424 S 428 S 424 RS Service manual
Contents
1. fig 15 The schematic structure is shown in fig 16 fig 17 4 Move the exchanger towards the rear side of the boiler and extract it Reassemble the d h w heatexchangercarrying outthe removal operations in the reverse order Attention Reassembling the exchanger be sure to A v A V putthe off center location securing pin indicated in fig 18 towards the left side of the boiler Primary hydraulic circuit Domestic hot water circuit fig 16 PEN Removal Nx Warning isolate the boiler from the mains electricity supply before removing any covering or component 1 Empty the primary circuit and the d h w circuit of the boiler fig 18 12 7 Pump LEE Function The pump A in fig 19 has the function of making the water in the 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 heatex changer during the d h w function Note the pump can be stopped by the intervention of the low limit water pressure switch fig 19 LEN Checks NN Warning isolate the boiler from the mains electricity supply before removing any covering or component Check that the pump2. High and low limit water pressure switches fig 52 EEJ Display circuit operation The following drawing fig 53 and list illustrate the position of each light and its function The colours are referred to the transparent windows of the control panel cover fig 53 1 Boiler on green It indicates the operation of the boiler When the boiler is switched on the indicator is continu ously lit except after the extinction of the burner during the c h operation In this condition the light flashes for a period of 3 min utes indicating the reignition delay state of the boiler This flashing indication is notaffected by the position of the function selector on the control circuit see sect 9 4 Switching the boiler on the light could remain switched off for a period not longer than 20 seconds due to the reset time of the control system 2 Heat request green 22 This light indicates the heat request signal from the electronic control circuit and it comes on when the water temperature d h w or c h circuit is lower than the requested on the control panel During d h w operation it coincides with the ignition of the burner During c h operation the light could be on and the burner could remain off due to the room thermostat and or time switch that don t call for heat 3 D h w request green This light comes on when the boi
3. fig 48 4 position the spindles as in fig 49 and mountthe panel cover After having installed the control panel make sure the central heating l and domestic hot water tempera ture adjustmentknobs can move freely halfa turn fig 49 Electronic control circuit EEN Thermal control in the s mode Switch in the function mode Y Green LED on See functioning with the function switch in the mode YES sec 9 10 NO Is primary circuit temperature higher than that selected YES NO Request for heat from room thermostat NO YES Circulator off Starts the circulator Ignition device off Supplies the ignition device fig 50 EXI Thermal control in the mode Switch in the function mode Circulator off m YES NO gt Ignition device off Y Circulator on Is domestic hot water outlet temperature lower than that required YES Supplies the ignition device Ignition device off fig 51 21 10 Display circuit EF Function The boileris equipped with a pcb thatdisplays some in formation about the operation of the appliance The electric signals that operate the display circuit are given directly by the electronic control circuit or by the water pressure switches Electronic control circuit
4. 18 EXI Function selectors The function selectors 6 fig 36 and fig 39 are microswitches with which itis possible to selectthe vari ous modes of functioning of the boiler In fig 39 the selectors are illustrated in the configur ation in which the p c b is setin the factory natural gas boiler E S Reignition delay M Gas pressure calibration N Gas change 7 No function ON 1 OFF 0 fig 39 O Selector2 Itselects the functioning ofthe boileron the basis ofthe type of gas used It allows the selection of the maximum supply current given to the modulator device To set correctly the selector follow the table of fig 40 Gas supply Position of selector Approx Max current trough the modu lator device Natural gas 120 mA L P G 165 mA fig 40 O Selector 3 It forces the functioning of the boiler in order to permit the optimal gas pressure atthe burner to be adjusted during the ignition phase The adjustment see section 9 5 is done by means of the potentiometer 8 marked ACC fig 36 Afterthe adjustmentoperations bring the selector back to the normal position ON adt ON 1 gt OFF 0 Normal gas pressure calibration fig 41 O Selector 4 It makes it possible to select the minimum time that must pass between two ignitions of the burner in c h function
5. 38 fig 90 disconnect the switch unscrew the nut that holds the switch to the bracket E and remove the thermostat reassemble the switch carrying out the oper ations in reverse order Safety thermostat 39 21 Shortspare parts list Key G C partno Description Q ty Manufac Manufacturer s reference turer part no MA e ncn WH o AX o mns wsnmetecwermonum 20021720 WI m a a a Air pressure switch mod 424 1 LN Natalini Type M 1 4 mbar Honeywell C6065 1 4 mbar Air pressure switch mod 428 1 LN Natalini Type M 1 6 mbar Honeywell C6065 1 6 mbar H ss mevew SOON CaS W x AA Emm Combustion chamber panes merum i eoms i fio fes ESOS 10 ese eTo CO AN 0 EE una Ens DE ESE 14 114 988 Pump BG1002 101 Myson CP53 WU TIER E00 699 Pump high head BG1901 104 Myson CP63 e E emeses EE EE 10 E 000 0 0 1e ear Ohw tow swich merses 10 E 0207 EE AN p euens Sioh menar pressen eb EM DLE EN lew iver presesh ste i e001 22 E a fs frer o O a e ENCON probe wan orar cram fi feer m ens IES 100 en 00000 ENE ES suanms E eus peemmseme 70 p E 207 m meme acetum E alternative 40 Short spare parts list 17962 0682 1 9811 12A3
6. 30 135 L FU Uo ccr ou Dueb oer roce pd 30 15 2 GREEKS ct CE ORDER 30 15 37 REMOVA I otto vaa t eo or ete e 31 16 By pass valve nnn 32 TG eT JPUDCUOTL eos cci boreali asta ele bot 32 16 2 JRemoval zc vetet ee 32 17 Water pressure switch and pump rele 33 LAA FUNCION a ert Gana s 33 17 2 CHECKS at epe ebrei fs 33 17 3 Removal of the pressure switch 33 17 4 Removal of the pump rel 33 18 Flue fan venturi air pressure switch 34 18 L Function ia Bande a dana 34 1 2 CGHECKS cda da npe bene peret haba 34 18 3 Removalofthefan 35 18 4 Removal of the air pressure switch 35 19 Ignition and detection electrodes 36 19 L EUNCUON sies jou Erg erben P xe Yes 36 19 2 Check oe e OD eR TENES 36 19 35 Removal isis a ERR EN 36 20 Safety thermostat ssseeeeee 37 20 1 Function taser ind apra doi 37 202 CheckS ice e tem eR N 37 20 3 1 Removal cei e eC tna 38 21 Shortspare parts list 40 1 Overall information IHE Overall View Automatic air release Fan valve Ne me Main heat E A ra i Expansion vessel exchanger IF j t R L y y Safe FERT i Air pressure Main circuit me e8 flow switch z EM E Full seq Control i ignition device 32a l n Gas inlet ty thermostat probe switch Ignition A 2 ui electrodes E A ae Combustion chamber Bur
