SERVICE MANUAL GARDA M90F.24S M90F.28S M90F.32S
Contents
1. Le Fig 41 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 electric command given to the modula tion operator the pressure can be varied and therefore the gas flow rate to the burner modulation The mo dulation operator has mechanical components which allow the adjustment of the minimum and maximum pressure exiting the valve EJ Nomenclature of the parts Fig 42 1 Modulation operator s electric connectors Minimum gas pressure adjustment On off operators Maximum gas pressure adjustment On off operators electric connector Gas valve inlet pressure test point Modulation operator oN O O OO N Gas valve outlet pressure test point Fig 42 EDEM Adjustment NN Warning isolate the boiler from the mains electricity supply before covering or component removing any 1 Remove the front panel of the case 2 Open the gas valve inlet pressure test point 6 in Fig 42 at the valve input connect a suitable pressure gauge and check the gas pressure of the s2. AN r 2 bclic 3 N r r A Xt to gim c ft DHW temperature DHW flow bH temperature Primary ILI b probe NTC switch probe NTC pressure switch l Three way diverter valve Time switch Pump m brown b white a orange c blue r red g yellow n black gr grey g v yellow green v green Diagrams EPA Wiring diagram M90F 24SR M90F 28SR Wiring diagram for boiler equiped with full sequence ignition device type ceza Electrical Fan Air pressure Safety Flame detection ignition supply terminal switch thermostat electrode electrodes block COM LON PAN 7 ahh m gv c id rat m LOC __ YN J a TITI Gaoli OS al eee iat EE Modulating gas valve LI DO J11 N Lan S C Noe P CH temperature Primary LI bode probe NTC pressure switch Time switch Pump m brown b white a orang
3. Fig 9 The hydraulic circuit is composed of 8 elliptical pipes connected in parallel Fig 10 Fig 10 EP Removal NN Warning isolate the boiler from the mains electricity supply before removing any covering or component Empty the primary circuit of the boiler 2 Remove the case panels and the sealed chamber lid see section 2 3 Remove the combustion chamber lid B by un screwing the screws C Fig 11 3b For model M90F 28S M90F 28SR and M90F 32S only remove the screw D and the plate E 4 Remove the clips F and the safety thermostat G Itis not necessary to disconnect it from the wiring 10 5 Unscrew the connection H Fig 12 lift the pipe l and rotate it right then move it downwards free ing it from the heat exchanger connection 6 Remove the motor of the three way diverter valve see section 8 3 7 Completely unscrew the connection J and rotate the pipe K downwards freeing it from the heat ex changer connection 8 Remove the heat exchanger by sliding it for wards 9 Reassemble the boiler carrying out the removal operations in reverse order Fit the clips F with the arrow pointing upwards as illustrated in Fig 11 Fig 12 EEN Cleaning If there are deposits of soot or dirt between the blades of the heat exchanger clean wi
4. 27 FUNCHOM ces ee ee oe abo a 27 Nomenclature of the parts 27 Adjustment aree ne ane eee eee 27 GheCKS pea ences ee Scan a 28 Removal of the on off operators coils 28 Removal of the gas valve 28 Primary circuit flow switch 29 FUNCION book e s wa Eb 29 Check ot eee Pee eee 29 Removal usya cee cede ta ua is 29 Expansion vessel and temperature pressure gauge 30 FUNCUOM nie tama cae tite ase 30 Checks eae otk ee halo ee anaes 30 Removal of the expansion vessel 30 Removal of the temperature pressure AU GO 1 akote den ao dea we Ped de ae EA D h w flow switch filter and flow limiter 31 EUACHON tehas mas an a mea u Sg Ca dren 31 Nomenclature and location of parts 31 Gheek eof ss ry oes Be N lavi Ba ae 31 Removal of the flow switch sensor 31 Removal of the flow switch group and d h w circuit filter 31 Flow limiter w pie lakwa avek wate 32 Temperature probe 33 Function 33 CHECKS 2 n sat huayu tia gone war ag 33 Removal 2 7 eenas verite avan bd YY 33 By pass valve 34 FUNCUOM 0 583 yp taf ke a i ead 34 Removal secede eis eee ond hee 34 Fan venturi device and Air pressure switch 35 Function 1 35 CHECKS E bh u au tama Sw akor 35 Removal of the Fan 36 Inspection and removal of th
5. 1 Remove the front and left hand side panels of the case turn off the flow and return isolation valves and empty the primary circuit 2 Completely unscrew the connection K the lock nut L Fig 52 and remove the expansion vessel from the top of the boiler 3 Re assemble the parts in reverse order of re moval EBXZM Removal of the temperature pressure gauge 1 Remove the front and right hand side panels of the case turn off the flow and return isolation valves and empty the primary circuit 2 Remove the fork M and the probe holder spring N Fig 58 3 Squeeze the tabs O to release the temperature pressure gauge P and remove it 4 Re assemble the parts in reverse order of re moval Fig 53 25 13 D h w flow switch filter and flow limiter EENI Function The d h w flow switchA in Fig 54 is a device that gener ates an electrical signal when hot water is drawn e en a GO Fig 54 When the flow rate through the d h w circuit reaches about 2 5 litres min the float 6 Fig 56 is drawn to wards the right The
6. between the pump and the brass group 8 Three way diverter valve EIN Function The diverter valve A Fig 20 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 orderto send the water that exits the primary heat ex changer towards the c h system or towards the d h w heat exchanger 2 D pe e pre a x Fig 20 EEJ Checks yo Check the electrical continuity Fig 21 indicates the relationship between the electric command coming from the electronic control p c b and the position of the actuator B brass spindle when the boiler operates in d h w mode Fig 22 indicates the relationship between the electric command coming from the electronic control p c b and the position of the actuator B brass spindle when the boiler operates in c h mode In both figures the relationship between the position of the actuator and the resistance of the motor windings the motor must be disconnected from the wiring is also given Spindle B not visible Se Q ke A a p 9 4 Kohm bn brown Open circuit bu blue tee 23 e bk black 2 e g gt alo Fig 21 D h w mode B sy Spindle B visible L D oO a D Open circuit bn brown 9 4 Kohm bu blue 5 pea a bk black iS gt o Q Fig 22 C h mode EE Remov
