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10

B029

Setting the minimum and the maximum power of the boiler

1. Check that the supply pressure to the gas valve is a minimum of 20 mbar

for natural gas.

2. To do this, remove the screw “A”.

Fit the pipe of the pressure gauge to the pressure connection of the gas
valve “B”.
When you have completed this operation, replace the screw “A” securely
into its housing to seal off the gas.

3. To check the pressure supplied by the gas valve to the burner, remove the

screw “C”. Fit the pipe of the pressure gauge to the pressure outlet of the 
gas valve “D”.
Disconnect the compensation pipe either from the gas valve or from the 
sealed chamber.

4. Set the On/Off button to position <  I  > and the "summer/winter" switch to

the winter position.
To set the maximum power, turn on the hot water tap and allow the hot
water tap to run at a rate of about 8 litres/minute so that the main burner
lights.
Adjust nut “E” on the modureg to set the gas pressure (displayed on the
pressure gauge) corresponding to the maximum power (see table “A” page 11).

5. To set the minimum power, disconnect a supply terminal from the modureg

and adjust screw “F”.
Turn the screw clockwise to increase the pressure and coun-
ter-clockwise to decrease the pressure (displayed on the
pressure gauge) corresponding to 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 the knob of the heating thermostat clockwise to maximum;

8. Remove the left hand inspection panel of the P.C.B. and fit a small

cross-head screwdriver in to the right hand potentiometer. Turn clockwise
to increase the pressure or counter-clockwise to reduce the pressure.
Adjust the setting to the required heating pressure value (displayed on the
pressure gauge), as indicated in the diagrams shown in page 11.

9. Turn off the boiler by placing the main switch to the "Off" position.

Setting pressure for soft ignition.

Disconnect the detection electrode connection from the P.C.B. (see fig.
1.13).
Start the boiler and during the ignition sequence adjust the centre
potentiometer until the gas pressure reads the required gas pressure as
per the table below.
Once the gas pressure is set turn off the boiler and reconnect the
connection to the P.C.B.
NB.: It may be necessary to reset the flame failure reset a number of times
during this operation.

Recommended pressure for 
slow ignition

5 mbar - 1.95 in w.g.

NATURAL GAS (G20)

BUTANE GAS (G30)

PROPANE GAS (G31)

18 mbar - 7.0 in w.g.

19 mbar - 7.4 in w.g.

Setting gas pressures

Summary of Contents for EURO COMBI A/23 MFFI

Page 1: ...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: ...or 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 Cir...

Page 3: ...emoval 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 s...

Page 4: ...ove 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 co...

Page 5: ...e 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 Remov...

Page 6: ...hilips 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...

Page 7: ...g 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...

Page 8: ...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...

Page 9: ...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: ...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 Sett...

Page 11: ...ors 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...

Page 12: ...e 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...

Page 13: ...ator 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...

Page 14: ...d 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...

Page 15: ...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 R...

Page 16: ...s 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...

Page 17: ...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 Re...

Page 18: ...ove 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 cl...

Page 19: ...ectors 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 5...

Page 20: ...d 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...

Page 21: ...n the system 2 Checkthepressureswitch foractivatingpump 3 Check replacewater gaugeandrefill the thesystemproperly 1 Turn theboileroff andthen backon again safetyreset 1 Checkto seeifpumpis stuck 2 Rep...

Page 22: ...lacepower 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...

Page 23: ...ctrode 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 PR...

Page 24: ...erflow rate Checkexchangerfordomestic hot water Primaryexchangerisdefective Low waterpressurein heatingsystem Checkgassettingsandregulation Checkforleaksin heatingcircuit Defectivewatersupplyinlet val...

Page 25: ...itch 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...

Page 26: ...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 Ada...

Page 27: ...27 B029 EX C MI FFI 8 A 23 MFFI A 27 MFFI...

Page 28: ...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 4...

Page 29: ...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...

Page 30: ...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 heade...

Page 31: ...or 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 he...

Page 32: ...ri 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...

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