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GARDA HE M96.24SM/B Service Manual

Manual is about: Wall hung, fan flue, room sealed, high efficiency

Summary of M96.24SM/B

  • Page 1

    Wall hung, fan flue, room sealed, high efficiency gas boiler service manual garda he models: g.C. Appl. No. M96.24sm/b 47---970---25 m96.28sm/b 47---970---26 garda he silver models: g.C. Appl. No. M96.24sm/d 47---970---27 m96.28sm/d 47---970---28 leave this manual adjacent to the gas meter.

  • Page 2

    Table of contents 1 overall information 1 . . . . . . . . . . . . . . . . . . 1.1 overall view 1 . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 hydraulic diagram 1 . . . . . . . . . . . . . . . . . . . . 2 general access and emptying hydraulic circuits 2 . . . . . . . . . . . . . . . . . . . ...

  • Page 3

    1 1 overall information 1.1 overall view fan safety thermostat main heat exchanger burner ignition electrodes gas valve control panel combustion chamber automatic air release pump d.H.W. Temp. Probe d.H.W. Heat exchanger expansion vessel detection electrode valve condensing diverter valve air pressu...

  • Page 4

    2 2 general access and emptying hydraulic circuits 2.1 nomenclature 2 6 1 5 4 3 fig. 1 1 right side panel 2 front panel 3 control panel lid 4 control panel cover 5 service panel 6 left side panel 2.2 body panels warning: isolate the boiler from the mains electricity supply before removing any coveri...

  • Page 5

    General access and emptying hydraulic circuits 3 fig. 4 5 remove the screws e and remove the service panel (fig. 5); 6 to gain access to the electronic regulation pcb and the full sequence ignition device remove the screws f and remove the control panel lid (fig. 5); e f f fig. 5 2.4 access to the s...

  • Page 6

    4 3 diagrams 3.1 wiring diagram ignition electrodes flame detection electrode bn = brown bu = blue bk = black wh = white rd = red gy = grey safety thermostat external controls electric supply fan air pressure switch time switch 1 2 3 t bk bk t bk bk bk m ~ m ~ bk bk bk bk m ~ bk bk bk terminal block...

  • Page 7

    Diagrams 5 bn = brown bu = blue bk = black wh = white rd = red gy = grey gn = green ye = yellow vt = violet og = orange gnye = green/yellow ignition electrodes flame detection electrode external controls electric supply fan air pressure switch time switch 1 2 3 t bk bk t bk bk bk m ~ m ~ bk bk bk bk...

  • Page 8

    Diagrams 6 3.2 functional flow diagrams ptc j1--- 1 l general layout transformer n electronic control p.C.B. (low voltage section) j1--- 2 j3--- 3 j3--- 5 j3--- 4 j3--- 2 j3--- 1 j2--- 4 j2--- 5 three way diverter valve pump full sequence ignition device fuse 1,6a t ptc j1--- 1 l transformer active ...

  • Page 9

    Diagrams 7 3.3 circuit voltages 230~ s up pl y ne tw or k 230~ 230~ 0 electrical voltages with burner on during c.H. Or d.H.W. Operation only during c.H. Operation only during d.H.W. Operation 230~ 230~ 230~ 0 pump full sequence ignition device 3 w ay di ve rte rv al ve 0 0 electronic control p.C.B....

  • Page 10

    Diagrams 8 230~ s up pl y ne tw or k 230~ 230~ 0 electrical voltages with burner on during c.H. Or d.H.W. Operation only during c.H. Operation only during d.H.W. Operation 230~ 230~ 230~ 0 pump full sequence ignition device 3 w ay di ve rte rv al ve 0 0 electronic control p.C.B. 230~ 230~ modulating...

  • Page 11

    9 4 fa ul tf in di ng c om po ne nt s to ch ec k s ec tio n of th e m an ua l! (n ot e re f. In br ac ke ts ) --- (1 ) --- (2 ) --- (3 ) 22 .1 --- (4 ) 7 8. 2 9. 2 10 .8 11 .2 12 .4 13 .2 15 .5 16 .2 17 18 .2 19 .2 20 .2 21 .1 --- (7 ) --- (8 ) --- --- loc k--- out sig nal lam pre d d ef ec t # pow ...

  • Page 12

    10 c om po ne nt s to ch ec k s ec tio n of th e m an ua l! (n ot e re f. In br ac ke ts ) --- --- --- (8 ) --- (7 ) 21 .1 20 .2 19 .2 18 .2 17 16 .2 15 .5 13 .2 12 .4 11 .2 10 .8 9. 2 8. 2 7 --- (4 ) 22 .1 --- (3 ) --- (2 ) --- (1 ) loc k--- out sig nal lam pre d pre ssu re gau ge saf ety val ve ex...