7. 16 7 Unscrew the screw R that holds the d h w heat exchanger the bolt S that holds the valve to the frame fig 33 and remove the valve fig 33 The diverter mechanism is composed by two parts To reach them remove the hydraulic actuator as explained atthe step 3 ofthe partRemoval ofthe membrane ofthis chapter With a suitable spanner unscrew both plugs indicated in fig 34 and remove the parts ofthe diverter mechan ism fig 34 Reassemble the valve proceeding in the reverse order 9 Electronic control circuit EX Function Inlet Information d h w temperature probe main circuit temperature probe d h w pressure switch c h flow switch function switch d h w temperature reg c h temperature reg function selectors max c h power reg ignition gas pressure reg room thermostat Outlet command Flame ignition control device Gas modulator Pump fig 35 The fundamental function ofthe control circuit is that of controlling the boiler in relation to the external needs heating the room heating the water for d h w use op erating in orderto keep the temperature ofthe hydraulic circuits constant This is obviously possible within the useful power and maximum working temperature limits foreseen Generally the control circuit receives inlet information coming from the boiler the sensors orfr
8. ON 1 lt gt OFF 0 M 2 o 2 D w 3 2 fig 42 EXE Ignition gas pressure regulator By using the device 8 fig 36 marked ACC on the circuit board itis possible to adjust the gas pressure at the injectors in the ignition phase This pressure is maintained at the injectors untilignition occurs ionization signal To carry out the adjustment move the function selector n 3 downwards adjustment and use the adjustment device 8 ACC Bring the gas pressure atthe injectors to the value indi cated in the tables data for gas adjustment stated for each model in the second part of the manual ignition pressure By rotating the device clockwise the pressure in creases Check the regular ignition of the burner by turning the boiler on and off repeatedly After the adjustment operation move the selector up wards normal Lt a ON 1 lt gt OFF 0 Normal gas pressure calibration fig 43 EXI Max c h power regulator By using device 7 fig 36 marked RISC on the cir cuitboard you can limitthe maximum useful output de livered in the c h function This adjustment does notin fluence the maximum useful output delivered in d h w function By rotating the device clockwise the pressure in creases EXA Checks Check that the fuse is complete If the control circuit does not supply any device pump gas valve etc check tha
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11. main circuit and the d h w circuits of the boiler 32 3 remove the hydraulic actuator B fig 75 as ex plained in the section Diverter valve and d h w pressure switch of this manual remove the fork C and the pipe D D fig 75 rear view of the boiler 5 Unscrew the connector E and remove the by pass valve F fig 76 fig 76 6 reassemble the by pass valve as illustrated in fig 76 and proceeding in reverse order 17 Water pressure switch and pump relay HAN Function The boiler is equipped with two water pressure switches which are connected to the main c h water circuit They have two different operating points and by switching an electric circuit they indicate the water pressure by means of the display circuit fig 77 The lower limit pressure switch interrupts the power to the pump via the pump relay in the event that the sys tem pressure drops below 0 5 bar Display circuit High limit water pressure D switc gt y VF A Low limit t water pressure switch Pump rel fig 77 The high and low pressure switches can be identified by the color of the pastic plug situated on the end of each switch The table below gives further details Pressure switching point bar Re FEA Checks NN Warning isolate the boiler from the mains electricity supply before removing any covering or component 1 Switch offthe boile
12. of the air pressure switch Note that there are two different air pressure switches with different operating values for the 424 S 424 RS and 428 S boilers Refer to the short spare parts list for the correct selection of the switch NN Warning isolate the boiler from the mains electricity supply before removing any covering or component 1 Remove the front panel of the body and the lid of the sealed chamber 2 Disconnect the wires of the air pressure switch 3 Remove the two pipes from the air pressure switch 4 Unscrew the screw D two for the pressure switch of fig 80c which holds the air pressure switch to the frame fig 82 fig 82 Warning reassembling the air pressure switch refer to fig 80a b or c to connect correctly the wir ings and to fig 81 to connect the venturi device to the air pressure switch 35 19 Ignition and detection electrodes FEF 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 ignition sequence The third electrode is the detection electrode and it de tects the presence of the flame An Ignition 1 Detection fig 83 FUN Checks Check the position of the electrode edges NN Warning isolate the boiler from the mains electricity s
13. operator coil 1 Remove the front panel of the case and lower the control panel 2 Disconnectone of the two connectors 3 fig 58 ofthe modulating operator and measure the elec 25 Gas valve Ep fig 60 trical resistance of the coil Its electrical resistance value must be approx 125 O Check the modulating operator coil Remove the front panel of the case and lower the control panel Remove the full sequence ignition device see the section 11 3 of this manual Measure the electrical resistance between the leads of the on off operators as illustrated in fig 60 Upper on off operator approx 1 260 O Lower on off operator approx 30000 PEN Removal NN Warning isolate the boiler from the mains 26 electricity supply before removing any covering or component Remove the front panel of the case and lower the control panel Remove the full sequence ignition device see the section 11 3 of this manual Disconnect the modulating operator Unscrew the eightscrews indicated in fig 61 and remove the valve Reassemble the valve carrying out the removal operations in reverse order 13 Main circuit flow switch FER Function The main circuitflow switch A in fig 62 is a device that controls the speed of water that crosses the main heat exchanger
