Biasi RIVA PLUS M90S.24S User manual

Wall hung, fan flue,roomsealed gasboiler
SERVICEMANUAL
RIVAPLUS
Models: G.C.Appl.No.
M90D.24S47--970--15
M90D.28S47--970--16
M90D.24SR41--970--08
M90D.28SR41--970--09
Leave thismanualadjacent tothegas meter
Biasi U.K.Ltd
Unit31/33,PlanetaryRoad
IndustrialEstate,NeachellsLane
Willenhall,Wolverhampton WV13 3XB
Technicalhelpline:01902 304 400
Web site:www.biasi.co.uk

1
Tableofcontents
1Overall information2..................
1.1Overall View2.........................
1.2Hydraulicdiagram2....................
2Generalaccess andemptying
hydraulic circuits3....................
2.1Nomenclature3........................
2.2Bodypanels3.........................
2.3Controlpanel3........................
2.4Access tothesealedchamber4.........
2.5Emptyingtheprimarycircuit4...........
2.6Emptyingthed.h.w.circuit4............
3Diagrams5...........................
3.1WiringdiagramM90D.24SM90D.28S5...
3.2WiringdiagramM90D.24SR,M90D.28SR7
3.3Functionalflowdiagrams9..............
3.4Circuitvoltages10......................
4Faultfinding12........................
5Primaryheatexchanger14..............
5.1Characteristics14.......................
5.2Removal14............................
5.3Cleaning14............................
6D.h.w.heatexchanger15...............
6.1Function15.............................
6.2Removal15............................
7Pump16...............................
7.1Function16.............................
7.2Checks16.............................
7.3Removal16............................
8Three waydivertervalve17.............
8.1Function17.............................
8.2Checks17.............................
8.3Removalofthe electricactuator17........
8.4Removalofthedivertergroupand
itsinternalparts18......................
9Electronic controlp.c.b.19..............
9.1Function19.............................
9.2Selectionandadjustmentdevices19......
9.3Checkingthetemperature19.............
9.4Operationlights20......................
9.5Dip---switchselectors21.................
9.6Settingjumpers22......................
9.7Ignitiongaspressureadjustment22.......
9.8Maxc.h.poweradjustment22............
9.9Checks22.............................
9.10 Removalofthe electronic controlp.c.b22. .
9.11 Thermalcontrolinthe” ” mode24......
9.12 Thermalcontrolinthe” ” mode24......
10 Full sequenceignitiondevice25.........
10.1Function25.............................
10.2Checks25.............................
10.3Removal25............................
10.4Ignitionandcontrolsequence26..........
11 Modulating gasvalve27................
11.1Function27.............................
11.2Nomenclatureoftheparts27.............
11.3Adjustment27..........................
11.4Checks28.............................
11.5Removaloftheon---off operatorscoils28. .
11.6Removalofthegasvalve28..............
12 Primarycircuitflowswitch29...........
12.1Function29.............................
12.2Checks29.............................
12.3Removal29............................
13 Expansionvesseland
temperature-- pressuregauge30........
13.1Function30.............................
13.2Checks30.............................
13.3Removalofthe expansionvessel30.......
13.4Removalofthetemperature---pressure
gauge30...............................
14 D.h.w.flowswitch,filterandflowlimiter31
14.1Function31.............................
14.2Nomenclatureandlocationofparts31.....
14.3Checks31.............................
14.4Removaloftheflowswitchsensor31......
14.5Removaloftheflowswitchgroup
and d.h.w.circuitfilter31.................
14.6Flowlimiter32..........................
15 Temperatureprobe33..................
15.1Function33.............................
15.2Checks33.............................
15.3Removal33............................
16 By--pass valve34......................
16.1Function34.............................
16.2Removal34............................
17 Fan,venturideviceand
Airpressureswitch35..................
17.1Function35.............................
17.2Checks35.............................
17.3RemovaloftheFan36...................
17.4Inspectionandremovalofthe
venturidevice36........................
17.5RemovaloftheAirpressureswitch37.....
18 Ignitionand detectionelectrodes38.....
18.1Function38.............................
18.2Checks38.............................
18.3Removal38............................
19 Safetythermostat39...................
19.1Function39.............................
19.2Checks39.............................
19.3Removal39............................
20 Shortsparepartslist40................