  • Page 13

    11 5 primary heat exchanger 5.1 function the primary heat exchanger a in fig. 9 has the function of transferring heat produced from combustion of the gas to the water circulating in it. A fig. 9 the hydraulic circuit is composed of 8 elliptical pipes connected in parallel (fig. 10). Fig. 10 5.2 remo...

  • Page 14

    12 6 condensing heat exchanger 6.1 function the return water flows through the condensing heat ex- changer a in fig. 12 and fig. 13. By reducing the combustion products temperature, the latent heat of the vapour is transferred to the water cir- cuit, allowing an extra gain of useful heat. The conden...

  • Page 15

    13 7 d.H.W. Heat exchanger 7.1 function the d.H.W heat exchanger a in fig. 14 and fig. 16 al- lows the instantaneous transfer of heat from the primary hydraulic circuit to the water destined for d.H.W use. A fig. 14 the schematic structure is shown in fig. 15. Primary hydraulic circuit domestic hot ...

  • Page 16

    14 8 pump 8.1 function the pump a in fig. 18 and fig. 19 has the function of making the water in the main circuit circulate through the main heat exchanger, the condensing heat ex- changer and therefore through the c.H. System (during the c.H. Function) or through the secondary heat ex- changer (dur...

  • Page 17

    15 9 three way diverter valve 9.1 function the diverter valve a (fig. 21) has the function of modify- ing the hydraulic circuit of the boiler by means of an electric command given by the electronic control p.C.B. In order to send the water that exits the primary heat ex- changer towards the c.H. Sys...

  • Page 18

    Three way diverter valve 16 c d e fig. 24 9.4 removal of the diverter group and its internal parts 1 remove the front and both side case panels. 2 empty the primary circuit and the d.H.W circuit of the boiler. 3 remove the electric actuator (see section 9.3). 4 remove the fixing spring f (fig. 25) a...

  • Page 19

    17 10 electronic control p.C.B. 10.1 function from other boiler devices.... C.H. Temperature probe ntc d.H.W. Temperature probe ntc d.H.W. Flow switch primary circuit flow switch room thermostat (if fitted) time switch flame presence signal* *from the full sequence ignition device on the electronic ...

  • Page 20

    Electronic control p.C.B. 18 if the power requested is lower than 40% of the maxi- mum power output then control is achieved by switch- ing on the burner at minimum power, then switching off (on/off function). If the power requested is higher, then the burner is switched on at maximum power and will...

  • Page 21

    Electronic control p.C.B. 19 a short pulse every 4 seconds boiler in stand---by condition. (function control in position). Anti---freeze system active. 1 second on 1 second off boiler on condition (function control in or position) with the boiler switched on ( or ) all the lamps (7 in fig. 29) are a...

  • Page 22

    Electronic control p.C.B. 20 10.6 settings two setting jumpers are fitted on the electronic control p.C.B. Refer to fig. 36 for the position of the jumpers. The numbers refer to the marking printed on the circuit board. 1 2 3 4 5 6 7 8 9 fig. 36 the device n indicated in fig. 37 and marked “risc” on...

  • Page 23

    Electronic control p.C.B. 21 8 insert the spindles in the control panel knobs un- till the notch a (fig. 39) reaches the potentio- meter edge. It is not necessary to force them in the knob. 9 while tightening the screws that fix the electronic control p.C.B. On the control panel, keep the p.C.B. Tow...

  • Page 24

    Electronic control p.C.B. 22 10.10 thermal control in the ” ” mode see functioning with the function control in the mode (sec. 10.11) taking water from the domestic hot water circuit? Switch in the function mode no yes is primary circuit temperature higher than that selected? No request for heat fro...

  • Page 25

    23 11 full sequence ignition device 11.1 function the full sequence ignition device used on the boiler carries out the following fundamental functions: f does a sequence of operations (ignition cycle) which lead to the ignition of the gas at the burner f checks the presence of the flame during the e...

  • Page 26

    Full sequence ignition device 24 11.4 ignition and control sequence lock memorised? Supply from the electronic control circuit air pressure switch at rest? No no starts fan yes air pressure switch at work? No beginning of wait period presence of flame? No yes yes air pressure switch at work? No yes ...

  • Page 27

    25 12 modulating gas valve 12.1 function the modulating gas valve a in fig. 44 controls the gas inflow to the boiler burner. A fig. 44 by means of an electric command given to the on---off operators the passage of the gas through the modula- ting gas valve can be opened or closed. By means of an ele...

  • Page 28

    Modulating gas valve 26 12.4 checks warning: isolate the boiler from the mains electricity supply before removing any covering or component. N check the modulation operator coil 1 remove the front panel of the case. 2 disconnect the connectors b (fig. 48) from the modulating operator and measure the...