7. Wall hung fan flue room sealed gas boiler SERVICE MANUAL GARDA Models G C Appl No M90F 24S 47 970 19 M90F 28S 47 970 20 M90F 32S 47 970 22 M90F 24SR 41 970 10 M90F 28SR 41 970 11 Leave this manual adjacent to the gas meter Biasi UK Ltd Newman Park Western Way Wednesbury WS10 7BJ Sales Tel No 0121 506 1340 Sales Fax No 0121 506 1360 Service Tel No 0121 506 1350 Service Fax No 0121 506 1370 www biasi co uk Z BIASI Table of contents w M Overall information 2 Overall View 2 Hydraulic diagram 2 General access and emptying hydraulic circuits 3 Nomenclature 3 Body panels 3 Control panel 3 Access to the sealed chamber 4 Emptying the primary circuit 4 Emptying the d h w circuit 4 Diagrams 5 Wiring diagram M90F 24S M90F 28S M90F 32S 5 Wiring diagram M90F 24SR M90F 288R 7 Functional flow diagrams 9 Circuit voltages 10 Fault finding 12 Primary heat exchanger 14 Characteristics e 14 Removal icc acdc thai Sete 14 Cleaning 14 D h w heat exchanger 15 FUNCHONG wieder para ian aaa as 15 Removal seca mes enan vent qi
8. Injectors for natural gas M90F 32S Injectors for LPG mod M90F 24S M90F 24SR Injectors for LPG mod M90F 28S M90F 28SR Expansion vessel Main heat exchanger mod M90F 24S M90F 24SR Main heat exchanger mod M90F 28S M90F 28SR Main heat exchanger mod M90F 32S Fan mod M90F 24S M90F 24SR Fan mod M90F 28S M90F 28SR Fan mod M90F 32S Gas valve Air pressure switch 0 88 0 74 mbar mod M90F 24S M90F 24SR Air pressure switch 1 04 0 92 mbar mod M90F 28S M90F 28SR Air pressure switch 1 38 1 25 mbar mod M90F 32S Safety valve Combustion chamber side panels Combustion chamber rear panel mod M90F 24S M90F 24SR Combustion chamber rear panel mod M90F 28S M90F 28SR M90F 32S Combustion chamber front panel mod M90F 24S M90F 24SR Combustion chamber front panel mod M90F 28S M90F 28SR M90F 32S Electronic regulation p c b Full sequence ignition device D h w heat exchanger mod M90F 24S D h w heat exchanger mod M90F 28S M90F 32S Pump Primary circuit flow switch D h w flow switch Main flow switch membrane Three way diverter valve electric actuator Overheat thermostat Fuse 1 6AT Temperature probe main or d h w circuit Ignition electrode left mod M90F 24S M90F 24SR M90F 28S M90F 28SR Ignition electrode left mod M90F 32S Ignition electrode right mod M90F 24S M90F 24SR M90F 28S M90F 28SR Ignition electrode right
9. This allows you to select the minimum time that must pass between two ignitions of the burner in c h func tion 3 min ON 1 ig 1 OFF 0 30 sec Fig 34 N Setting jumpers Two setting jumpers are fitted on the Electronic starting control p c b Refer to Fig 35 for the position of the jumpers when the Electronic starting control p c b is fitted on a M90F 24S M90F 28S or M90F 32S boiler Refer to Fig 36 when the Electronic starting control p c b is fitted on a M90F 24S8R or M90F 28SR boiler The numbers refer to the marking printed on the circuit board 123456789 Fig 35 18 123456789 Fig 36 Ignition gas pressure adjustment By using the device 15 Fig 28 marked ACC on the Electronic starting control p c b it is possible to ad just the gas pressure at the injectors in the ignition phase This pressure is maintained at the injectors until ignition occurs ionization signal from the full sequence ignition device To carry out the adjustment move the function selector 3 to the OFF position Fig 33 and use the adjustment device 15 ACC Adjust the gas pressure at the injectors to the value indi cated in the tables of the User Installation manual Technical information section Gas pressures at the burner table By rotating the device clockwise the pressure in creases Check the regular ignition of the burner by turning the boiler on and
10. electricity supply before removing any covering or component 1 Remove all the case panels the sealed chamber lid and the combustion chamber lid 2 Disconnect the electrode wires from the full se quence ignition device 3 Remove the burner by unscrewing the four screws placed at the right and left sides of the burner 3b For models M90F 28S M90F 28SR and M90F 32S remove also the plate C see Fig 68 on page 32 4 Unscrew the screws A Fig 66 which hold the electrodes to the burner Two screws are used on the models M90F 24S M90F 24SR M90F 28S M90F 28SR Three screws one for each electrode are used on the model M90F 32S Ignition and detection electrodes 5 Extract the electrodes from the burner 6 Assemble the electrodes carrying outthe removal operation in reverse order Refer to Fig 63 in order to recognise the elec trodes and to correctly connect the wiring Note the metallic edge of the detection electrode is longer than the one of the ignition electrodes Warning After cleaning or replacement as detailed above refer to section Combustion analysis check in the chapter Maintenance of the installation instructions manual 31 17 Safety thermostat Function The safety thermostat A in Fig 67 is a device that senses the temperature of the primary circuit water which flows in the outlet pipe of the primary heat ex changer If the temperature control system of the boiler fails and the tempe
11. isolate the boiler from the mains electricity supply before removing any covering or component 1 Remove the front panel of the case and empty the 2 Remove the flow switch sensor see section Nominal flow rate litres min 13 4 3 Unscrew the body 2 Fig 56 and extract the flow To install the threaded ring with the flow limiter switch group 1 Remove the flow switch group as explained in the 4 To remove the filter from the flow switch group section 13 5 separate the filter 9 from the threaded ring 2 Fig 56 by levering it Remove the filter from the flow switch group 5 Reassemble the parts following the removing se 3 Unscrew the threaded ring 7 Fig 56 and re quence in reverse order move it from the body 2 13 6 Flow limiter 4 Reassemble the group following the above se quence in reverse order The M90F 24S model is factory fitted with a 10 litre min flow limiter 27 14 Temperature probe EAN 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 57 Q 12500 12000 11500 11000 10500 10000 9500 9000 8500 8000 p 7500 7000 6500 6000 5500 5000 4500 4000 3500 3000 2500 gt 2000 m 1500 1000 500 20 25 30 35 40 45 50 55 60
