Baxi Maxflow Combi WM, Installation And Servicing Instructions

Page 1: ...on Boiler with Unvented Hot Water Storage Installation and Servicing Instructions Please leave these instructions with the user IMPORTANT This boiler MUST be installed with the Unvented Kit Part No 247369 which is in a separate box supplied with the boiler ...

Page 2: ...to buy Everyone who works at Baxi has a commitment to quality because we know that satisfied customers mean continued success We hope you get a satisfactory service from Baxi If not please let us know Baxi Maxflow Combi WM G C No 47 075 03 Baxi is a BS EN ISO 9001 Accredited Company The boiler meets the requirements of Statutory Instrument The Boiler Efficiency Regulations 1993 No 3083 and is deem...

Page 3: ...7 5 0 Dimensions and Fixings 8 6 0 System Details 9 7 0 Site Requirements 13 8 0 Installation 18 9 0 Commissioning the Boiler 24 10 0 Servicing the Boiler 26 11 0 Changing Components 28 12 0 Illustrated Wiring Diagram 37 13 0 Fault Finding 38 14 0 Short Parts List 42 Section Page Contents ...

Page 4: ...d outercase panel Fig 2 8 The boiler is intended to be installed in residential commercial light industrial E M C environments on a governed meter supply only 9 The boiler must be installed with one of the purpose designed flues such as the standard horizontal flue kit 10 All systems must be thoroughly flushed and treated with inhibitor see section 6 2 1 2 Installation 1 The appliance is suitable ...

Page 5: ... Vessel 16 Air Pressure Switch 17 Cylinder Safety Valve 18 Hot Water Storage Cylinder 19 Central Heating Temperature Control 20 Domestic Hot Water Temperature Control 21 ON OFF Selector Switch 22 Indicator Neons 23 Reset Button 24 Flame Failure Reset Button 25 Pressure Gauge 2 2 Optional Extras 1 Various flue extensions bends vertical flue kits control accessories etc are available as optional ext...

Page 6: ...the temperature set by the adjustable domestic hot water control knob When this temperature is reached the burner extinguishes and the fan stops The pump continues to run for 3 minutes to prevent residual heat build up in the boiler When the hot water demand has been satisfied the 3 way diverter valve operates to divert the primary heating water to the central heating if the selector is set to and...

Page 7: ...nput gross Max Min C H DHW kW 31 1 11 9 Btu h 106 130 40 610 Heat Output Max Min kW 28 0 10 4 Btu h 95 555 35 492 Electrical Supply 230V 50Hz Power Consumption 190W External Fuse Rating 3A Internal Fuse Rating F2A External Controls 230V switching Electrical Protection IP44 IPx4D Appliance must be connected to an earthed supply Appliance Category CAT II 2H 3 Gas Rate Natural Gas Max Min After 10 Mi...

Page 8: ...107mm Ø Min E 180mm F 160mm G 120mm H 160mm 360 Orientation in Steps of 45 Tube Ø 100mm D C B A E G F H Hot Water Outlet 15mm Outer Case Cold Mains Inlet 15mm Heating Return 22mm Heating Flow 22mm Safety Valve 15mm Gas Inlet 22mm 62mm 55mm 55mm 100mm 100mm 118mm 110mm ...

Page 9: ...For optimum performance after installation this boiler and its associated central heating system must be flushed in accordance with the guidelines given in BS 7593 Treatment of water in domestic hot water central heating systems This must involve the use of a proprietary cleanser such as BetzDearborn Sentinel X300 or X400 or Fernox Superfloc Full instructions are supplied with the products but for...

Page 10: ...rnal by pass For example a 15mm pipe between the flow and return controlled by a valve or an uncontrolled radiator 6 4 System Control 1 The boiler is designed for use in a heating system that incorporates external controls i e a minimum of a timer device 2 Suitable timer kits are available as optional extras 3 For optimum operating conditions and maximum economy the fitting of a programmable therm...

Page 11: ...e the cold fill pressure is 0 8 bar The vessel is suitable for correct operation for system capacities up to 125 litres 27 5gal For greater system capacities an additional expansion vessel must be fitted refer to BS 7074 Pt 1 6 7 Pressure Relief Valve Fig 8 1 The pressure relief valve is set at 3 bar therefore all pipework fittings etc should be suitable for pressures in excess of 3 bar 2 The pres...