2
1Overall information
1.1Overall View
Fan
Safety
thermostat
Main heat
exchanger
Burner
Ignition
electrodes
Gasvalve
Control
panel
Combustion
chamber
Automatic
air release
Pump
D.h.w.temp.
probe
D.h.w.
heatexchanger
Expansion
vessel
Detection
electrode
valve
D.h.w
flowswitch
Divertervalve
Airpressure
switch
Maincircuit
flowswitch
1.2Hydraulicdiagram
C
e
n
t
r
a
l
h
e
a
t
i
n
g
(
c
.
h
.
)
o
p
e
r
a
t
i
o
n
Domestichot water(d.h.w.)operation
C.h.
waterflow
C.h.
water return
D.h.w.
inlet
D.h.w
.
outle
t

3
2Generalaccess andemptying
hydraulic circuits
2.1Nomenclature
2
6
1
54
3
Fig.1
1Rightsidepanel
2Frontpanel
3Controlpanel lid
4Controlpanelcover
5Servicepanel
6Leftsidepanel
2.2Bodypanels
Warning:isolatetheboilerfromthemains
electricitysupplybeforeremovingany
coveringorcomponent.
Forthemostpartofthecheckandmaintenanceoper-
ationsitisnecessarytoremoveoneormorepanelsof
thecase.
Thesidepanelscanberemovedonlyaftertheremoval
ofthefrontpanel.
ToremovethefrontpanelremovescrewsA(Fig.2),lift
thepanelandremoveit.
A
Fig.2
ToremovethesidepanelsloosenthescrewsBandC
(Fig.3),bringthebaseofthepanelsawayfromthe
boilerandlift them,freeingthemfromthetophooks.
B
D
C
Fig.3--- bottomviewoftheboiler
2.3Controlpanel
Warning:isolatetheboilerfromthemains
electricitysupplybeforeremovingany
coveringorcomponent.
Togainaccess tothepartslocatedinsidethecontrol
panelproceedasfollows:
1Removethefrontpanelofthecase
2LoosenthescrewsBandC(Fig.3).
3RemovethescrewsD
4Movethelowerpartofthesidepanelsasindi-
catedinFig.4and pull thecontrolpanel.
Whencompletelypulledout,thepanelcanrotate
45°downwardstofacilitatetheserviceoper-
ationsontheinternalparts.

Generalaccess andemptyinghydraulic circuits
4
Fig.4
5RemovethescrewsEandremovetheservice
panel(Fig.5);
6Togainaccess tothe electronicregulationPCB
andthefull sequenceignitiondeviceremovethe
screwsFandremovethecontrolpanel lid
(Fig.5);
E
F
F
Fig.5
2.4Access tothesealedchamber
G
G
Fig.6
Togainaccess tothepartscontainedinthesealed
chamberitisnecessarytoremovethelidofthesealed
chamber.
Forthispurpose,removethefrontandsidepanelsof
thecase,removethescrewsGasindicatedinFig.6
andremovethelid.
2.5Emptyingtheprimarycircuit
1Closethec.h.circuitflowandreturncocksH.
(Fig.7).
H
H
J
Fig.7--- bottomviewoftheboiler
2Removethefrontandrightpanelsoftheboiler.
3OpenthedraintapI(Fig.8)untiltheboileriscom-
pletelyemptied.
4Closedraintapagainoncethe emptyinghas
beencompleted.
I
Fig.8
2.6Emptyingthed.h.w.circuit
5Closethed.c.w.inletcockJ(Fig.7);
6Openoneormorehotwatertapsuntiltheboiler
hasbeencompletelyemptied.

5
3Diagrams
3.1WiringdiagramM90D.24SM90D.28S
Ignition
electrodes
Flamedetection
electrode
bn=brown
bu=blue
bk=black
wh=white
rd=red
gy=grey
Externalcontrols
Electricsupply
Airpressure
switch
Timeswitch
123
t
bkbk
t
bk
bk bk
M
~
M
~
bk
bk
bk
bk
bk
bk
bk
terminalblock
terminalblock
gy bk
Pump
PrimarycircuitD.h.w.temperature
probeNTC
Three way
divertervalve
D.h.w.flow
switchflowswitch
C.h.temperature
probeNTC
Electronic
controlp.c.b.
Full sequence
ignitiondevice
gn=green
ye=yellow
rd
bu
whrd
bu
rd
bu
bn
bu
bn
bn
bu
bn
bu
bk bn bu
3 1 2
bk
gnye
bu
rd
bu bn
gnye gnye
gnye
gnye
gnye
gnye gnye gnye
gnye
bu bn
bn
bu
rd rd
wh
bu
rd
bu
rd
rd
gy
bn
bu
bu bu bn
bu
gy
rd
gnye
bn
bu
bk
rd
bk
wh
gn
NC
COM
NO
vt=violet
og=orange
gnye=green/yellow
bk
bu
bn
Wiringdiagramforboilerequipedwithfull sequenceignitiondevicetype:Bertelli&PartnersFM30
bk
bk
Modulating
gasvalve
gnye
gnye
bu
gnye
gy
bn
Safety
thermostatFan
M
~
ye
wh
gnye
vt
og
Safety
thermostat
Fan
M
~
bn
bu
gnye
bn bu
(alternativewiringcolours)