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13. Remove the spindles of the c h and d h w tem perature adjustment knobs by delicately pulling them with pliers in the direction shown by the arrow in Fig 37 4 Unscrew the four screws that hold the Electronic starting control p c b on to the control panel 5 Remove it by lifting its rear edge and freeing it from any of the wiring 6 Re assemble the Electronic starting control p c b following the removal procedures in the re verse order Important When re assembling the Electronic starting control p c b 7 Fit the p c b into the control panel by first insert ing the front lower edge under the control knob shafts Lower the rear edge and ensure that no wiring is trapped beneath Insert the spindles in the control panel knobs un till the notch A Fig 38 reaches the potentio meter edge It is not necessary to force them in the knob While tightening the screws that fix the Electronic starting control p c b on the control panel keep the p c b towards the control panel fascia mak ing sure of the contact between the boiler reset button B and the tab C Fig 38 sss E Attention After 10 11 installing the Electronic starting control p c b Make sure the c h w and d h w BA tem perature adjustment knobs can move freely for the complete range If not remove the spindle again as described at step 3 turn the knob half a turn and re insertthe spindle Operat
14. check and maintenance oper ations it is necessary to remove one or more panels of the case The side panels can be removed only after the removal of the front panel To remove the front panel remove screws A Fig 2 lift the panel and remove it Fig 2 To remove the side panels loosen the screws B and C Fig 3 bring the base of the panels away from the boiler and lift them freeing them from the top hooks Fig 3 bottom view of the boiler PEW Control panel NN Warning isolate the boiler from the mains electricity supply before removing any covering or component To gain access to the parts located inside the control panel proceed as follows 1 Remove the front panel of the case Loosen the screws B and C Fig 3 Remove the screws D O MN Move the lower part of the side panels as indi cated in Fig 4 and pull the control panel When completely pulled out the panel can rotate 45 downwards to facilitate the service oper ations on the internal parts 3 General access and emptying hydraulic circuits Fig 5 Remove the screws E and remove the service panel Fig 5 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 Fig 6 To gain access to the parts contained in the sealed chamber it is necessary to remove the lid of the sealed cha
15. mis 15 POMP e rit maron ta aaa oaa pe a aah a 16 FUNCOM stent chi et poem 16 CGH CKS vs as eet eine pk anana 16 Removal uuu u uY Se Ses 16 Three way diverter valve 17 UIC OM 3 ee kayo ta etoile tacana 17 Checks vs aaa anan n e mean wae 17 Removal of the electric actuator 17 Removal of the diverter group anditsinternal partS 18 Electronic control p c b 19 FUNCUON y eee takse bat a a yu ian 19 Selection and adjustment devices 19 Checking the temperature 19 Operation Service lamps 20 Dip switch selectors 21 Setting jumpers 22 Ignition gas pressure adjustment 22 Max c h power adjustment 22 CHECKS 2 3 ay cere hal ea sc yon 22 Removal of the electronic control p c b 22 Thermal control in the ee mode 24 Thermal control in the Be mode 24 Full sequence ignition device 25 FUNCHON aani naai s gua aa i 25 10 2 10 3 10 4 11 11 1 11 2 11 3 11 4 11 5 11 6 12 12 1 12 2 12 3 13 13 1 13 2 13 3 13 4 14 14 1 14 2 14 3 14 4 14 5 14 6 15 15 1 15 2 15 3 16 16 1 16 2 17 17 1 17 2 17 3 17 4 17 5 18 18 1 18 2 18 3 19 19 1 19 2 19 3 20 GRECKS tr cscs alates aa u xa the anita quni 25 Removal oly dt u k u ke Ie eee ay 25 Ignition and control sequence 26 Modulating gas valve
16. mod M90F 32S Q ty 14 16 12 14 Manufac turer part no KI1004 102 KI1004 147 Bl1193 100 KI1064 505 Bl1193 500 KI1064 506 BI1172 103 BI1202 101 BI1202 102 BI1222 100 Bl1366 102 Bl1366 103 Bl1376 105 Bl1193 105 KI1267 103 Bl1366 107 Bl1376 104 Bl1131 100 Bl1326 100 Bl1326 107 Bl1326 108 Bl1326 101 Bl1366 109 Bl1515 107 Bl1305 101 Bl1001 101 Bl1001 102 Bl1272 100 Bl1011 505 Bl1091 104 Bl1011 103 Bl1101 102 Bl1172 105 Bl1005 105 Bl1001 117 Bl1123 101 Bl1193 102 Bl1123 103 Bl1193 103 Manufacturer s reference Polidoro Polidoro CIMM 6 litres FIME GRO2040 39W FIME GRO2045 47W FIME GRO2050 60W SIT 845 Sigma Yamatake Honeywell C6065 SIT 380 alternative Watts Orkly alternative Bertelli amp Partners FM30 Honeywell FPLD alternative WSC NFSL 12 5 Elbi ELTH type 261 33 Short spare parts list Y i st oo o e e o N t m m ga an a N Li a 21 AE koi ald EJL 12 oO 3 8 O gt O I jo L 212 S E Ola 2 o ar To l o Oo Li a 25 E83 122 Detection electrode mod M90F 28S M90F 28SR 34 17962 0918 7 4006 44A4 UK
17. modulation operator coil Remove the front panel of the case Disconnect the connectors B Fig 45 from the modulating operator and measure the electrical resistance of the coil Its electrical resistance value must be approx 80 Q Check the on off operators coils Remove the front panel of the case Disconnect the electrical connector C Fig 45 Measure the electrical resistance between the connector pins of the on off operators as illus trated in Fig 43 NENN Qs Upper on off operator approx 6 400 Q Lower on off operator approx 920 Q at ambient temperature Fig 43 EDEM Removal of the on off operators coils NN Warning isolate the boiler from the mains electricity supply before removing any covering or component 1 Remove the front panel of the case as explained in the section 2 3 of this manual 2 Disconnect the connector D Fig 44 3 Unscrew the screw E and remove on off oper ator coils 4 Reassemble the coils carrying out the removal operations in reverse order AJ Removal of the gas valve NN Warning isolate the boiler from the mains electricity supply before removing any covering or component 1 Remove the front panel of the case as explained in the section 2 3 of this manual 2 Disconnect the connectors B and C Fig 45 3 Turn off the gas supply and disconnect the gas isolation cock connector from the inlet port of the gas valve 4 Unscrew the connectors F and