Page 12: ...ions fittings etc should be suitable for pressures in excess of 8 bar The pressure reducing valve supplied in the Unvented Kit must be fitted The manufacturer of any outlet fittings such as a shower valve may require a lower maximum pressure The pressure reduction must take account of all fittings connected to the DHW system 6 9 Showers 1 If a shower control is supplied from the appliance it shoul...

Page 13: ...Limited could invalidate the appliance warranty and infringe the Gas Safety Installation and Use Regulations 7 3 Clearances Fig 11 12 1 A flat vertical area is required for the installation of the boiler 2 The clearances around the outer case are for the flue elbow pipework etc The clearance in front of the appliance is for servicing purposes when installed in a cupboard or compartment 3 Additiona...

Page 14: ...e any air vents in the room in which it is installed If it is installed in a cupboard or compartment permanent air vents are required at high and low levels see Table 1 The vents must communicate with the same room or be direct to outside on the same wall 2 When installed in a cupboard or compartment a 75mm clearance for air movement must be left in front of the boiler when any door or panel is cl...

Page 15: ... gutter drain soil pipe 150 C Below eaves 200 D Below a balcony car port roof 200 E From vertical drain pipes and soil pipes 150 F From internal or external corners 300 G Above adjacent ground or balcony level 300 H From a surface facing a terminal 600 I Facing a terminal 1200 J From opening door window in carport into dwelling 1200 K Vertically from a terminal on the same wall 1500 L Horizontally...

Page 16: ...om the adhesive seal Apply the seal to the rear of the trim flange Fig 18 3 Locate the trim over the flue terminal and push it back to the wall to compress the seal Fig 19 7 11 Terminal Guard Fig 20 1 When codes of practice dictate the use of terminal guards they can be obtained from most Plumbers and Builders Merchants 2 There must be a clearance of at least 50mm between any part of the terminal ...

Page 17: ... is of the same type as the optional concentric 90 bend Bends can be used to route the flue pipe around obstacles within the dwelling and to enable the flue terminal to be positioned according to requirements By combining two 45 bends and a straight piece a wide 90 bend can be achieved As it is possible to rotate the bends through 360 various S bends can be produced 5 The illustrations opposite sh...

Page 18: ... fixing holes 7 Using the screws and washers provided secure the mounting bracket to the wall 8 Lift the boiler and locate the slots in the upper chassis over the hooks on the mounting bracket Fig 22 THIS OPERATION WILL REQUIRE ASSISTANCE 9 Remove the sealing plugs from the gas and water connections 10 Connect the gas and water valves together with the appropriate copper tail ensuring that the sea...

Page 19: ...ons approval and the Local Authority must be informed of the intent to install Consideration must be given to Building Regulations document G3 1 The components supplied in the box marked Unvented Kit MUST be fitted to the mains water supply 2 No isolating valves must be fitted between these components and the boiler 3 The combined filter and pressure reducing valve must ideally be fitted before th...

Page 20: ...ms are installed where discharges from safety devices may not be apparent i e in dwellings occupied by blind infirm or disabled people consideration should be given to the installation of an electronically operated device to warn when discharge takes place Note The discharge will consist of scalding water and steam Asphalt roofing felt and non metallic rainwater goods may be damaged by such discha...

Page 21: ...lue elbow on the adaptor at the top of the boiler Set the elbow to the required orientation rear right or left 4 Measure the distance from the outside wall face to the elbow Figs 25 26 This dimension will be known as X 5 Taking the air duct mark dimension X as shown Fig 27 Measure the length of waste material and transfer the dimension to the flue duct Fig 27 6 Remove the waste from both ducts Ens...

Page 22: ...mp and tighten the screws Fig 30 13 Draw the air duct out of the wall and align it with the elbow Position the seal so that it equally covers the joint Fig 31 14 Remove the screws from the second clip provided Prise the clip apart and fit it over the seal Refit the screws to the clip and tighten them Fig 31 15 Where possible position the clips so that the screws are not visible 16 Make good betwee...

Page 23: ... If the room thermostat being used incorporates an anticipator it MUST be wired as shown in Fig 32a IMPORTANT The external control MUST be suitable for 230V switching 8 Ensure that both mains input and where fitted external 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 ...