  • Page 29

    27 13 primary circuit flow switch 13.1 function the primary circuit flow switch ( a in fig. 49) function is to detect water flowrate through the primary hydraulic circuit of the boiler. A i fig. 49 this hydraulic/membrane operated electrical micro--- switch device will control the functioning of the...

  • Page 30

    Primary circuit flow switch 28 e f g h fig. 53 4 reassemble the parts in reverse order of removal. When assembling the membrane, ensure that its concave side faces towards the actuator plate g and the reference indicated aligns with the seat h (see fig. 53). 14 expansion vessel and temperature---pre...

  • Page 31

    29 15 d.H.W. Flow switch, filter and flow limiter 15.1 function the d.H.W. Flow switch a in fig. 57 is a device that gener- ates an electrical signal when hot water is drawn. A fig. 57 when the flow rate through the d.H.W. Circuit reaches about 2,5 litres/min’, the float 4 (fig. 59) is drawn to- war...

  • Page 32

    D.H.W. Flow switch, filter and flow limiter 30 2 remove the flow switch sensor (see section 15.4). 3 remove the gas valve (see section 12.6). 4 unscrew the plug 2 (fig. 59) and extract the flow switch group. 5 to remove the filter from the flow switch group separate the body 7 from the plug 2 (fig. ...

  • Page 33

    31 16 temperature probe 16.1 function the temperature probe has the function of converting the temperature of the water in the hydraulic circuit where it is installed into an electrical signal (resistance). The relation between temperature and electrical resis- tance is stated in fig. 62. 500 1000 1...

  • Page 34

    32 17 by---pass valve 17.1 function the by---pass valve a in fig. 65 is located between the c.H. Water flow and return and its function is that of guar- anteeing a minimum flow across the primary heat ex- changer if the circulation across the c.H. System is com- pletely closed. The by---pass valve i...

  • Page 35

    33 18 fan, venturi device and air pressure switch 18.1 function the function of the fan a (fig. 67 and fig. 68) is to force the products of combustion trough the condensing heat exchanger to the outside air via the flue system. The fan is supplied by the full sequence ignition device at the beginnin...

  • Page 36

    Fan and air pressure switch 34 n.O. N.C. ”l” connection com ”h” connection fig. 69a ”l” connection ”h” connection fig. 69b n check of the venturi device this test must be carried out with the sealed chamber closed 1 remove the caps of the pressure test points lo- cated on the top of the boiler and c...

  • Page 37

    Fan and air pressure switch 35 18.4 inspection and removal of the venturi device warning: isolate the boiler from the mains electricity supply before removing any covering or component. 1 remove the fan (section 18.3). 2 remove the venturi device by unscrewing the screw h. 3 inspect the venturi devi...

  • Page 38

    36 19 ignition and detection electrodes 19.1 function three electrodes are fitted on the burner. Two of them are the ignition electrodes and are fitted near the front part of the burner. The ignition sparks take place be- tween their metallic edges over the central ramp of the burner during the igni...

  • Page 39

    37 20 safety thermostat 20.1 function the safety thermostat a in fig. 77 and fig. 78 is a de- vice that senses the temperature of the primary circuit water which flows in the outlet pipe of the primary heat exchanger. If the temperature control system of the boiler fails and the temperature of the p...

  • Page 40

    38 21 flue thermostat 21.1 function the flue thermostat a in fig. 80 and fig. 81 senses the temperature of the combustion products that flow through the condensing heat exchanger. A fig. 80 in the case that the temperature of the combustion products reaches a potentially dangerous value, it stops th...

  • Page 41

    39 22 condensate trap 22.1 function the condensate trap a in fig. 83 and fig. 85 allows the discharge of the condensate via the condensate drain pipe avoiding in the mean time the escape of combus- tion products. A plastic ball closes the trap outlet in case that the trap is empty. A fig. 83 the con...

  • Page 42

    40 23 short spare parts list key g.C. Part no. Description q.Ty manufac- turer part no. Manufacturer’s reference 1 173---148 burner (mod. M96.24sm/...,) 1 ki1004 102 polidoro 1 173---149 burner (mod. M96.28sm/...,) 1 ki1004 147 polidoro 2 169---069 injectors for natural gas (mod. M96.24sm/..., ) 12 ...

  • Page 43

    Short spare parts list 41 1 2 6 4 5 7 3 8 15 18 12 13 20 22 23 24 26 27 14 16 25 17 19 9 10 11 9 21.

  • Page 44

    *1796210720* 17962.1072.0 2404 44a4 uk biasi u.K. Ltd unit 31/33, planetary road industrial estate, neachells lane willenhall, wolverhampton wv 13 3xb technical helpline: 01902 304 400 web site: www.Biasi.Co.Uk.