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Supplied By www.heating spares.co  Tel. 0161 620 6677

A/23 MFFI - A/27 MFFI

G.C.N. 47-116-10 / 47-116-12
Servicing Instructions
Type C Boilers

LEAVE THESE  INSTRUCTIONS
ADJACENT TO THE  GAS  METER

Summary of Contents for EuroCombi Type C A23 MFFI

Page 1: ...Supplied By www heating spares co Tel 0161 620 6677 A 23 MFFI A 27 MFFI G C N 47 116 10 47 116 12 Servicing Instructions Type C Boilers LEAVE THESE INSTRUCTIONS ADJACENT TO THE GAS METER ...

Page 2: ... 9 Removing the Spark Ignitor 11 Removing the Gas Valve 12 1 5 Access to the Hydraulic Circuit Removing the D H W Secondary Exchanger 12 Removing the Safety Valve 13 Removing the Automatic Air Vent 13 Removing the Main Flow Circuit Switch 13 Removing the Pump 14 Removing the Pressure Gauge 14 Removing the Expansion Vessel 15 Removing the Overheat Thermostat 15 Removing the Heating Temperature Sens...

Page 3: ...his will also require the removal of the casing To dismantle the front part of the casing proceed as follows 1 Remove screw A see fig 1 1 2 Lift the front panel up and forward see fig 1 2 A Fig 1 2 Fig 1 1 To ensure efficient safe operation it is recommended that the boiler is serviced annually by a competent person Before starting any servicing work ensure both the gas and electrical supplies to ...

Page 4: ...o lower control panel 1 Remove the screws B 2 Push the two side panels outward slightly fig 1 5 3 Rotate the control panel forward and down Fig 1 4 B Fig 1 5 B C Fig 1 7 Fig 1 6 C To access the areas where the adjustment and control devices are located simply remove the plugs by pressing from the inside unscrew the screws C and remove the bottom part of the instrument panel rotating it upwards Fig...

Page 5: ...burner see fig 1 12 4 Remove the injectors using a No 7 socket spanner 5 Replace in reverse order Removing the burner and the injectors 5 B029 Removing the sealed chamber frontal cover 1 3 Access to the Combustion Chamber Remove the screws D Remove the screws E Removing the combustion cover E E E E E E E Fig 1 8 Fig 1 9 D D D D Fig 1 10 Fig 1 11 Fig 1 12 F push push ...

Page 6: ... 5 Remove screw H using a Philips No 2 star tip screwdriver see fig 1 16 6 Slide the electrode gently downward see fig 1 17 To replace repeat the steps in reverse order paying particular attention to the following a Centre the electrode in the positioning hole carefully otherwise the electrode may break b Check that the cables have been connected correctly c Check that the rubber gasket covers the...

Page 7: ...f the sealed chamber see fig 1 21 Use a No 2 star tip screwdriver to remove the switch from the plate Fig 1 21 Fig 1 20 7 B029 1 Drain the boiler of water 2 Release the two connection nuts I connecting the exchanger to the flow and return pipes see fig 1 18 3 Pull it straight out see fig 1 19 Removing the main heat exchanger Removing the air pressure switch Fig 1 18 I Fig 1 19 L L K J J ...

Page 8: ...nturi see fig 1 23 Removing the venturi device 1 Disconnect electrical connections and remove screws O using a No 2 star tipped screwdriver see fig 1 24 2 Pull fan to the right forward and remove see fig 1 25 3 Remove fan from mounting plate 4 Remove screws P see fig 1 26 Removing the fan M N Fig 1 22 Fig 1 23 Fig 1 24 Fig 1 25 Fig 1 26 O O P P ...

Page 9: ...Supplied By www heating spares co Tel 0161 620 6677 9 B029 1 4 Servicing and Removal of the Gas Valve 1 2 3 4 A B C E F D SIT TANDEM SIT SIGMA 1 2 3 4 A B C E F D ...

Page 10: ...the minimum power see table A page 11 6 When you have completed the above operations turn off the hot water tap re connect the supply terminal to the modureg on the gas valve and replace the cap on the screw of the modureg Setting the maximum heating circuit power 7 To set the maximum heating circuit power place the On Off button to position I and the summer winter switch to winter position Turn t...

Page 11: ...rner pressure Burner injectors min 13 x 1 25 Gas rate max 3 0 m 106 0 ft Gas rate min 1 2 m 3 h 3 h 42 3 ft 3 h 3 h Inlet pressure 20 mbar 7 8 in w g Burner pressure max 12 3 mbar 4 8 in w g 2 0 mbar 0 8 in w g 13 x 0 72 0 88 m 31 1 ft 0 35 m 3 h 3 h 12 3 ft 3 h 3 h 28 mbar 10 9 in w g 28 mbar 10 9 in w g 5 1 mbar 2 0 in w g 13 x 0 72 1 15 m3 h 40 6 ft3 h 0 46 m3 h 16 2 ft3 h 37 mbar 14 4 in w g 3...