18. off repeatedly After the adjustment operations bring the selector 3 back to the normal position ON EM Max c h power adjustment By using device 16 Fig 28 marked RISC on the Electronic starting control p c b you can limit the maxi mum useful output delivered during the c h operating mode This adjustment does not influence the maxi mum useful output delivered during the d h w operat ing mode By rotating the device clockwise the pressure in creases EX Checks yo Check that the fuse is complete If the Electronic starting control p c b does not supply any device pump fan etc check that the fuse 2 Fig 28 is complete If the fuse has blown replace it with one that has the same characteristics after having identified the reason for failure yo Check the setting jumpers position Two setting jumpers must be fitted on the Electronic starting control p c b as shown in Fig 35 EXE Removal of the electronic control p c b NN Warning isolate the boiler from the mains electricity supply before removing any covering or component 1 Gain access to the parts located inside the con trol panel as explained in the section 2 3 of this manual 2 Remove all the wiring connected to the Electronic starting control p c b Electronic starting control p c b To disconnect the connectors J1 J3 J7 J15 J16 and 5 1 8 14 and 6 in Fig 28 delicately flex the hook present on one side of each socket
19. resulting magnetic field of ring 5 increases and re aches the flow switch sensor 1 The sensor generates an electrical signal that switches the boiler d h w operation ON The state of the sensor is also indicated by means ofthe lamp B placed on the sensor body IEEJ Nomenclature and location of parts Fig 56 Flow switch sensor Body O ring Spring Magnetic ring Float Threaded ring Flow limiter optional accessory Filter 0 Spring seat OMAN O OQ Q NN Fig 56 EEN Checks NN Warning isolate the boiler from the mains electricity supply before removing any covering or component Y Flow switch sensor operation 1 Remove the front panel of the case 2 Switch on the boiler and open a d h w tap The lamp B Fig 55 placed on the sensor body is switched on when the flow rate reaches about 2 5 litres min KEZM Removal of the flow switch sensor NN Warning isolate the boiler from the mains electricity supply before removing any covering or component 1 Remove the front panel of the case 2 Disconnect the connector C Fig 55 and remove the sensor by delicately livering downwards with a screwdriver D h w flow switch filter and flow limiter IEEJ Removal of the flow switch group and Ifon the M90F 28S model the flow rate of the d h w cir d h w circuit filter cuit is too high it is possible to limit it by installing a flow limiter The following sizes are available NN Warning
20. 65 70 75 80 85 90 95 100 C Fig 57 On the boiler there are two Temperature probes One on the output ofthe primary heat exchanger c h Tem perature probe A in Fig 58 and Fig 59 one on its input before the pump d h w Temperature probe Bin Fig 58 and Fig 60 ou jr X E GO l al z P Essl usa Fi f a ME c h inlet return oi d h wA outlet Fig 58 28 EEJ Checks ye Temperature resistance relationship NN Warning isolate the boiler from the mains electricity supply before removing any covering or component Disconnect the cable from the Temperature probe Measure the temperature of the brass group where the Temperature probe is located and check the electrical resistance according to the graph in Fig 57 EEN Removal NN Warning isolate the boiler from the mains electricity supply before removing any covering or component Refer to Fig 59 for the c h Temperature probe and to Fig 60 for the d h w Temperature probe 1 To remove the Temperature probes remove the front and right hand side panels of the case 2 Empty the primary circuit of the boiler 3 R
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22. al of the electric actuator NN Warning isolate the boiler from the mains electricity supply before removing any covering or component 1 Remove the front case panel 2 Disconnect the connectors C Fig 23 3 Remove the fixing spring D and remove the actuator E Reassemble the actuator carrying out the re moval operations in the reverse order When reassembling the actuator refer to Fig 21 or to the wiring diagram in section 3 1 for the cor rect wiring connection 13 Three way diverter valve Fig 23 EZI Removal of the diverter group and its internal parts 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 8 3 4 Remove the fixing spring F Fig 24 and remove the primary circuit flow switch G 5 Disconnect the c h temperature probe H 6 Unscrew the connector the c h flow connector and the d h w outlet connector 7 Remove the d h w heat exchanger see section 6 2 8 Remove the fork J and move away the pipe K Fig 25 14 9 Unscrew the screw L and remove the diverter group Fig 25 Rear view of the boiler 10 Refer to the exploded view in Fig 26 to remove the internal parts of the three way diverter valve Fig 26 11 Reassemble the diverter group carrying out the removal operations in the reverse order 9 Electronic s
23. e venturi device 36 Removal of the Air pressure switch 36 Ignition and detection electrodes 37 FUN CHOM soo cece ene area nqa u a Reaves 37 GREGCKS Ye ate ye etan Goatees dace ano sasa 37 REMOVAl excesses ese cats panes owa 37 Safety thermostat 39 F nG8tI rTy titre aaa tiket Se eee cack 39 Checks soccer Sarde Ree s 39 Removal i usya saus oot eae 39 Short spare parts list 40 1 Overall information R Overall View Air pressure switch Fan x Main heat Expansion exchanger vessel a Safety i thermostat Burner Combustion chamber Ignition electrodes Detection electrode Diverter vave u A Automatic air release D h w pi valve heat exchanger Main circuit flow switch D h w temp probe all Gas valve 4 Pump I Control D h w panel kon flow switch me a REM Hydraulic diagram Central heating c h operation Domestic hot water d h w operation M aa C h C h D h w D h w water return water flow inlet outlet 2 General access and emptying hydraulic circuits ENN Nomenclature Fig 1 Right side panel Front panel Control panel lid Control panel cover Service panel O a OO PN Left side panel EEJ Body panels NN Warning isolate the boiler from the mains electricity supply before removing any covering or component For the most part of the
24. e c blue r red g yellow n black gr grey g v yellow green v green Diagrams Circuit voltages Eletric supply 3 way diverter terminal block valve Fan 2 pe 230 n Ne A DN amp 5 8 Pump Modulating Safety Gas valve thermostat during c h or d h w operation Electrical voltages with burner on CD only during c h operation an only during d h w operation uonounj w y p uo uolle19do eLLION 9 9 H y o uo JIUA LOUS B JO SIYEN Jeogeyj Y I Y o uo ll9 uo2 s le1 do 1 l ioq ay s ewej ou Jo uone npoui y UO Peye 1 useu qouy jueunsnipe dwa w u p ou Buruan 2 enjeledwe 2 H H M U P AU Ionmuoo 1 us op J lloq ayi uin11 us op uej epou wy p E E R H H H 10 y o ul aayy 1uBI 1Lus op JeUING eyj un Uey epou w y p H H 10 y o ul J ull 146 1 us op Jeunq eyj ureBe O O z z SOO Jejioq oui pue nunuoo syueds i uous y uo syi 12u1nq yL me e oAJ UONIUBI ayi sugs Jojioq o m H H Hig y uopnq ysnd ese oui Guisse d Ag 5 ureBe sy20 D Jejioq 84 pue enunuoo syseds uon o 1U6G1 y uo 1uBil 1 USYOop unq u l aj0A0 uous ayi sugs J jioq H H H H y uopnq ysnd 18s 1 oui Guisse d Ag 2 Apoe 100 sejeledo pue uo suin Jejioq Hig H H H y uopnq ysnd 18s 1 oui Guisse d Ag asueqy O O pow wyp a A E