14. point Valve outlet gas pressure test point Gas pressure maximum adjuster Y Oo Ui A W N HG Gas pressure minimum adjuster PEN Adjustment fig 58 view from the left side of the boiler fig 59 Nx Warning isolate the boiler from the mains electricity supply before removing any covering or component 1 Remove the front panel ofthe case and lowerthe control panel as described in the section 2 2 2 open the gas pressure tap 4 atthe valve input connect a gauge and check the gas pressure of the supply network 3 close the gas pressure tap 4 4 open the gas pressure tap 5 atthe valve output and connecta pressure gauge 5 remove the protection cap from the mechanical pressure adjustment elements 6 disconnect one of the two connectors 3 of the modulating operator 7 start the boiler 8 rotate the minimum pressure adjuster 7 until you obtain the espected pressure by rotating clockwise the pressure increases 9 turn the boiler off and connect the wire to the modulating operator 10 startthe boiler 11 rotate the maximum pressure adjuster 6 until you obtain the espected pressure by rotating clockwise the pressure increases 12 tum the boiler off and disconnect the gauge Atthe end of the adjustment ensure to seal the gas test point EEN Checks Nx Warning isolate the boiler from the mains electricity supply before removing any covering or component Check the modulating
15. pressure switch in YES standby Y Starts fan lt lt Stops fan Memorizes shutdown Shutdown indicator light turns on A NO Fan pressure switch YES gt working Y Waitume Starts Wait time starts k Presence Ne of flame VE L NO Fan pressure switch YES working Waiting time YES i finished Starts ignition sparks Opens gas valve Ignition time starts Presence of flame NO YES Closes gas valve Stops fan YES Stops ignition sparks Memorizes shutdown Turns shutdown indicator light on Ignition time fin NS ished Stops ignition sparks Gas valve open NO Reset push button YES pressed Closes gas valve r YES Presence of flame NO gt YES Fan pressure switch NO working fig 57 24 12 Gas valve FERRE Function The gas valve controls the gas inflow to the boiler burner By means of an electric command given to the on off operators the passage ofthe gas through the valve can be opened or closed By means ofan electric command given to the modulat ing operator the pressure can be varied and therefore the gas flow rate to the burner modulation The modu lator device has mechanical organs which permit the adjustmentofthe minimum and maximum pressure ex iting the valve PREM Nomenclature of the parts On off operators Modulating operator Modulating operator s electric connectors Valve inlet gas pressure test
16. switch position L LNE N NEUTRAL ACTIVE CIRCUIT Heat request on d h w NACTE CIRCUIT a F2 1 6 A T PTC TRANSFORMER J4 1 L N a Eg gs m gt nv S TO THE CENTRAL z CIRCUIT S E LOW VOLTAGE rm 12V SECTION J4 4 HZ A e G o O e IGNITION B 9 DEVICE gt N A or gas valve J4 3 K2 RELAY A 4 5 13 17 3 8 CENTRAL HEATING PRESSURE SWITCH A Time switch 2 J3 3 E O OA N C Frostat jumper shown B Room thermostat jumper shown Function switch position Heat request on d h w F2 1 6 A T PTC TRANSFORMER N zy p gt 21V go TO THE CONTROL HOE CIRCUIT S 25 K1 RELAY LOW VOLTAGE D gt 12y SECTION J4 4 dnd A lo IGNITION B 2 nmn EE 8 ties K2 RELAY 4 5 13 7 J3 8 o NE PRESSURE pta SWITCH O A Time switch J 3 2 3 3 LO DO gt N C Frostat jumper shown B Room thermostat jumper shown Diagrams EX Control circuit voltages 230 V network C h D h w Room o J thermostat DE Se ce Z E ca er e e C h et AAA eC fiw s
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18. 0000000 fig 63 Mechanical function 1 Remove the front panel ofthe case and lowerthe control panel as described in the section 2 2 of this manual 2 Remove the fork C thatholds the main circuitflow switch B fig 64 3 Start and stop the boiler in c h operation time switch and external controls must call for heat and verify the position of the shaftD referring to fig 65 Boiler OFF Boiler ON fig 65 27 Main circuit flow switch EEEN Removal NN Warning isolate the boiler from the mains m fig 66 28 electricity supply before removing any covering or component Removal of the membrane Remove the front panel ofthe case lower the con trol panel and empty the main circuit Remove the fork E that holds the main circuit flow switch B fig 64 Unscrew the four screws F open the hydraulic operator and remove the membrane G fig 66 4 Assemble the part proceeding in reverse order Assembling the part ensure to place the concave side of the membrane towards the actuator plate H and the reference hole indicated in the seat fig 66 Removal of the switch 1 Switch off the boiler remove the front panel ofthe case lower the protection plate and lower the control panel 2 Remove the fork C that holds the switch placed on the valve and remove the switch fig 64 3 Open the box and disconnect the switch 4 Reassemble the switch proceeding in the reverse order 1
19. 4 9 Electronic control circuit 17 Oi inen 17 9 2 Selection and adjustment devices 17 9 3 Checking the temperature 17 9 4 Function selectors o ooooooo 18 9 5 Ignition gas pressure regulator 19 9 6 Max c h power regulator 19 9 7 GheCKS dinine eatae aa DA 19 9 8 Removal of the control circuit 19 9 9 Thermal control in the 88 mode 21 9 10 Thermal control in the mode 21 10 Display circuit sese 22 IQ L E lctionr zoom ez ere E oh 22 10 2 Display circuit operation 22 10 3 Remowal ee Een 22 11 Full sequence ignition device 23 TL FUNCION al nee 23 VAG gt OC lie cKs 5 8 cided een Probe ete e da 23 11 3 Removal Joli soa ec acea 23 11 4 Ignition sequence 24 12 Gas valVe iniciaran 25 TZT EUHCUOTI 5a es ni cd 25 12 2 Nomenclature of the parts 25 12 3 Adjustment lisaa 25 12 4 GheckS oce Gish ohana ease X RR 25 12 5 Removal aata ad Rex 26 13 Main circuit flow switch 27 T31 FUNCION iin reves co caet 27 13 2 Checka cinta Oka ete ete ht 27 13 3 RemoVval vrai nacre oranda een oe 28 14 D h w filter and flow limiter 29 141 General notes 0c ccc eee eee 29 14 2 Removal of the filter 29 14 3 Flow limiter ooooooo oo 29 15 Temperature probes