Page 24: ...g for heat 2 Set the hot water temperature control to maximum and the selector switch to the OFF position Fig 36 Draw off all hot water to ensure that the store is cold 3 Slacken the pressure test point sealing screw Fig 38 and connect a pressure gauge Disconnect the sensing pipe from the spigot adjacent to the pressure test point 4 Turn the selector switch to the Domestic Hot Water position and p...

Page 25: ...or safe keeping and each subsequent regular service visit recorded 2 Instruct the user in the operation of the boiler controls Hand over the User s Operating Installation and Servicing Instructions and the Log Book giving advice on the necessity of regular servicing 3 Show the user the position of the tundish and discharge pipe 4 Remove the plastic coating from the appliance outercase panels 5 Hin...

Page 26: ...panel Fig 45 8 Disconnect the gas supply from the burner inlet manifold and remove the electrode lead from the Spark electrode Fig 46 9 Draw the burner forwards out of the combustion box and disconnect the flame sensing lead Take care not to damage or lose the sealing washer on the gas inlet flange Fig 46 10 Note the positions of the two sensing tubes and three wires on the pressure switch and rem...

Page 27: ...ced with pressure the cartridge should be cleaned Cleaning The Cartridge 20 Turn off the mains water supply Unscrew the cartridge from the the valve body and rinse thoroughly in clean water Fig 48 21 Check the primary system pressure vessel charge and system pressure and the d h w pressure vessel charge Repressurise as necessary 22 Turn the heads of the temperature pressure relief valve the d h w ...

Page 28: ...hood forward edge 5 Draw the fan and hood assembly forwards out of the combustion box 6 Undo the two screws securing the fan to the fan hood and remove the fan by disengaging the tabs from the slots in the hood 7 Undo the two screws securing the outlet adaptor to the fan Transfer the adaptor to the new fan 8 Fit the new fan to the hood and reassemble in reverse order 11 3 Burner Fig 52 1 Undo the ...

Page 29: ...om the combustion box lower panel 7 Carefully manoeuvre the gas valve and outlet pipe from the appliance taking care not to damage the O ring seal in the gas inlet pipe manifold If necessary remove the gas inlet pipe from the pipe bracket 8 Undo the four screws securing the gas outlet pipe manifold to the valve Remove the outlet pipe taking care not to damage the O ring seal in the outlet pipe man...

Page 30: ...ssembly as described in Changing Components Section 11 2 paragraphs 1 to 5 2 Carefully draw the side insulation pieces out taking care not to damage them Ease the heat exchanger sideways while extracting each piece 3 Undo the two retaining screws on the heat exchanger rear flanges Pull the heat exchanger forwards disengaging the flow and return spigots from the pipe fittings 4 Reassemble in revers...

Page 31: ...ce disengage it from the retaining tabs on the lower edge of the inner door 2 Fit the new insulation piece by carefully locating it behind the tabs and pushing back Completion Carefully clean away any insulation from the combustion box and reassemble in reverse order 11 8 Temperature Sensors Figs 62 63 1 The temperature sensors on the store and flow pipe are of the same type and the replacement pr...

Page 32: ... shafts will align with the slots and carefully fit the new board 4 Reconnect all plugs and connectors previously removed and reassemble in reverse order Relay PCB 1 Disconnect the plug from the PCB and undo the screw securing the PCB to the control panel 2 Reassemble in reverse order Ignition PCB 1 Note the position of each plug and connector including the earth wire and remove them 2 Undo the PC...

Page 33: ...assemble in reverse order 11 13 Pressure Reducing Valve Cartridge Fig 70 1 Turn off the mains water supply 2 Unscrew the cartridge from the the valve body and discard 3 Reassemble in reverse order 11 14 Expansion Relief Valve Cartridge Fig 71 1 Turn off the mains water supply and drain down the domestic hot water storage tank 2 Unscrew the cartridge from the the valve body and discard 3 Reassemble...

Page 34: ...ter storage feed pipe nut at the adaptor on the base of the tank Remove the pipe by easing it out of the valve body taking care not to damage the O ring seal or washer 5 Disconnect the valve from the remaining pipes taking care not to damage the O ring seals Remove the screws from the body and engage them in the new component 6 Reassemble in reverse order 11 17 Differential Pressure Switch Fig 76 ...