25. e configur ation in which the boiler is set in the factory natural gas boiler Minimum gas pressure adjustment Gas conversion Ignition gas pressure adjustment E Reignition frequency 1 12 4 ku N BL ofr 0 13 Fig 31 O Selector 1 This forces the boiler to operate at the minimum gas pressure in order to allow the adjustment of the mini mum gas pressure at the burner on the modulation op erator of the gas valve 17 Electronic starting control p c b After any adjustment operation the selector has to be brought back to the normal position ON O Selector 2 This selects the boiler functions on the basis of the type of gas used It allows the selection of the maximum supply current given to the modulator device To set selector 2 correctly follow the table in Fig 32 Gas supply Position of selector Approx Max current through the modu lator device Natural gas 120 mA L PG 165 mA Fig 32 Selector 3 This forces the functioning of the boiler in order to allow the optimal gas pressure at the burner to be adjusted during the ignition phase The adjustment see section 9 7 is done by means of the potentiometer 15 marked ACC Fig 28 on page 15 After the adjustment operations bring the selector back to the normal position ON ON 1 OFF 0 gas pressure calibration Normal Fig 33 O Selector 4
26. e the boiler and close the gas inlet cock so that the boiler goes into the safety lock out state Verify the correct operation of the boiler reset but ton by pressing and releasing it Warning After cleaning or replacement as detailed above refer to section Combustion analysis check in the chapter Maintenance of the installation instructions manual 19 Electronic starting control p c b CREN Thermal control in the amp mode NO See functioning with the function Taking control in they mode lt YES water from the domestic hoD gt NO water circuit2 Is primary circuit temperature higher than that selected sec 9 12 Circulator off Operates motorised valve Starts the circulator Request for heat from YES Operates motorised valve room thermostat Ignition device off Supplies the ignition device YES lock memorised NO w YES Y Air pressure switch at rest Air pressure switch at work NO YES beginning of wait period presence of flame YES L NO Air pressure switch at work YES starts ignition discharges opens gas valve beginning of ignition period NO flame presence YES closes gas valve d of igniti stops fan L NO ene Ob anon interrupts ignition discharges memorizes lock turns on l
27. emove the electric connector of the Tempera ture probe and unscrew it 4 Reassemble the Temperature probe carrying out the removal operations in reverse order Fig 60 15 By pass valve HEJ Removal HAN Function NS Warning isolate the boiler from the mains The By pass valve A in Fig 61 is located between the electricity supply before removing any c h water flow and return and its function is that of guar covering or component anteeing a minimum flow across the primary heat ex changer if the circulation across the c h system is com 1 Remove all the case panels pletely closed 2 Empty the primary circuit of the boiler The By pass valve is fitted on the rear side of the div erter group Remove the diverter group as described in the section 8 4 of this manual A lt lt 4 Unscrew the connector B and remove the by 1 A pass valve C Fig 62 X E GO J m o t A W Fig 62 X 5 Reassemble the by pass valve as illustrated in Fig 61 Fig 62 reversing the order of removal 29 16 Ignition and detection electrodes HAN Function Three electr
28. erthe pump operates it does not activate with in 20 seconds the control board will indicate that a fault condition see section 9 4 ofthis manual has occurred EN Checks NN Warning isolate the boiler from the mains electricity supply before removing any covering or component ye Mechanical function Remove the front panel of the case 2 Start and stop the boiler either in d h w or c h mode 3 Looking through the switch box verify the position of the shaft B referring to Fig 48 Boiler OFF B Fig 48 Boiler ON 4 Electrical check It is possible to verify the general operation of the switch by measuring the electric resistance between the con tacts C and N O of the switch 1 Remove the switch as explained in section 11 3 2 Measure the electrical resistance between the tabs marked C and N O Fig 49 The contact must be normally open 3 Operate the switch by hand and verify that the contact is now closed C No X x do not use Fig 49 HEN Removal NN Warning isolate the boiler from the mains electricity supply before removing any covering or component x Removal of the switch 1 Remove the front and right hand side panels of the case 2 Remove the fork C Fig 47 3 Open the box and disconnect the switch 4 Re assemble the parts in reverse order of re moval Refer to Fig 49 for the correct wiring con nectors on the switch yw Removal of the membrane 1 Remove the fr
29. ft side of the boiler Fig 16 17 7 Pump Function The pump A in Fig 17 has the function of making the waterinthe main circuit circulate through the main heat exchanger and therefore through the c h system dur ing the c h function or through the secondary heat ex changer during the d h w function pet sl 3 J Fig 17 Checks NN Warning isolate the boiler from the mains electricity supply before removing any covering or component ye Check that the pump is not seized and that the movement of the rotor is not subject to mechanical im pediments With the boiler off remove the front panel Remove the air release plug of the pump and turn the rotor with a screwdriver yo Check the electrical continuity With the boiler off remove the front panel and discon nect the connector B Fig 18 Measure the electrical resistance between the pump supply connections Electrical resistance of the windings at ambient tem perature must be about 230 Q ye Check the absence of starting defects With the boiler off remove the front case panel Remove the air release plu