Diagrams
6
bn=brown
bu=blue
bk=black
wh=white
rd=red
gy=grey
gn=green
ye=yellow
vt=violet
og=orange
gnye=green/yellow
Ignition
electrodes
Flamedetection
electrode
Externalcontrols
Electricsupply
Airpressure
switch
Timeswitch
123
t
bkbk
t
bk
bk bk
M
~
M
~
bk
bk
bk
bk
bk
bk
bk
bk
bk
terminalblock
terminalblock
gy bk
Pump
Modulating
PrimarycircuitDHWtemperature
probeNTC
Three way
divertervalve
gasvalve
DHWflow
switchflowswitch
CHtemperature
probeNTC
Electronic
controlp.c.b.
Full sequence
ignitiondevice
gnye
gnye
bu
gnye
gyrd
bu
whrd
bu
rd
bu
bn
bu
bn
bn
bu
bn
bu
bk bn bu
3 1 2
rd
bu bn
bn
gnye
gnye gnye
gnye
gnye
gnye gnye gnye
gnye
bu bn
bn
bu
rd rd
wh
bu
rd
bu
rd
rd
gy
bn
bu
bu bu bn
bu
gy
rd
gnye
bn
bu
bk
rd
bk
wh
gn
NC
COM
NO
bk
bu
bn
bn
gnye
bu
Wiringdiagramforboilerequipedwithfull sequenceignitiondevicetype:Honeywell FPLD
Safety
thermostatFan
M
~
ye
wh
gnye
vt
og
Safety
thermostat
Fan
M
~
bn
bu
gnye
bn bu
(alternativewiringcolours)

Diagrams
7
3.2WiringdiagramM90D.24SR,M90D.28SR
Ignition
electrodes
Flamedetection
electrode
Safety
thermostat
ExternalcontrolsElectricsupplyFanAirpressure
switch
123
bk
t
bk
bk bk
M
~
bk
bk
bk
bk
M
~
bk
bk
terminalblockterminalblock
gy bk
Pump
Primarycircuit
flowswitch
C.h.temperature
probeNTC
Electronic
controlp.c.b.
Full sequence
ignitiondevice
rd
bu
bu
bn
bu
bn
bn
bu
bn
bu
bk
gnye
bu
rd
vt
bu
bn
bu bn
gnye gnye
gnye
gnye
gnye
gnye gnye gnye
gnye
bu bn
rd
bu
rd
rd
gy
bn
bu
bu bu bn
bu
gy
rd
gnye
ye
wh
gnye
vt
og
bn
bu
bk
NC
COM
NO
bn=brown
bu=blue
bk=black
wh=white
rd=red
gy=grey
gn=green
ye=yellow
vt=violet
og=orange
gnye=green/yellow
og
wh
ye
Wiringdiagramforboilerequipedwithfull sequenceignitiondevicetype:Bertelli&PartnersFM30
bk
bk
Modulating
gasvalve
gnye gnye
bu
gnye
gy
bn

Diagrams
8
bn=brown
bu=blue
bk=black
wh=white
rd=red
gy=grey
gn=green
ye=yellow
vt=violet
og=orange
gnye=green/yellow
Ignition
electrodes
Flamedetection
electrode
Safety
thermostat
ElectricsupplyFanAirpressure
switch
123
bk
t
bk
bk bk
M
~
bk
bk
bk
bk
bk
M
~
bk
bk
terminalblock
gy bk
Pump
Modulating
Primarycircuit
gasvalve
flowswitch
CHtemperature
probeNTC
Electronic
controlp.c.b.
Full sequence
ignitiondevice
gnye gnye
bu
gnye
gyrd
bu
bu
bn
bu
bn
bn
bu
bn
bu
rd
bu bn
bn
gnye
gnye gnye
gnye
gnye
gnye gnye gnye
gnye
bu bn
rd
bu
rd
rd
gy
bn
bu
bu bu bn
bu
gy
rd
gnye
ye
wh
gnye
vt
og
bn
bu
bk
NC
COM
NO
og
ye
bk
wh
vt
bu
bn
bn
gnye
bu
Wiringdiagramforboilerequipedwithfull sequenceignitiondevicetype:Honeywell FPLD