20. 4 D h w filter and flow limiter TE General notes The input port of the d h w circuit is provided wit a net filter and its function is to stop the passage of any impu rities through the circuit The d h w filter is located in the c h return group indi cated in fig 67 fig 67 IV Removal of the filter Nx Warning isolate the boiler from the mains electricity supply before removing any covering or component 1 Remove the front panel of the case the lower protection plate lower the control panel and empty the d h w circuit 2 Unscrew the plug A fig 68 and extract the filter fig 68 TEN Flow limiter 424 S bolers are provided in the factory with a flow li miter rated at 10 litres min If the flow rate of the d h w circuit on the 428 S boiler is too high it is also possible to limit it installing a flow limiter The following sizes are available Nominal flow rate litres min Colour To install the flow limiter operate as in the following se quence 1 Remove the d h w filter as explained in the sec tion 14 2 2 Unscrew the part B fig 69 and remove it from the body of the filter 3 Install the flow limiter C putting its smaller diam eter side towards the part B 4 Install the filter following the removing sequence in reverse order fig 69 29 15 Temperature probes FEF Function The temperature probe has the function of converting the temperature of the water of
21. Wall hung fan flue room sealed gas boiler Models 424 S 428 S 424 RS BIASI S p A 37135 Verona Italy Via Leopoldo Biasi 1 Stabilimento 33170 Pordenone Italy Via Pravolton 1 B GAIA Service manual Leave this manual adjacent to the gas meter sa Savio Table of contents 1 Overall information o 1 1 1 Overall VIEW il acra 1 1 2 Hydraulic diagram oo oo o o o o ooo 1 2 General access and emptying hydr circuits 2 2 1 Nomenclature ccc cece ee ees 2 2 2 Body panels cece eee 2 2 3 Access to the electric parts of the control panel 3 2 4 Access to the sealed chamber 3 2 5 Emptying the main circuit 3 2 6 Emptying the d h w circuit 3 3 Diagrams enn nn n nnn 4 3 1 Wiring diagram 00 eee eee 4 3 2 Functional flow diagrams 5 3 3 Control circuit voltages 7 4 Faultfinding eee 8 5 Main heatexchanger ee 11 5 1 Characteristics sida aaa 11 5 2 Removal ni rd 11 5 3 ACA Aad inte ELTe renes 11 6 D h w heatexchanger 12 6 1 FUNCION etre qr eoe d CR 12 6 2 ROMO luna E CR C IN 12 Dd Pump 5 vsies esten Dno ca dae 13 7 1 FUNCION eee APA 13 7 2 Checks castrar tad es 13 7 3 Removal ced e Ne AS 13 8 Diverter valve and d h w pressure switch 14 DI FUNCION aa teda ta 14 8 2 CheckKS eec Re cct 14 8 3 Removal cere CR ac e e DD T 1
22. ble Room thermostat 1 Ww bk plack L br w white i Pered Power line lt b gy grey N gly y yellow g y green yellow direct connection with the ignition and flame control device Pump relay Time switch Diagrams ERE Functional flow diagrams L LINE N NEUTRAL ACTIVE CIRCUIT INACTIVE CIRCUIT TO THE CONTROL CIRCUIT S LOW VOLTAGE SECTION HA gt N J3 8 General layout function switch position off E F2 1 6 AT O TRANSFORMER J4 1 L gt O O DO CAAAAAAAS O L7 NYC NC CNN 5x a GE i po 5h K1 RELAY J4 4 OF YY A e DO ol SR UN C O B O A GA j4 3 K2 RELAY i5 13 7 TIU O O C m O f CENTRAL HEATING PRESSURE SWITCH J3 2 J3 3 A Time switch N B Room thermostat jumper shown m E Ee C Frostat jumper shown Function switch position e Heat request on c h E F2 1 6 AT TRANSFORMER S1 FUNCTION SWITCH gt A Time switch B Room thermostat jumper shown C Frostat jumper shown COM OO TO THE CONTROL CIRCUIT S LOW VOLTAGE SECTION y N J3 8 CENTRAL HEATING PRESSURE SWITCH J3 2 J3 3 D O D gt N Diagrams Function
23. ctions in c h fig 37 the signal coming from the primary temperature probe is com pared to the signal given by the instrument panel through the adjustment made by the user knob JII The result of such a comparison operates the modula tion of the gas valve consequently changing the instan taneous useful output of the boiler D ON A UN uN 17 Electronic control circuit adjustment ON OFF adjustment modulating Central heating temperature fig 37 When the boiler functions in d h w fig 38 the signal coming from the d h w temperature probe is compared with the signal given by the instrument panel through the adjustment made by the user knob Seconda heat exchanger Gas L inlet r ga 75 C A ge we ee 165 32 1 EE 53 ze 9 n Domestic hot water temperature fig 38 Normally the result of the comparison between these two signals directly operates the adjustment elements ofthe gas valve adjusting the useful output generated in order to stabilize the temperature ofthe exiting water If during the functioning in d h w mode the tempera ture of the primary circuit goes over 759 the useful outputis automatically reduced so that the primary cir cuit cannot reach excessive temperatures The control sequences in function and in function are illustrated in detail in sections 9 9 and 9 10
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25. eck Itis possible to verify the general operation ofthe valve by measuring the voltage between the leads of the d h w pressure switch during the operation on c h and d h w NN Warning isolate the boiler from the mains electricity supply before removing any covering or component 1 Switch off the boiler and open the control panel 2 Connect a meter set for direct voltage measure ment to the points indicated in fig 23 3 Switch the boiler on position and verify the volt ages during c h and d h w by matching the read ings with the values indicated in the section 3 3 14 000000 00000000 fig 23 Check the mechanical function 1 Switch offthe boiler remove the front panel ofthe case the lower protection plate and lower the control panel 2 Remove the pressure switch as explained in the section 8 3 Removal of the switch 3 Open and close a d h w tap and verify the posi tion of the shaft B referring to fig 24 2 D h w tap OPEN 4 D h w tap CLOSED fig 24 EEN Removal NN Warning isolate the boiler from the mains electricity supply before removing any covering or component Removal of the membrane Removethe frontpanelofthe case lowerthe con trol panel and empty the d h w circuit 2 Remove the forks C and move away the pipes D fig 25 rear view of the boiler m Diverter valve and d h
26. ed fig 62 This device controls the regular functioning of the pump the presence of water in the primary circuitofthe boiler and the absence of obstructions ofthe main heat exchanger during the c h function as well as during the d h w function As a consequence of any one of these causes the main circuit flow switch cuts off an electric circuit by means of a microswitch B in fig 64 installed on it The main circuit flow switch is connected to the elec tronic control circuit and its intervention prevents or stops the burner ignition cycle but does not send the boiler in the lock state FEF Checks NN Warning isolate the boiler from the mains electricity supply before removing any covering or component Y General check Itis possible to verify the general operation ofthe switch by measuring the voltage between its leads during the operation on c h or d h w NN Warning isolate the boiler from the mains electricity supply before removing any covering or component 1 Switch off the boiler and open the control panel 2 Connect a meter set for alternating voltage 230V measurement to the points indicated in fig 63 3 Switch the boiler on position and verify the volt age by matching the readings with the values indicated in the section 3 3 oooo K1 K2 00000000 G 0000 000