30. g from the pump Start the boiler and with a screwdriver turn the rotor in the direc tion of the arrow If there is a defect in starting the rotor ye Check that the impeller is integral with the rotor With the boiler off remove the front and right hand side case panels lower the control panel and empty the pri mary circuit Remove the pump head by undoing the screws which hold it to the pump body and check that the impeller is firmly joined to the rotor Removal NN Warning isolate the boiler from the mains electricity supply before removing any covering or component Remove the front and right hand side case panels Empty the primary circuit of the boiler Extract and lower the control panel Disconnect the connector B Fig 18 Unscrew the connection C and move the pipe up wards freeing it from the outlet port of the pump Remove the fork D and the capillary pipe 7 Remove the locking plate E right Fig 18 aR OQ N O 8 Loosen the connection F remove the fork G and the pipe H 9 Unscrew the two screws that hold the pump on the frame Fig 19 and remove the pump towards the front of the boiler Fig 19 Reassemble the pump carrying out the removal oper ations in the reverse order When reassembling the pump check the correct location of the O ring gasket in the inlet port of the pump that seals the connection will begin to turn normally only starting it manually 12
31. g pjoo w u p Ajddns jou seop Jejioq y olj oOt mis o fo a 2 J v B iw Oln Di TMmo poo UOU ulJ o al a v a S 8 F R S TZ S S S S Z S F 8 8 S Z Z S S S S S S S 8 S 5 58 g 3 8S S S E sS ES Z E 52 E 2 s E B E S S Z F E a e 8 gt g dls S la s o F 8 da a s Z5 2 7 2 2 8 2 a 2 2 gt o 8 l lt o Qs a 8 Se 8 5 s 213 8 8 8 S S 8 3 E 8 2 S 133 lt 3 Z a o S s Z Zis es 82 s a ao g a amp v 30 8 2 8 s S E s S ca ESE Si AE 8 28 2 B SO S ZZ S EE ole s ST 3 a ITS 2 BiISg o G a o a Z l Z s SF D 2 ejg SIZ oa g a a D ej 8 S j 8 E8 Z E DY i Q ae allal a s lt s t 2 109jaq 6 8 9 2 g 2 sjexoe q ul you ajou _ fezZti ai OVLON SL chi S ELIZC LLH tot 6 6 c8 clZ 9 3 m enuew ou JO UONLBS y y 0 sjueUOdWoj O 5 Primary heat exchanger BAM Characteristics The primary heat exchangerA in Fig 9 has the function of transferring heat produced from combustion of the gas to the water circulating in it E E GO 2 22 CHES l
32. ion and adjustment devices On the Electronic starting control p c b several selec tion adjustment and protection devices are located Fig 28 Some of these devices are directly accessible by the user function control temperature adjustment poten tiometers etc others are accessible by removing the service panel or the control panel lid Fig 28 Connector J1 electric supply terminal block Fuse F1 3 15A 250V Connector J3 Pomp three way diverter valve Connector J16 Modulating gas valve Connector J19 Flame detection electrode Connector J15 Fan Air pressure switch Safety thermostat 7 Connector J20 e J21 Ignition electrodes 8 Lock out signal lamp 9 Boiler reset button 10 Function control C h temperature adjustment O O G NN 11 Connector J7 15 Electronic starting control p c b 12 D h w temperature adjustment 13 Dip switch selectors 14 Operation lamps 15 Ignition gas pressure adjustment ACC 16 Maximum c h gas pressure adjustment RISC EM Checking the temperature The Electronic starting control p c b makes it possible to separately adjust the c h water flow temperature and d h w outlet temperature The temperature of the water is converted into an elec tric signal by means of temperature probes The user setting the desired temperature with the con trol panel knobs operates the variable elements 10 and 12 in Fig 28 of the electronic contro
33. l p c b 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 control by modulating to 40 of the maximum power output During the c h operation Fig 29 the signal coming from the c h temperature probe is compared to the sig nal given by the control panel through the adjustment made by the user knob 81lB The result of such a com parison operates the modulation of the gas valve consequently changing the useful output of the boiler a2 lt P AY 7 we When the boiler functions in d h w Fig 30 the signal coming from the d h w temperature probe is compared with the signal given by the control panel through the adjustment made by the user knob 2 D e pe t X aa s 75 C poa l vy vv 1 amp 4 x AA AA amp L WA AN S ee O eee Fig 30 Normally the result of the comparison between these two signals directly operates the adjustment elements ofthe gas valve modulation device adjusting the useful output generated in order to stabilize the temperature of the exiting water If during the d h w mode operation
34. mber For this purpose remove the front and side panels of the case remove the screws G as indicated in Fig 6 and remove the lid BEN Emptying the primary circuit 1 Close the c h circuit flow and return cocks H Fig 7 Fig 7 bottom view of the boiler 2 Remove the front and right panels of the boiler 3 Open the drain tap Fig 8 until the boiler is com pletely emptied 4 Close drain tap again once the emptying has been completed ad pa li gt AN al ti a P j Fig 8 AJ Emptying the d h w circuit 5 Close the d c w inlet cock J Fig 7 6 Open one or more hot water taps until the boiler has been completely emptied 3 Diagrams ERM Wiring diagram M90F 24S M90F 28S M90F 32S Wiring diagram for boiler equiped with full sequence ignition device type ceza Electrical Fan Air pressure Safety Flame detection ignition supply terminal switch thermostat electrode electrodes loc COM block LON oly H K we le S m g v c g lA A N lA A a N g v giv ttt a als Li In L ay J ON lt e n g Ea EE re is 2 y L C mL grn SON be Nt BBB T Jen kape i Modulating gas valve MO ER y e 527
35. o Q Removal NN Warning isolate the boiler from the mains electricity supply before removing any covering or component 1 Remove all the case panels and the lid of the sealed chamber 1b For models M90F 28S and M90F 28SR remove the screw B and the plate C Fig 68 Lat a Pe TTE Fig 68 2 Disconnect the wiring D Fig 69 3 Remove the spring E which holds the overheat thermostat on the pipe of the primary heat ex changer and remove it 4 Reassemble the overheat thermostat carrying out the operations in reverse order 5 Apply an adequate quantity of heat conducting compound between the pipe and the thermostat Warning After cleaning or replacement as detailed above refer to section Combustion analysis check in the chapter Maintenance of the installation instructions manual 18 Shortspare parts list Key 1 11 12 13 14 15 16 17 18 19 20 21 22 23 24 G C part no 173 148 173 149 169 069 169 070 E83 121 E83 129 169 127 E83 013 E83 178 E83 180 E83 181 E83 196 E83 197 E83 142 E01 204 E01 205 E00 684 E83 082 E00 688 E83 086 E83 101 169 083 164 026 E83 127 E83 126 Description Burner mod M90F 24S M90F 24SR Burner mod M90F 28S M90F 28SR Burner mod M90F 32S Injectors for natural gas mod M90F 24S M90F 24SR Injectors for natural gas mod M90F 28S M90F 28SR