Diagrams
9
3.3Functionalflowdiagrams
PTCJ1--- 1
L
General layout
Transformer
N
Electronic
controlp.c.b.
(lowvoltagesection)
J1--- 2
J3--- 3
J3--- 5
J3--- 4
J3--- 2J3--- 1
J2--- 4J2--- 5
Three way
divertervalve
Pump
Full sequence
ignitiondevice
Fuse1,6AT
PTCJ1--- 1
L
Transformer
ACTIVECIRCUIT
INACTIVECIRCUIT
L--- LINEN--- NEUTRAL
N
Electronic
controlp.c.b.
(lowvoltagesection)
J1--- 2
J3--- 3
J3--- 5
J3--- 4
J3--- 2J3--- 1
J2--- 4J2--- 5
Three way
divertervalve
Pump
Full sequence
ignitiondevice
Fuse1,6AT
Heatrequestond.h.w.
PTCJ1--- 1
L
Transformer
N
Electronic
controlp.c.b.
(lowvoltagesection)
J1--- 2
J3--- 3
J3--- 5
J3--- 4
J3--- 2J3--- 1
J2--- 4J2--- 5
Three way
divertervalve
Pump
Full sequence
ignitiondevice
Fuse1,6AT
Heatrequestonc.h.

Diagrams
10
3.4Circuitvoltages
230~
Supplynetwork
230~
230~
0
Electricalvoltageswithburneron
duringc.h.ord.h.w.operation
onlyduringc.h.operation
onlyduringd.h.w.operation
230~
230~
230~
0
Pump
Full sequence
Ignitiondevice
3waydivertervalve
0 0
Electronic
controlp.c.b.
230~230~
Modulating
Gasvalve
Safety
thermostat
0
Fan
230~
230~
0
Electronic
controlp.c.b.
Air
pressure
switch
Diagramsforboilerequipedwithfull sequenceignitiondevicetype:Bertelli&Partners
FM30

Diagrams
11
230~
Supplynetwork
230~
230~
0
Electricalvoltageswithburneron
duringc.h.ord.h.w.operation
onlyduringc.h.operation
onlyduringd.h.w.operation
230~
230~
230~
0
Pump
Full sequence
Ignitiondevice
3waydivertervalve
0 0
Electronic
controlp.c.b.
230~230~
Modulating
Gasvalve
Safety
thermostat
0
Fan
230~
230~
0
Electronic
controlp.c.b.
Air
pressure
switch
Diagramsforboilerequipedwithfull sequenceignitiondevicetype:Honeywell FPLD

12
4Faultfinding
Componentstocheck
Sectionofthemanual! (noteref.inbrackets)
---
(1)
---
(2)
---
(3)
---
(4)
6 7.2 8.2 9.9 10.2 11.4 12.2 14.5 15.2 16 17.2 18.2 19.2---
(7)
---
(8)
--- ---
Lock---outsignal lampred
Defect #
Powersupplyline
Gas supplyline
Fluepipes
C.h.circuit
D.h.w.circuit
D.h.w.heatexchanger
Pump
Divertervalve
D.h.w.flowswitch
Fuse(regulationp.c.b.)
Regulationp.c.b.
Functionselectors(reg.p.c.b)
Full sequencedevice
Gasvalve(on---off operators)
Gasvalve(modulatingoperator)
Maincircuitflowswitch
D.h.w.filter
Maincircuit temp.probe
D.h.w.temp.probe
By--- pass valve
Fanandventuridevice
Airpressureswitch
Ignitionelectrode
Detectionelectrode
Safetythermostat
Injectors
Expansionvessel
Safetyvalve
Pressuregauge
Bypressingtheresetpush--- buttonthe boilerturnsonandoperatescorrectly.
J J
(6)
J J J
Bypressingtheresetpush--- buttonthe boilerstartstheignitioncycle. Theburnerdoesn’tlighton,theignition sparkscontinueandtheboilerlocks again.
J J J J
ON
Bypressingtheresetpush--- buttonthe boilerstartstheignitioncycle. Theburnerlightson,theignitionsparks continueandtheboilerlocksagain.
J J J J J
Theboilerdoesnotstarteitherinc/hor d.h.w.mode. All theoperationlightsOFF Fanstill.
J J J
Theburnerdoesn’tlighteitherinc.h.or d.h.w.mode. Fanturns.
J J J J
Theburnerdoesn’tlighteitherinc.h.or d.h.w.mode. Fandoesn’tturn.
J J J J J J J J
Theboilerdoesn’tcontrolthed.h.w. temperature. Turningthed.h.w.temp.adjustment knobhasn’teffectonthemodulationof theflame. Theboileroperatescorrectlyonc.h.
J J
OFF
Theboilerlightsforashortwhileonc.h. Normaloperationond.h.w.function.
J J

