe Register No Comments S...

Page 56: ...ovements 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 Division of Baxi Heating UK Ltd 3879156 Brooks House Coventry Road Warwick CV34 4LL After Sales Service 0844 871 1570 Technical Enquiries 0844 871 1555 Website www mainheating co uk e oe ...