36. ock out light interrupts ignition discharges gas valve open NO reset push button YES pressed YES flame presence NO gt NO Safety thermostat YES opens the circuit l YES Air pressure switch at NO work Fig 39 20 Electronic starting control p c b ERP Thermal control in the B8 mode Switch in the 3 function mode n l Circulator off Circulator on aon NO gt Ignition device off Is domestic hot water outlet temperature lower than that required YES NO Ignition device off YES lock memorised NO L NO Air pressure switch at YES rest y NO Air pressure switch at YES work beginning of wait period presence of flame YES Air pressure switch at work YES starts ignition discharges opens gas valve beginning of ignition period NO flame presence YES closes gas valve n stops fan ke of ignition interrupts ignition discharges period memorizes lock turns on lock out light NO interrupts ignition discharges gas valve open NO reset push button YES pressed YES flame presence NO gt Safety thermostat opens the circuit NO YES Air pressure switch at work NO Fig 40 21 10 Modulating gas valve UAN Function The Modulating gas valve A in Fig 41 controls the gas inflow to the boiler burner
37. odes are fitted near the front part of the burner The ignition sparks take place between the me tallic edges of the ignition electrodes over the central ramp of the burner during the ignition sequence The third electrode is the detection electrode and it de tects the presence of the flame Fig 63 shows the electrodes configuration on the mo dels M90F 24S M90F 24SR M90F 28S M90F 28SR Fig 64 shows the electrodes configuration on the model M90F 32S Detection Male Fig 64 30 UE Checks yo Check the position of the electrode edges NN Warning isolate the boiler from the mains electricity supply before removing any covering or component 1 Remove all the case panels the sealed chamber lid and the combustion chamber lid 2 Check for the correct distance between the me tallic edges of the ignition electrodes see Fig 65 4mm AN Ignition lt Fig 65 3 Check the integrity ofthe detection electrode and ensure that its metallic edge is correctly placed over the ramp of the burner ye Check the connection wires NN Warning isolate the boiler from the mains electricity supply before removing any covering or component 1 Remove all the case panels the sealed chamber lid and the combustion chamber lid 2 Check for the integrity of the insulation of wires which connect the electrodes to the ignition de vice HEN Removal NN Warning isolate the boiler from the mains
38. ont and right hand side panels of the case turn off the flow and return isolation valves and empty the primary circuit 2 Remove the fork C that holds the micro switch housing D Fig 47 3 Unscrew the four screws E see Fig 50 open the hydraulic operator and remove the membrane F Fig 50 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 50 12 Expansion vessel and temperature pressure gauge EAN Function The Expansion vessel in Fig 46 function is to allow for the volume expansion of the c h circuit water due to the temperature rise EEN Checks 1 Turn off the flow and return isolation valves and empty the primary circuit of the boiler 2 Remove the protective cap J Fig 51 from the valve on the top ofthe expansion vessel and con nect a suitable air pressure gauge Fig 51 3 Check the pre load pressure and refer to the section Expansion vessel in the User manual and installation instructions for the correct value EBEN Removal of the expansion vessel If there is at least 400 mm clearance above the boiler and the rear exit flue can be easily removed the expan sion vessel can be changed without removing the boiler NN Warning isolate the boiler from the mains electricity supply before removing any covering or component
39. rature of the primary circuit reaches a dan gerous temperature the safety thermostat opens the electric circuit that supplies the on off operators of the gas valve Consequently the full sequence ignition device at tempts to light the burner and at the end locks the boiler and lights the lock out signal lamp ou e En a W A Ce Fig 67 Checks NN Warning isolate the boiler from the mains electricity supply before removing any covering or component Overheat temperature value Set the temperature control knobs to their max position and run the boiler in d h w and c h 2 Allow the boiler to reach its maximum operating temperature monitor the temperature gauge on the instrument panel The boiler should maintain a temperature below that of the safety thermostat and no overheat intervention should occur 4 Electrical function Remove all the case panels and the lid of the sealed chamber 2 Disconnect the safety thermostat and check its electrical function Normally no intervention the 32 contact must be closed electrical resistance zer
40. remove the pipe G 5 Unscrew the screws H and remove the valve 6 Reassemble the valve carrying out the removal operations in reverse order After any service operation on the components of the gas circuit check all the connections for gas leaks Warning After cleaning or replacement as detailed above refer to section Combustion analysis check in the chapter Maintenance of the installation instructions manual Fig 45 23 11 Primary circuit flow switch URN Function The Primary circuit flow switch A in Fig 46 function is to detect water flowrate through the primary hydraulic circuit of the boiler ou Ce gt X E GO Fig 46 This hydraulic membrane operated electrical micro switch device will control the functioning of the ignition control circuit providing there is an adequate quantity and flow of water in the primary circuit Any failure ofthe pump or obstructions in the primary circuit whilst in either c h or d h w modes will not allow the device to operate This device is connected to the electronic control p c b andif aft