27. ed on electronic ignition boilers with forced flue gas expulsion carries out the following fundamental func tions O does a sequence of operations ignition cycle which lead to the ignition ofthe gas atthe burner O checks the presence of the flame during the en tire period in which it is activated O supplies the fan and checks its functioning by means of the signal coming from the flue gas pressure switch The ignition device is supplied by the electronic control circuit when the ignition of the burner is requested The ignition device has a safety function and any in correct interventions or tampering can result in condi tions of dangerous functioning of the boiler The ignition device can lock the functioning of the boiler lock state and stop its functioning up to the resetting intervention The lock is signalled by the ignition ofthe lock lamp and the device can be reset only by using the reset push button placed on the instrument panel Some components which are connected to the device that can activate the lock state The causes of a lock state could be O theintervention ofthe safety thermostat primary hydraulic circuit a fault on gas feeding faulty ignition ignition electrode its wiring and connection faulty flame detection detection electrode its wir ing and connection gas injectors plugged faulty gas valve on off operators or not electri cally supplied O faulty ignition device othe
28. er cover Verify the soundness ofthe fitting between the main cir cuit pipe and the temperature probe C fig 88 Verify the integrity of the capillary which connects the probe to the switch If the capillary is broken the switch opens automatically Overheat temperature value Setthe temperature control knobs to their max position and run the boiler in d h w and c h Allow the boiler to 37 Safety thermostat reach its maximum operating temperature monitorthe temperature display on the control panel The boiler should operate and maintain a temperature below that of the safety thermostat and no overheat intervention should occur Itis not permissible to change the factory setting ofthe safety thermostat The safety thermostat must be re placed ifits operation temperature is too low and there fore constantly interrupts the correct functioning of the boiler and notallowing itto reach its maximum permiss ible operating temperatures Electrical function Remove the cover ofthe control panel as described in the section 2 3 Disconnectthe switch and check its electrical function Normally no intervention the contact must be closed electrical resistance zero O POE Removal 1 Removethe frontpanelofthe caseand the sealed chamber cover 2 remove the springs which hold the temperature probe and extract the probe from the sealed chamber 3 remove the cover of the control panel as de scribed in the section 2 3
29. he detection electrode is longer than the one of the ignition electrodes 20 Safety thermostat ES Function The safety thermostat A in fig 86 is a device that senses the temperature ofthe main circuit water which flows in the outlet pipe of the main heat exchanger Ifthe temperature control system ofthe boiler fails and the temperature of the main circuit reaches a danger ous temperature the safety thermostatopens the elec tric circuit which supply the full sequence ignition de vice Consequently the gas valve operators are no more activated and the gas flow to the burner is stopped ow gl 4 eq q d fig 86 The safety thermostat does not re set automati cally To reset itis necessary to remove the plug B and push the re setbutton with the help ofa tool on the instrument panel fig 87 fig 87 The safety thermostat has two parts O the temperature probe C which is fitted on the outlet pipe of the main heat exchanger fig 88 and the electric switch D which is fitted in the con trol panel fig 89 fig 88 fig 89 EB Checks NN Warning isolate the boiler from the mains electricity supply before removing any covering or component w Position of probe and integrity Remove the front panel of the case and the sealed chamb
30. 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 and lower the instrument panel Remove the air release plug of the pump and turn the rotor with a screwdriver Check the electrical completeness Remove the service panel disconnect the connector to the electronic control circuit see electrical diagram and measure the electrical resistance between the pump supply conductors fig 20 Electrical resistance of the windings at ambient tem perature on switch position 3 must be about 210 O Myson CP53 180 O Myson CP63 high head alternative 220 O Salmson MYE30 120 O Salmson MYL50 high head alternative Lessee Connector P P oooco fig 20 Check the absence of starting defects With the boiler off remove the front panel and lowerthe control panel for Myson pump unscrew the plug ofthe pump by hand the plug cannotbe removed Pull itand turn the rotor Start the boiler and verify if the motor runs for Salmson pump high head alternative remove the air release screw ofthe pump Startthe boiler and with a screwdriver have the rotor turn in the direction of the arrow Ifthere is a defectin starting the rotor will begin to turn normally only starting it manually Check that the impeller is integral with the rotor Remove the pump head loosing the screws which hold itto the pump bod
31. ler operates on d h w 4 Main circuit pressure yellow green red These lights indicate the pressure of the water in the main c h circuit Ifthe leftone yellow is on this means thatthe pressure is too low approx below 1 bar If the right one red comes on the water pressure is too high approx over 2 bar The central light green indicates the right pressure and the correct filling of the circuit 5 Main circuit temperature green yellow These lights indicate the water temperature in the main c h circuit All the lights are green with the exception of the right one that is yellow and indicates the highest tempera ture Only one ata time of these light is turned on The lights are turned on referring to the signal that comes from the central heating temperature probe Consequently the reading of the temperature can be altered by a faulty temperature probe TEN Removal NN Warning isolate the boiler from the mains electricity supply before removing any covering or component 1 Remove the cover of the control panel as de scribed in the section 2 3 of this manual 2 disconnect the connector A remove the two screws B fig 54 and remove the circuit board fig 54 3 assemble the circuit following the disassembly procedures in the reverse order 11 Full sequence ignition device ERN Function The ignition and flame control device type 4565DD us