13
Componentstocheck
Sectionofthemanual! (noteref.inbrackets)
---------
(8)
---
(7)
19.218.217.21615.214.512.211.410.29.98.27.26---
(4)
---
(3)
---
(2)
---
(1)
Lock---outsignal lampred
Pressuregauge
Safetyvalve
Expansionvessel
Injectors
Safetythermostat
Detectionelectrode
Ignitionelectrode
Airpressureswitch
Fanandventuridevice
By--- pass valve
D.h.w.temp.probe
Maincircuit temp.probe
D.h.w.filter
Maincircuitflowswitch
Gasvalve(modulatingoperator)
Gasvalve(on---off operators)
Full sequencedevice
Functionselectors(reg.p.c.b)
Regulationp.c.b.
Fuse(regulationp.c.b.)
D.h.w.flowswitch
Divertervalve
Pump
D.h.w.heatexchanger
D.h.w.circuit
C.h.circuit
Fluepipes
Gas supplyline
Powersupplyline
Defect #
Theboilerdoesnotsupplyd.h.w.(cold waterfromthetap). Regularoperationinc/hmode even duringadrawingoff d.h.w.
J J J
Onc/hmodethetemperatureofthe maincircuitreaches75°Candthec/h systemdoesnotheat. Theboileroperatescorrectlyond.h.w. mode.
J J
IncorrectmodulationJ J J NoisybolierJ J Theboileroperatescorrectlybut the gaspressuretotheburner remainsat minimum.
J J
F
Poord.h.w.temperatureJ J J J J
(9)
OF
F
Lowd.h.w.flowrateJ J J
---
Waterleaksfromthesafetyvalveduring operationonc/h
J J J J
---
Waterleaksfromthesafetyvalvewhen theboilerisoff.
JJJ
Note Usefulinformationcanbeobtainedalsofromthe opticalindicationgivenbytheapplianceoper- ationlights(see section9.4). 1Checkfor230V~betweenline(L)andneutral(N)
Verifytheintegrityofsupplycable,plugandexternalfuses. Checkthepolarityoflineandneutralconnection
2Verifythesoundness ofthegas supplypipe,thepositionof
stopvalves.
Checkthegaspressureat theinlet testpointofthegasvalve (see sect.11.3)withtheboileratrestand duringoperationand compareitwiththevaluesgivenontheinstallationbooklet.
3Checkforsoundness andabsenceofobstructions.Verifythat
theflueterminaliscorrectlyinstalled(see clearances)anden- surethatexhaustgasisnotsucked backbytheboiler.
4Checkforsoundness ofthecircuitandverifyitscorrectfilling
(see alsoinstallationmanual).
5Ajammed by---pass couldcausetheover--- heatingofthemain
circuitandtheinterventionofthesafetythermostat.
6Checktheminimumgaspressureat theoutlet testpointofthe
gasvalve(see sect.11.3)andcompareitwiththevaluegiven ontheinstallationbooklet.
7Verifythecleanness ofinjectors. 8Checkthepressurizationofthe expansionvessel.Refertothe
installationmanualforpropervalues.
9d.h.w.pressuretoo highorflowratetoo high.Ifnecessaryin-
sertaflowratelimiter(14.6).