Page 12: ...ntrol and is situated on the P C B see the electrical diagrams By adjusting the potentiometer it is possible to change the time interval between the burner shutting down and its next ignition It is preset at 1 minute and can be adjusted from 0 to 2 minutes Use this control in particular situations where continuous shutting down and ignition of the main burner occurs 40 50 60 70 80 C C Anti cycling...

Page 13: ...29 Removing the spark generator SIT Tandem gas valve 1 Disconnect ignition leads Q1 by pulling upwards see fig 1 30 2 Remove the screws R1 see fig 1 31 with a Pozidrive No 2 star tip screwdriver 3 Remove the spark generator Fig 1 30 Fig 1 31 Fig 1 32 Q1 R1 R1 ...

Page 14: ...that the O rings are in good condition and replace if necessary Important Before any component is removed the boiler must be drained of all water Removing the gas valve 1 Disconnect all the cables from the solenoid and modureg 2 Remove the spark generator 3 Release the top nut S using a 30 mm open ended spanner see fig 1 31 4 Remove the screws T from the bottom of the gas valve pipe see fig 1 32 A...

Page 15: ...V see fig 1 38 2 Remove the valve Removing the automatic air vent 1 Unscrew valve W see fig 1 39 Removing the main circuit flow switch 1 Remove the cable of the main circuit flow switch Y 2 Remove the screws Y1 see fig 1 40 3 Remove the main circuit flow switch Fig 1 38 Fig 1 39 Fig 1 40 V W Y Y1 Y1 ...

Page 16: ... fig 1 41 2 Release the nuts A1 and remove the pump see fig 1 42 Removing the pressure gauge 1 Remove the inspection panel see fig 1 6 1 7 2 Release coupling A2 using a 14 mm open ended spanner see fig 1 43 3 Push the pressure gauge through the control panel from the rear see fig 1 44 A1 A1 Z A2 Fig 1 41 Fig 1 42 Fig 1 43 Fig 1 44 ...

Page 17: ...g the overheat thermostat 1 Remove the electrical connection from the overheat thermostat see fig 1 48 2 Then remove the thermostat from the pipe by releasing its securing clip Removing the heating temperature sensor N T C 1 Remove the electrical connector by pulling off the thermostat connections and unscrewing the sensor probe with a 14 mm open ended spanner see fig 1 49 A3 A4 Fig 1 45 Fig 1 46 ...

Page 18: ...panel see fig 1 6 1 7 2 Remove fuse see fig 1 50 1 6 Access to the Control System Removing the time clock 1 Remove the inspection panel see fig 1 6 1 7 2 Remove electrical connection of the clock A5 see fig 1 51 3 Unclip the clock from the panel and remove see fig 1 52 Fig 1 50 Fig 1 51 Fig 1 52 A5 ...

Page 19: ...ve the electrical plug connectors and screws A8 see fig 1 55 8 To remove the 240V P C B remove the electrical plug connectors and screws A9 see fig 1 56 9 Replace either P C B in reverse order Fig 1 53 Fig 1 54 Fig 1 55 Fig 1 56 A6 A6 A6 A6 A7 A7 A8 A8 A9 A9 N B It is possible to by pass the time clock in the event of failure by simply unplugging the electrical connection from the P C B see fig 1 ...

Page 20: ...kthepower supplycord plugand outlet 3 Check replacethepower supplyPCB Pressthe On Off Button FOR BOILERS EQUIPPED WITHAN ELECTRONIC ANT FREEZE SYSTEM HAS THE SAFETY BEEN TRIGGERED TO ACTIVATE THE DEVICE T sensor 5 C FOR BOILERS EQUIPPED WITHAN ELECTRONIC ANT FREEZE SYSTEM HAS THE SAFETY BEEN TRIGGERED TO ACTIVATE THE DEVICE T sensor 5 C DO THE PROGRAMMING TIMER AND OR EXTERNAL THERMOSTAT NEED TO B...

Page 21: ...within 40sec 1 Checkforairin the system 2 Checkthepressureswitch foractivatingpump 3 Check replacewater gaugeandrefill the thesystemproperly 1 Turn theboileroff andthen backon again safetyreset 1 Checkto seeifpumpis stuck 2 Replacecirculation pump 1 Check wiring 2 Check replace wiretoPCB 3 Replace powersupply PCB 4 Replacecontrol PCB 5 Checkmicro switch when hot waterisrequested A B ...

Page 22: ...replacePCB wire 4 Check replacepower supplyPCB 5 Check replacecontrol PCB 1 pressureswitch wiring 2 Checkwhetherreset button isstuck 3 detection electrode Check replaceair Check replaceflame 1 2 3 Check replacepower supplyPCB 4 5 Check replacewiring Check replacePCB wire Check replacecontrol PCB Check replaceair pressureswitch 1 Replacefan 1 Reset theboiler PUMP SAFETY DEVICE ACTIVATED INTERNAL SA...