32. model 428 S 4b Remove the front part of the flue gas hood by un screwing the four screws C fig 14b 5b Remove the cover of the combustion chamber fig 14b 6 Unscrew the automatic air valve connection nut D and remove the valve fig 14a 7 Separate the heat exchanger from the hydraulic circuit loosening the inlet and outlet pipe fittings For models 424 S 424 RS 8a movetheright pipe and free the right connection lower the right side of the exchanger and extract it from the front For model 428 S 8b Extractthe heat exchanger from the front 9 Unscrew the pipe E fig 14b from the heat ex changer 10 Assemble the heatexchanger carrying outthe re moval operations in reverse sequence EERE Cleaning If there are deposits of soot or dirt between the blades of the heat exchanger clean with a brush or non me tallic bristle brush In any case avoid any actions thatcan damage the pro tective varnish with which the exchanger has been cov ered 11 6 D h w heat exchanger 2 Remove the front panel of the case and lower the instrument panel SH Function 3 Completely unscrew the two Allen key screws B in fig 17 the right one is shown which hold the exchanger to the brass deviator groups The d h w heat exchanger A in fig 15 allows the in stantaneous transferral of heat from the primary hy draulic circuit to the water destined for d h w use
33. n its left and right side 2 fig 4 To remove the side panels loosen the screws B fig 5 bring the base of the panels far from the boiler and lift them freeing them from the side hooks of the frame To remove the lower protection plate completely un screw the screws B and remove the plate fig 5 fig 5 To gain access to the supply terminal block and to the parts located behind the control panel unscrew the screws C and lower the panel fig 6 PEN Access to the electric parts of the control panel w 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 remove the four screws D fig 7 and remove the cover pulling it towards the front fig 7 PY Access to the sealed chamber To gain access to the parts contained in the sealed chamber it is necessary to remove the cover of the sealed chamber Forthis purpose remove the front panel ofthe case and remove the screws E as indicated in fig 8 fig 8 FEN Emptying the main circuit 1 Close the c h circuit isolation valves F fig 9 General access and emptying hydraulic circuits fig 9 2 Open the draining tap G fig 10 until the boiler is completely emptied fig 10 To facilitate the downflow of water remove the front panel also
34. ner na h w Detection heat exchanger electrode rd Salaam Gas valve M JN 7 Pump Diverter ve _ Kg Q BiH li ern D h w temp 1 DE Ch probe D h w temp flow probe return y Frontview Rear view fig 1 FF Hydraulic diagram Central hetaing c h operation Domestic hot water d h w operation V j V F 2 SN NS Y p P D h w D h w C h C h h w water supply water return inlet outlet fig 2 2 General access and emptying hydraulic circuits PA Nomenclature fig 3 Right side panel Front panel Lower protection plate Control panel Case lid Left side panel PEF Body panels NN Warning isolate the boiler from the mains electricity supply before removing any covering or component oO U1 A WN H Forthe most part ofthe check and maintenance oper ations itis 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 the two screws A fig 4 and bring the base of the panel far from the boiler Lift the front panel freeing it from the hooks placed o
35. om the outside knobs room thermostat etc processes them and consequently acts with outlet commands on other components of the boiler fig 35 EF Selection and adjustment devices Onthe control circuitseveral selection adjustmentand protection devices are located fig 36 Several of these devices are directly accessible by the user function switch temperature adjustment poten tiometers etc others are accessible by removing the cover fig 36 function switch fuse F2 1 6 A K1 relay K2 relay ignition device control d h w temperature reg potentiometer function selectors c h maximum power adjustment RISC ignition gas pressure adjustment ACC c h temperature reg potentiometer EE Checking the temperature The control circuit makes it possible to separately ad just the c h water flow and d h w outlet temperature The temperature ofthe wateris converted into an elec tric signal by means of temperature probes The user setting the desired temperature with the knobs ofthe instrument panel operates the variable el ements 5 and 9 in fig 36 of the control circuit If the power requested is lower by about 40 of the maximum useful output the control is done by igniting at the minimum power and turning off the burner on off function Ifthe power is higher the boiler will modu late down to 40 of its maximum power output When the boiler fun
36. pump relay is located under the display circuit To remove it 1 gain acces to the electric parts of the control panel See sect 2 3 2 remove the display circuit see sect 10 3 3 disconnect the wirings and remove the relay 33 18 Flue fan venturi air pressure Switch FER Function The boilerhas a fan whose function is thatofforcing the expulsion ofthe products of combustion The fan is supplied by the full sequence ignition device atthe beginning of the ignition cycle Its correct functioning is controlled by means of a sys tem of a built in venturi device and an air pressure switch HEJ Checks Check of the fan NN Warning isolate the boiler from the mains electricity supply before removing any covering or component Remove the front panel of the body and the lid of the sealed chamber Disconnectthe connectors A fig 79 and measure the electrical resistance of the motor that has to be about 47 O 34 Check of the air pressure switch operation Nx Warning isolate the boiler from the mains electricity supply before removing any covering or component 1 Remove the front panel of the body and the lid of the sealed chamber 2 Disconnect the wires and check the electrical re sistance between its connections Between COM and NO the contact must be open Between COM and NC the contact must be closed electrical resistance zero Refer to the fig 80a b orc in accordance with the type of air p