14
5Primaryheatexchanger
5.1Characteristics
TheprimaryheatexchangerAinFig.9hasthefunction
oftransferringheatproducedfromcombustionofthe
gastothewatercirculatinginit.
A
Fig.9
Thehydraulic circuitiscomposedof8ellipticalpipes
connectedinparallel(Fig.10).
Fig.10
5.2Removal
Warning:isolatetheboilerfromthemains
electricitysupplybeforeremovingany
coveringorcomponent.
1Emptytheprimarycircuitoftheboiler.
2Removethecasepanelsandthesealedchamber
lid(see section2).
3RemovethecombustionchamberlidBbyun-
screwingthescrewsC(Fig.11).
3bFormodelM90D.28SandM90D.28SRonly,re-
movethescrewDandtheplateE.
4RemovetheclipsFandthesafetythermostatG.
Itisnotnecessarytodisconnectitfromthewiring.
D
F
C
B
E
G
Fig.11
5UnscrewtheconnectionH(Fig.12),lift thepipe
Iandrotateitright thenmoveitdownwardsfree-
ingitfromtheheatexchangerconnection.
6Removethemotorofthethree waydivertervalve
(see section8.3).
7CompletelyunscrewtheconnectionJ.androtate
thepipeKdownwardsfreeingitfromtheheatex-
changerconnection.
8Removetheheatexchangerbyslidingitfor-
wards.
9Reassembletheboilercarryingout theremoval
operationsinreverseorder.Fit theclipsFwith
thearrowpointingupwardsasillustratedin
Fig.11.
H
I
J
K
Fig.12
5.3Cleaning
Iftherearedepositsofsootordirtbetweentheblades
oftheheatexchanger,cleanwithabrushornon---me-
tallicbristlebrush.
Inanycase,avoidanyactionsthatcandamagethepro-
tectivevarnishwithwhichthe exchangerhasbeencov-
ered.
Warning:Aftercleaningor replacementas
detailedaboverefertosectionCombustion
analysis checkinthechapterMaintenanceof
theinstallationinstructionsmanual.

15
6D.h.w.heatexchanger
6.1Function
Thed.h.wheatexchangerAinFig.13 allowstheinstan-
taneoustransferofheatfromtheprimaryhydraulic cir-
cuit tothewaterdestinedford.h.wuse.
A
Fig.13
Theschematicstructureis showninFig.14.
Primaryhydraulic circuit
D
o
m
e
s
t
i
c
h
o
t
w
a
t
e
r
c
i
r
c
u
i
t
Fig.14
6.2Removal
Warning:isolatetheboilerfromthemains
electricitysupplybeforeremovingany
coveringorcomponent.
1Removethefrontandrighthandsidepanelsof
thecase.
2Emptytheprimarycircuitandthed.h.wcircuitof
theboiler.
3Removethemotorofthethree waydivertervalve
(see section8.3).
4CompletelyunscrewthetwoAllenkeyscrewsB
(Fig.15)which holdthe exchangertothebrass
groups.
B
Fig.15
5Movethe exchangertowardstherearoftheboiler
andextractit.
Reassemblethed.h.w.heatexchangercarryingout the
removaloperationsinthereverseorder.
Attention.Whenreassemblingthe exchangerbe
suretoput theoff centerlocation/securingpinindi-
catedinFig.16 towardstheleftsideoftheboiler.
Fig.16