41. service operation mode and all the lamps 14 in Fig 28 are then activated To reset the Electronic starting control p c b to the nor mal operation it is necessary to turn the knob tothe position or switch off the boiler for a short while at the fused spur isolation switch The following table gives the relationship between each of the possible lamp combinations and their meaning Electronic starting control p c b Normally operating boiler see the previous table for details z C h operation D n w operation Frost protect operation D h w operation Excessive temperature on primary circuit Faulty c h temperature probe NTC O res Faulty d h w temperature probe NTC Faulty primary circuit no water or absence of flow Lack of burner ignition no ignition signal from the full seqence ignition device Ignition gas pressure adjustment Lack of power supply or fauly electronic control p c b O Flashing lamp alone or simultaneously with an other lamp Flashing lamp alternate with another lamp Lamp Lamp OFF ON These conditions are normal only for a short time when the power supply is applied to the boiler If permanent they indicate a faulty p c b EM Dip switch selectors The function selectors 13 Fig 28 and Fig 31 are microswitches with which itis possible to select the vari ous boiler control function modes In Fig 31 the selectors are illustrated in th
42. tarting control p c b EX Function Fig 27 Inlet Information On the Electronic starting control p c b Function control C h temperature adjustment D h w temperature adjustment Function dip switches Max c h gas pressure adjustment Ignition gas pressure adjustment Boiler reset button control panel fascia 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 Outlet command Pump Three way diverter valve Full sequence ignition device Modulation operator Appliance operation light Operation service lamps Lock out signal lamp control panel fascia The fundamental function of the Electronic starting con trol p c b is that of controlling the boiler in relation to the external needs i e heating the dwelling or heating the water for d h w use and operating in order to keep the temperature of the hydraulic circuits constant This is obviously possible within the useful power and maximum working temperature limits foreseen Generally the Electronic starting control p c b receives inlet information coming from the boiler the sensors or from the outside knobs room thermostat etc pro cesses it and consequently acts with outlet commands on other components of the boiler Fig 27 EYEE Select
43. th a brush or non me tallic bristle brush In any case avoid any actions that can damage the pro tective varnish with which the exchanger has been cov ered Warning After cleaning or replacement as detailed above refer to section Combustion analysis check in the chapter Maintenance of the installation instructions manual 6 D h w heat exchanger MN Function The d h w heatexchangerAin Fig 13 allows the instan taneous transfer of heat from the primary hydraulic cir cuit to the water destined for d h w use ou Fig 13 The schematic structure is shown in Fig 14 A OU A V m Primary hydraulic circuit Domestic hot water circuit Fig 14 E Removal NN Warning isolate the boiler from the mains electricity supply before removing any covering or component 1 Remove the front and right hand side panels of the case 2 Empty the primary circuit and the d h w circuit of the boiler 3 Remove the motor of the three way diverter valve see section 8 3 4 Completely unscrew the two Allen key screws B Fig 15 which hold the exchanger to the brass groups 5 Move the exchanger towards the rear of the boiler and extract it Reassemble the d h w heat exchanger carrying out the removal operations in the reverse order Attention When reassembling the exchanger be sure to put the off center location securing pin indi cated in Fig 16 towards the le
44. the temperature of the primary circuit goes over 75 C the useful output is automatically reduced so that the primary circuit can not reach excessive temperatures The control sequences in function and in func tion are illustrated in detail in sections 9 11 and 9 12 EX Operation lights The Electronic starting control p c b is provided with three lamps L E D indicators 14 in Fig 28 that give optical information during the normal operation of the boiler or for service purpose O Normal operation Only the green lamp on the left is directly visible on the control panel fascia and it gives information during the normal operation of the boiler The other two lamps are normally switched off The following table gives the relationship between the visible lamp indication and its meaning Boiler in stand by condition function control in O position Anti freeze system active Boiler ON condition function control in or position ae Faulty boiler or irregular operation as Empty primary circuit Very fast pulses 4 per second _ No primary circuit flow Lack of burner ignition Excessive temperature in the primary circuit Dip switch 3 left in the OFF position Faulty temperature probe O Service operation With the boiler switched ON 24 or by moving and re setting to its original position any of the function se lectors 13 Fig 28 the Electronic starting control p c b goes into
45. upply network 3 Remove the gauge and close the pressure test point 6 4 Open the gas valve outlet pressure test point 8 in Fig 42 and connect the gauge 5 Remove the protection cap from the mechanical pressure adjustment components 6 Start the boiler at its maximum power Operate the boiler in d h w mode or ensure that the boiler is not range rated if the testis carried out in c h mode 7 Rotate the maximum gas pressure adjustment 4 in Fig 42 until you obtain the required pressure by rotating clockwise the pressure increases 8 Disconnect one of the two connectors 1 in Fig 42 or alternatively remove the service panel as explained in the section 2 3 ofthis manual and set the dip switch selector 1 see section 9 5 to the OFF position 9 Rotate the minimum gas pressure adjustment 2 in Fig 42 until you obtain the required pressure by rotating clockwise the pressure increases 10 Turn the boiler off and re connect the wire to the modulating operator or set the dip switch se lector 1 back to the ON position 11 Start the boiler and check again the maximum gas pressure setting 12 Turn the boiler off and disconnect the gauge Important after the gas pressure checks and any adjustment operations all ofthe test points must be sealed Modulating gas valve HEH Checks NN Warning isolate the boiler from the mains electricity supply before removing any covering or component Check the
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