37. r Remove the front panel ofthe case lower the control panel and empty the main circuit If you need to verify the operating point of the switches connect a suitable water pressure gauge to a test point of the circuit near the boiler 2 disconnect the connectors to the pressure switches and measure the electrical resistance between the connections fig 78 When the circuit is empty the contact between the connection COM and the connection NC must be closed the contact between COM and NO must be open fig 78 3 Gradually fill the circuit The lower limit pressure switch brown plug must switch ata pressure of about 0 5 bar Verify that the contact between COM and NC is open and between COM and NO is closed 4 To check the high limit pressure switch red plug further increase the pressure ofthe circuit ltmust switch ata pressure of about 2 bar Verify the con tacts as explained above After this test remember to decrease the water pressure to an adequate value Removal of the pressure switch 1 Empty the main circuit of the boiler 2 remove the front panel of the body the right side panel and lower the control panel 3 disconnect the wirings from the pressure switch and unscrew it 4 Reassemble the switch carrying out the removal operations in the reverse order Reassembling the pressure switch refer to the diagram of the section 3 1 to connect correctly the wirings Removal of the pump relay The
38. r components like the flue gas pressure switch can temporarily stop the ignition of the burner but allow its ignition when the cause of the intervention has stopped fig 57 shows the sequence of the operations that are carried out at the starting of every ignition cycle and during normal functioning HEN Checks M Shutdown sequence Start the boiler until the burner is ignited OO O 1 While the burner is on turn the gas supply off The de vice should carry outa complete ignition cycle and then shutdown When turning the boiler on and off with the function switch the device should notreset itself and the burner should not turn on HEN Removal Nx Warning isolate the boiler from the mains electricity supply before removing any covering or component 1 Remove the front panel of the case and lower the control panel see sect 2 2 2 unscrew the screw A and remove the protection cover B disconnect the flame detection cable C and the ignition cable D fig 55 fig 55 view from the left side of the boiler 3 remove the cable clamp and disconnect the two wires 4 remove the ignition device by moving it from to wards left fig 56 mey fig 56 23 Full sequence ignition device FER ignition sequence Supply from the electronic control circuit Shutdown YES NO K memorised Resets shutdown 3 NO Fan
39. remove the sealed chamber cover and loosen the nut H fig 10 of the automatic air bleed valve Tight it again once the emptying has been completed PUN Emptying the d h w circuit 1 Close the d h w circuit cut off valve fig 11 2 Open one or more hot water taps of the plant until the boiler has been completely emptied 3 Diagrams EF Wiring diagram Fan Airpressure Water pressure Water pressure switch switch switch High limit Low limit red plug brown plug Ignition Flame detection Safety Resetpush Shutdown NC NO NC COM NO electrodes electrode thermostat button lamp NC ES 3 z b hw gy a a Q Bp fr COM NO COM f P rs o4 b Display circuit L L type 10 81 tee te B 8 Bois eH br ef b enr eH bk eq b 0 ei br Ignition and fl S control device K B o o K2 2 Control circuit al type 10 80 y E o 3 fer bk eT w MS el b M ot bk N N M e em M 9 9 amp f ay 1 Gas valve Domestic hot Central heating Domestic hot Circulator Central heating water NTC NT water pressure pressure switch switch Electric supply connection Frostat bk br brown E bub
40. ressure switch used These switches are interchangeable 3 Connect the black wire COM and the brown wire NC 4 Run the boiler the fan must run and check the the electric resistance between COM and NO Between COM and NO the contact must be closed electrical resistance zero Remember that in this condition the boiler runs only for the ignition safety time and than it goes on Safety lock out The above described testhas to be carried out during this period NO NC COM fig 80a COM NO MSX PIS Pd row we b i a fig 80b COM NO NC 1 SEI H connection connection x 222 25 fig 80c EEN Removal of the fan NN Warning isolate the boiler from the mains electricity supply before removing any covering or component 1 Remove the front panel of the body and the lid of the sealed chamber 2 disconnect the connectors A and the earth con nection B fig 79 3 disconnect pipes which connect the venturi de vice to the air pressure switch 4 unscrew the screws C and extract it from the ex haust flue duct than move it towards the front of the boiler 5 remove the fan 6 assemble the fan carrying out the removal oper ations in reverse sequence Warning reassembling the fan refer to fig 81 to connect correctly the venturi device to the air pres sure switch upper pipe lower pipe or H connection fig 81 Flue fan venturi air pressure switch FEF Removal
41. t the fuse F2 is complete fig 44 The F2 fuse can be reached by removing the panel cover If the fuse is blown replace it with one that has the same characteristics after having identified the cause of the interruption Electronic control circuit oF M 1 6 A fig 44 CEN Removal of the control circuit NN Warning isolate the boiler from the mains electricity supply before removing any covering or component 1 Remove the cover of the control panel as de scribed in the section 2 3 of this manual 2 Delicately flex the hooks indicated infig 45 and disconnect the four connectors A fig 45 3 unscrew the three screws B and move away the bracket C fig 46 fig 46 4 unscrew the three screws D and remove the cir cuit fig 45 19 Electronic control circuit 5 assemble the control circuit following the disas sembly procedures in the reverse order Attention in order to facilitate the mounting of the cover 1 fig 47 20 position the knobs of the panel as illustrate in fig 47 dp tp d d O e B insert the spindles in the potentiometers E and F fig 48 and rotate them fully clockwise extract the spinldes and insert them with the flat side pointing in the direction shown in fig 48
42. the hydraulic circuit where itis installed into an electric signal resistance The relation between temperature and electrical resis tance is stated in fig 70 Sa GG A PA pae IE Aaa a RARE oe a REN 10 Sid eet EN on ERG ERE EU EP talca Se HH ERR ER MAA ERE EH ERE ERE RE N ceg E Eq p EE EE Ed E ER GRE Gi RR E ERE I ER 0 ERES ER 90005 sale ERE RET UNES Eur pps us p aaa Pere Tp TER RR ERE B AE ER ER GUT LU A 8 PARA A A E A 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 fig 70 In the boilers with mixed function c h d h w two temperature probes are assembled one on the output of the main heat exchanger main circuit temperature 30 A fig 71 and fig 72 one on its input before fig 71 and probe the pump d h w temperature probe B fig 73 c h c h d h w d h w flow return water inlet water outlet fig 71 EEN Checks 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 pipe near the tempera ture probe and check the electrical resistance accord ing to the graph in fig 70 Remember that a temperature probe failed in short cir cuitsends a signal to the con