Page 23: ...t bytheflame 2 Check theelectrode 3 Check thepower PCB 4 Check thecontrol PCB 1 Checksupplyofgasto gas valve 2 CheckpowersupplyPCB 3 Checkcontrol PCB 4 Checkfunctionalityofthe valve Shutdown LEDoff Restartofthefan IS THE AIR PRESSURE SWITCHACTIVATED ARE THE FUMES DISCHARGED CORRECTLY SAFETY SHUTDOWNOFTHE BOILER ACTIVATED 1 Checkfluedischarge 2 Checkventuri small pipes 3 Checkwireforairpress switch...

Page 24: ...tingsandregulation Checkwaterflow rate Checkexchangerfordomestic hot water Primaryexchangerisdefective Low waterpressurein heatingsystem Checkgassettingsandregulation Checkforleaksin heatingcircuit Defectivewatersupplyinlet valve Secondaryexchangerisdefective Expansion vessal isempty Detection electrodesaredefective Checkgassettingsandregulation Checkelectrical circuit forflamedetection Faulty con...

Page 25: ...Faulty main circuit flow switch Faulty flame detection Faulty overheat thermostat Faulty exhaust fumes sensor Faulty heating sensor N T C Faulty D H W sensor N T C A b C d E F G I m 1 2 3 4 5 6 2 2 Fault Finding Using the Total Check System Pump fed Main flow switch closed Air pressure switch N O Flame detected Water at required temperature Room thermostat clock no demand or selector in summer set...

Page 26: ...ng Temperature Adjustment P Time Clock Connection Q On Off L E D R On Off Switch S Interface Wire for P C B s T Relay Motorised Valve U Ignitor Relay V Gas Valve Relay W Fan Relay X Circulation Pump Relay Y Selector TCS2 Aa Adaptor British Gas use only A01 Air Pressure Switch A02 Fan A03 Gas Valve A04 Ignitor A05 Motorised Valve A06 Circulation Pump A07 Flame Detector A08 Earth Terminal A09 Flame ...

Page 27: ...Supplied By www heating spares co Tel 0161 620 6677 27 B029 EX C MI FFI 8 A 23 MFFI A 27 MFFI ...

Page 28: ...07 109 82 66 64 67 66 69 70 64 71 75 75 63 65 75 126 72 121 74 10 62 73 80 28 46 45 45 116 54 114 49 50 51 115 113 48 49 52 52 53 47 45 34 33 32 35 29 30 103 27 117 5 96 102 100 101 100 41 39 97 108 14 37 39 34 38 29 41 40 43 44 42 301 4 302 301 4 4 4 93 92 92 91 94 95 23 83 106 105 79 36 31 76 77 78 99 104 110 321 361 363 364 362 371 372 373 374 375 311 A 23 27 MFFI 102 16 22 17 4 SHORT SPARE PAR...

Page 29: ...be C H W Microswitch for 3 way main flow group Gasket 1 2 Manual vent cock Safety valve 3 bar 1 2 Pressure gauge Time clock P C B EX C MI FFI P C B EI A MFFI P C B cable Fan Fan Fan inlet gasket Venturi exhaust manifold header Air pressure switch Air pressure switch Fastening spring Automatic air release valve Gasket 1 O ring Secondary exchanger plate type exchanger 23kW Secondary exchanger plate ...

Page 30: ...robe C H W Microswitch for 3 way main flow group Gasket 1 2 Manual vent cock Safety valve 3 bar 1 2 Pressure gauge Time clock P C B EX C MI FFI P C B EI A MFFI P C B cable Fan Fan Fan inlet gasket Venturi exhaust manifold header Air pressure switch Air pressure switch Fastening spring Automatic air release valve Gasket 1 O ring Secondary exchanger plate type exchanger 23kW Secondary exchanger plat...

Page 31: ...p probe C H W Microswitch for 3 way main flow group Gasket 1 2 Manual vent cock Safety valve 3 bar 1 2 Pressure gauge Time clock P C B EX C MI FFI P C B EI A MFFI P C B cable Fan Fan Fan inlet gasket Venturi exhaust manifold header Air pressure switch Air pressure switch Fastening spring Automatic air release valve Gasket 1 O ring Secondary exchanger plate type exchanger 23kW Secondary exchanger p...

Page 32: ...acturer Merloni TermoSanitari SpA Italy Commercial subsidiary MTS GB LIMITED MTS Building Hughenden Avenue High Wycombe Bucks HP13 5FT Telephone 01494 755600 Fax 01494 459775 Technical Service Hotline 01494 539579 23 99 84 1268 000 B029 Stampa BIEFFE Recanati ...

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