16
7Pump
7.1Function
ThepumpAinFig.17 hasthefunctionofmakingthe
waterinthemaincircuitcirculatethroughthemain heat
exchangerandthereforethroughthec.h.system(dur-
ingthec.h.function)orthroughthesecondaryheatex-
changer(duringthed.h.w.function).
A
Fig.17
7.2Checks
Warning:isolatetheboilerfromthemains
electricitysupplybeforeremovingany
coveringorcomponent.
nCheckthat thepumpisnotseizedandthat the
movementoftherotorisnotsubject tomechanicalim-
pediments.
Withtheboileroff,removethefrontpanel.Removethe
air releaseplugofthepumpandturntherotorwitha
screwdriver.
nCheckthe electricalcontinuity.
Withtheboileroff,removethefrontpaneland discon-
nect theconnectorB(Fig.18).
Measurethe electricalresistancebetweenthepump
supplyconnections.
Electricalresistanceofthewindings(atambient tem-
perature)mustbeabout230 W
nChecktheabsenceofstartingdefects.
Withtheboileroff removethefrontcasepanel.
Removetheair releaseplugfromthepump.Start the
boilerandwithascrewdriver,turntherotorinthedirec-
tionofthearrow.Ifthereisadefectinstarting,therotor
will begintoturn normallyonlystartingitmanually.
nCheckthat theimpellerisintegralwiththerotor.
Withtheboileroff removethefrontandrighthandside
casepanels,lowerthecontrolpanelandemptythepri-
marycircuit.
Removethepumphead byundoingthescrewswhich
holdit tothepump bodyandcheckthat theimpelleris
firmlyjoinedtotherotor.
7.3Removal
Warning:isolatetheboilerfromthemains
electricitysupplybeforeremovingany
coveringorcomponent.
1Removethefrontandrighthandsidecasepanels
2Emptytheprimarycircuitoftheboiler.
3Extractandlowerthecontrolpanel.
4Disconnect theconnectorB(Fig.18).
5UnscrewtheconnectionCandmovethepipeup-
wardsfreeingitfromtheoutletportofthepump.
6RemovetheforkDandthecapillarypipe.
7RemovethelockingplateEright(Fig.18).
E
B
C
D
Fig.18
8LoosentheconnectionF,removetheforkGand
thepipeH.
9UnscrewthetwoscrewsIthatholdthepumpon
theframe(Fig.19)andremovethepumptowards
thefrontoftheboiler.
I
F
G
H
Fig.19
Reassemblethepumpcarryingout theremovaloper-
ationsinthereverseorder.Whenreassemblingthe
pump,checkthecorrectlocationoftheO---ring gasket
intheinletportofthepumpthatsealstheconnection
betweenthepumpandthebrass group.

17
8Three waydivertervalve
8.1Function
ThedivertervalveA(Fig.20)hasthefunctionofmodify-
ingthehydraulic circuitoftheboilerbymeansofan
electric commandgivenbythe electronic controlp.c.b.
inordertosendthewaterthatexitstheprimaryheatex-
changertowardsthec.h.systemortowardsthed.h.w.
heatexchanger.
A
Fig.20
8.2Checks
nCheckthe electricalcontinuity
Fig.21 indicatestherelationship betweenthe electric
commandcomingfromthe electronic controlp.c.b.
andthepositionoftheactuatorB(brass spindle)when
theboileroperatesind.h.w.mode.
Fig.22 indicatestherelationship betweenthe electric
commandcomingfromthe electronic controlp.c.b.
andthepositionoftheactuatorB(brass spindle)when
theboileroperatesinc.h.mode.
Inbothfigurestherelationship betweenthepositionof
theactuatorandtheresistanceofthemotorwindings
(themotormustbedisconnectedfromthewiring)is
alsogiven.
B
bn=brown
bu=blue
bk=black
0V
230 V
SpindleB
notvisible
Opencircuit
9,4Kohm
bk bn bu
3
1
2
Fig.21 --- D.h.w.mode
B
bn=brown
bu=blue
bk=black
230 V
0V
SpindleB
visible
Opencircuit
9,4Kohm
bk bn bu
3
1
2
Fig.22 --- C.h.mode
8.3Removalofthe electricactuator
Warning:isolatetheboilerfromthemains
electricitysupplybeforeremovingany
coveringorcomponent.
1Removethefrontcasepanel.
2Disconnect theconnectorsC(Fig.23).
3RemovethefixingspringDandremovethe
actuatorE.
Reassembletheactuatorcarryingout there-
movaloperationsinthereverseorder.
Whenreassemblingtheactuator,refertoFig.21
ortothewiringdiagraminsection3.1forthecor-
rectwiringconnection.

Three waydivertervalve
18
D
CE
Fig.23
8.4Removalofthedivertergroupandits
internalparts
1Removethefrontand bothsidecasepanels.
2Emptytheprimarycircuitandthed.h.wcircuitof
theboiler.
3Removethe electricactuator(see section8.3).
4RemovethefixingspringF(Fig.24)andremove
theprimarycircuitflowswitchG.
5Disconnect thec.h.temperatureprobeH.
6UnscrewtheconnectorI,thec.h.flowconnector
andthed.h.w.outletconnector.
F
G
IH
Fig.24
7Removethed.h.w.heatexchanger(see section
6.2).
8RemovetheforkJandmoveawaythepipeK
(Fig.25).
9UnscrewthescrewLandremovethediverter
group.
J
K
L
Fig.25 Rearviewoftheboiler
10 Refertothe explodedviewinFig.26 toremove
theinternalpartsofthethree waydivertervalve.
Fig.26
11 Reassemblethedivertergroupcarryingout the
removaloperationsinthereverseorder.