43. trol circuitata temperature equivalent to 100c A disconnected or interrupted temperature probe sends a signal at a temperature equivalent 09 thus the burner will always be on maxi mum power Temperature probes EEN Removal Nx Warning isolate the boiler from the mains electricity supply before removing any covering or component To remove the main circuit orthe d h w tempera ture probes follow the same sequence Refer to fig 72 for the main circuit temperature probe to fig 73 forthe d h w temperature probe 1 Remove the front panel of the case and lower the instrument panel 2 empty the main circuit of the boiler 3 remove the electric connector of the temperature probe and unscrew it 4 assemble the temperature probe carrying outthe removal operations in reverse order fig 73 31 16 By pass valve HAH Function The by pass valve is located between the c h water flow and return A in fig 74 and its function is that of guaranteeing a minimum flow across the main heat ex changer also if the circulation across the c h system is completely closed fig 74 EN Removal Nx Warning isolate the boiler from the mains electricity supply before removing any covering or component 1 Remove the front panel of the case and lower the control panel 2 empty the
44. upply before removing any covering or component Remove the front panel of the body the sealed chamber cover and the combustion chamber panel Check for the correct distance between the metallic edges of the ignition electrodes and refer it to the fig 84 4mm aL Li a fig 84 36 Check the integrity of the detection electrode and en sure that its metallic edge is correctly placed over the ramp of the burner Check the connection wires NN Warning isolate the boiler from the mains electricity supply before removing any covering or component Remove the front panel of the body the lid of the sealed chamber and the cover of the combustion chamber Check for the integrity of the insulation of wires which connect the electrodes to the ignition device FEE Removal 1 Remove the front panel of the body the sealed chamber lid and the combustion chamber panel 2 Remove the burner unscrewing the four screws placed at the right and left sides of the burner 3 Remove the grid unscrewing the two screws placed on the rear side of the burner 4 Unscrew the screws A fig 85 which hold the electrodes to the burner 5 Extract the electrodes from the burner 6 disconnect the electrode wires from the full se quence ignition device 7 Assemble the electrodes carrying outthe removal operation in reverse order In order to recognize the electrodes refer to fig 83 Note the metallic edge of t
45. w pressure switch Assembling the part ensure to place the concave side of the membrane towards the actuator plate fig 27 When fixing the actuator to the valve fit the refer ence shaft in the seat of the valve fig 28 fig 25 3 Loose the screws E and remove the hydraulic actuator F fig 26 fig 28 Removal of the switch 1 Switch offthe boiler remove the front panel of the case the lower protection plate and lower the control panel 2 Remove the fork K that holds the d h w pressure switch L placed on the right side of the valve and remove the switch fig 29 3 Open the box and disconnect the switch fig 26 4 CP the switch proceeding in the reverse order 4 Unscrew the six screws G open the hydraulic actuator and remove the membrane H fig 27 Removalofthe valve and the diverter mechanism 1 Switch offthe boiler remove the frontpanel ofthe case the lower protection plate and lower the control panel 2 Drain the d h w and the c h circuits 3 Completely loosen the connections to the hy 5 Assemble the part proceeding in reverse order draulic circuits indicated in fig 30 fig 27 15 Diverter valve and d h w pressure switch fig 30 4 fig 31 5 Remove the forks that hold the d h w pressure switch O and the main circuit flow switch P and separate the switches from the valve fig 32 6 Disconnect the temperature probe Q fig 32
46. witch e g si 4 CG Ty C o o o Ignition device o E O S o Circulator Lr HO Al E 6 E EEN E EX E EA A 2 y N27 D h w S 5 flow switch y o 5 o 5 e E e Main circuit u e temperature e probe D h w temperature eee EE probe a never zero short circuit never 12V open circuit Modulating operator Electronic control circuit ganen Fan evice o Overheat thermostat b tbo gy br Tr9 Shut down lamp bk L e and resetbutton Bi br Tr9 br Tro b r e p O Air pressure switch F ha re Electronic control circuit Electrical voltages in Volts during normal operation with burner on at maximum power urepe SA20 J9110q aly pue enunuoo S peds uon 1UBI AY uo 3461 3 useop JaUINQ SY 3D UOQIUBI SY sues JaJ1Oq eui uopng ysnd 3esai ayy Buissald Ag uo pad due 3n0x201 ulebe S5 20 J9 10q Q4 pue enunuoo sueds uO0qIubI ayy uo suf jouung ay 3D UOQIUBI SY sues Je oq eui uopnq ysnd jesai ayy Buissald Ag uo pad due 3n0x201 d ee el dis dn hm Apoou 102 sajelado pue uo suum Je log eui uopng ysnd jesa ayy Buissald Ag uo pa duue 3n0x201 WoO pa duue 3no3201 uo pad 3ubi ainssaid yN utei uo u 16 WUBI uo 13 109 Was ue4 apouu Wu p Jo Y D Ul Jeune PAS JOU SBOP Ja IOq eur WO pa duue 3nox201 uo uaa 1961 eunsseJd PNP UILEN uo u 16 quf uo 13 109 Was ue4 epouu Wu p Jo Y D Ul Jeune HAS JOU
47. y and check thatthe impeller is firmly jointed with the rotor Removal Nx Warning isolate the boiler from the mains electricity supply before removing any covering or component If the clearance to the right side of the boiler is re stricted the removal of the pump can be easily achieved by first removing the head by unscrewing the four Allen keys screws B in fig 21 the two on the upper side indicated 1 Empty the main circuit of the boiler 2 Remove the front panel ofthe case the right side panel and lower the control panel 3 Disconnect the connector C fig 21 4 Completely unscrew the connection nuts D and remove the pump 5 Before the reassembling carefully clean the sup port seat of the gasket 6 Reassemble the pump carrying out the removal operations in the reverse order fig 21 13 8 Diverter valve and d h w pressure switch EX Function The diverter valve A in fig 22 has the function of mod ifying the hydraulic circuit of the boiler by means ofan hydraulic command given by the opening of a d h w tap in order to send the water that exits the main heat exchanger towards the c h system or towards the d h w heat exchanger Moreover it operates the d h w pressure switch which acts on the electronic control circuit fig 22 EF Checks General ch
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