Page 35: ...ature Pressure Relief Valve Fig 79 1 It is necessary to remove the expansion vessel as described in 11 18 prior to changing the relief valve 2 Undo the nut on the discharge pipe at the valve and ease the pipe out of its retaining clip on the case side 3 Undo the nut on the temperature and pressure relief valve securing it to the spigot on the storage tank and remove the valve 4 Ensure that the sea...

Page 36: ...he union nuts on the inlet and outlet connections and draw the pump forwards 2 Undo the screw on the pump wiring cover and remove the cover Using a suitable flat bladed screwdriver press the cable securing levers downwards to release each wire after noting their position 3 Connect the wiring to the new head and set the pump speed to 3 Using new sealing washers fit the new pump fit the air vent to ...

Page 37: ...erter Valve Pump Overheat Thermostat Gas Valve Air Pressure Switch Fan Primary Sensor H W Storage Sensor Main PCB Neon PCB Relay PCB Ignition PCB Flame Sensing Electrode br b bk bk r r b b bk bk r g bk bk bk w b br r g bk w b br r g g r b bk br b br br b br b bk b br b br br b b w w w w br brown bk black b blue r red y yellow g green g y green yellow w white Mains Input Link b g y g y b br br Rese...

Page 38: ...Turn thermostat to max Is neon illuminated Air flow monitor neon stays off Red reset button 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 Replace neon PCB Go to section B Go to section C Go to section J Go to section D Go to section E Go to section H Press to reset Go to section F Go...

Page 39: ...ermostat After storage temperature is reached neon off Spark at ignition electrodes for up to 10 seconds Go to section A Go to section B Go to section C Go to section J Go to section D Go to section E Go to section H Press to reset Go to section F Go to section I Go to section G Burner goes out Fan stops Pump stops Operation sequence correct Safety Thermostat neon illuminated Press white reset but...

Page 40: ... primary flow microswitch and main PCB M7 connector terminals 24 25 Replace microswitch 1 NO NO DHW primary temp sensor faulty cold resistance approx 11K ohms resistance reduces with increase in temp Replace sensor 2 YES Fan connections correct at fan and ignition PCB Ignition PCB M2 connector is 230V across terminals 17 18 Fan jammed or faulty winding Replace ignition PCB Replace fan YES 3 D Igni...

Page 41: ...er pressure 230V at Main PCB M4 connector across terminals 9 10 and at ignition PCB M3 connector across terminals 8 9 YES Replace ignition PCB Replace ignition PCB YES Main PCB M1 connector is 20V DC across terminals 49 50 YES Replace ignition PCB YES YES YES NO H Verify in the mains input terminal block L is Live 230V and N is Neutral 0V I Check terminal 1 on reset button is in connection with ig...

Page 42: ...47391 140 E59 897 Gas Valve 247392 102 E59 890 Diverter Valve 3 Port Valve 247395 169 385 839 Pressure Gauge 247396 92 E59 886 Safety Valve 3bar 247402 274 E59 948 Cartridge Pressure Reducing Valve 247403 275 E60 000 Cartridge Expansion Relief Valve 247404 79 E59 881 Storage Temp Pressure Relief Valve 247405 32 E59 868 Heat Exchanger 247428 35 E59 869 Expansion Vessel 247431 44 E03 569 Burner Inje...

Page 43: ...gnition 247385 284 343 828 Electrode Lead Sensing 247765 290 E60 098 Microswitch Loom 247453 135 E59 895 Limit Thermostat O Heat 247393 131 343 571 Temperature Sensor 247394 172 379 764 Suppresor 247397 154 E59 910 Main PCB 247389 155 E59 911 Ignition PCB 247399 156 E59 912 Neon PCB 247400 171 343 718 Relay PCB 247401 155 171 59 284 131 290 64 172 154 156 135 ...

Page 44: ...Baxi UK Limited Brownedge Road Bamber Bridge Preston Lancashire PR5 6SN www baxi com After Sales Service 08706 096 096 Technical Enquiries 08706 049 049 Comp No 247308 Iss 7 10 01 921 970 1 ...