Biasi RIVA ADVANCE HE M110B.24SM/C User manual

Wall hung, fanflue, roomsealed, high efficiency gas boiler
Service manual
RIVA ADVANCE HE
Models G.C. Appl. No.
M110B.24SM/C 47---583---11
M110B.32SM/C 47---583---12
M110B.24SR/C 41---583---07
Leave this manual adjacent to the gas meter
Warning:
Service / repairs must be carried out, only by a qualified Gas Safety
Registered Engineer, who will be responsible for the current Regulations for
gas appliances.
Note:
After servicing, complete the relevant Service Interval Record section of the
Benchmark Checklist of the user and installation manual.

- 3 -
Table of conTenTs
1 OVERALL INFORMATION..........................4
1.1 Overall View .....................................4
1.2 Hydraulic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2 GENERAL ACCESS AND EMPTYING HYDRAULIC CIR-
CUITS ..........................................5
2.1 Nomenclature ....................................5
2.2 Body panels......................................5
2.3 Control panel .....................................5
2.4 Access to the sealed chamber .......................6
2.5 Emptying the primary circuit .........................6
2.6 Emptying the d.h.w. circuit...........................6
3 DIAGRAMS .....................................7
3.1 Wiring diagram M110B.24SM/... M110B.32SM/... .........7
3.2 Wiring diagram M110B.24SR/... ......................8
3.3 Circuit voltages ...................................9
4 FAULT FINDING.................................10
5 CONDENSING HEAT EXCHANGER .................12
5.1 Function........................................12
5.2 Removal .......................................12
5.3 Cleaning .......................................13
6 D.H.W. HEAT EXCHANGER .......................14
6.1 Function........................................14
6.2 Removal .......................................14
7 PUMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
7.1 Function........................................15
7.2 Checks.........................................15
7.3 Removal pump ..................................15
7.4 Removal electrical capacitor . . . . . . . . . . . . . . . . . . . . . . . . 16
8 THREE WAY DIVERTER VALVE ....................17
8.1 Function........................................17
8.2 Checks.........................................17
8.3 Removal of the electric actuator .....................17
8.4 Removal of the tree way diverter valve ................18
8.5 Removal of the diverter group .......................18
9 ELECTRONIC CONTROL/IGNITION P.C.B. ...........19
9.1 Function........................................19
9.2 Selection and adjustment devices....................19
9.3 Checking the temperature ..........................20
9.4 Operation lights ..................................21
9.5 Setting the boiler control function modes ..............21
9.6 Adjustment of maximum useful output in c.h. mode ......21
9.7 Reignition frequency setting ........................22
9.8 Combi / C.H. only mode setting......................22
9.9 Settingthed.h.w.owmeteroperationmode ...........23
9.10 Checks.........................................24
9.11 Removal of the electronic control p.c.b ................24
9.12 Thermal control in the mode.....................26
9.13 Thermal control in the mode.....................27
10 TRANSFORMER ................................28
10.1 Removal .......................................28
10.2 Check the transformer.............................28
11 GAS VALVE ....................................29
11.1 Function........................................29
11.2 Nomenclature of the parts ..........................29
11.3 Adjustment......................................29
11.4 Checks.........................................30
11.5 Removal of the gas valve ..........................30
12 PRIMARY CIRCUIT FLOW SWITCH .................32
12.1 Function........................................32
12.2 Checks.........................................32
12.3 Removal .......................................32
13 EXPANSION VESSEL AND TEMPERATURE-PRESSURE
GAUGE........................................33
13.1 Function........................................33
13.2 Checks.........................................33
13.3 Removal of the expansion vessel ....................33
13.4 Removal of the temperature-pressure gauge ...........33
14 D.H.W. FLOWMETER, FILTER AND FLOW LIMITER ...34
14.1 Function........................................34
14.2 Description and location of parts - (Figure 14.2) .........34
14.3 Removal of the sensor.............................34
14.4 Checks.........................................34
14.5 Removaloftheowswitchgroupandd.h.w.circuitlter ..34
14.6 Flow limiter .....................................35
15 TEMPERATURE PROBE..........................36
15.1 Function........................................36
15.2 Checks.........................................36
15.3 Removal of the c.h. Temperature probe ...............36
15.4 Removal of the d.h.w. Temperature probe..............36
16 BY-PASS VALVE ................................38
16.1 Function........................................38
16.2 Removal .......................................38
17 FAN AND AIR BOX ..............................39
17.1 Function........................................39
17.2 Removal of the Air box and the Fan ..................39
18 IGNITION AND DETECTION ELECTRODES, BURNER
AND SPARK GENERATOR ........................40
18.1 Function........................................40
18.2 Removal of the Ignition and detection electrodes . . . . . . . . 40
18.3 Removal of the burner.............................40
18.4 Removal of the front insulation panel .................41
18.5 Removal of the rear insulation.......................41
18.6 Removal of the spark generator .....................42
18.7 Checks.........................................42
19 SAFETY THERMOSTAT ..........................43
19.1 Function........................................43
19.2 Checks.........................................43
19.3 Removal .......................................43
20 FLUE TEMPERATURE PROBE NTC AND SAFETY THER-
MAL FUSE .....................................44
20.1 Function........................................44
20.2 Removal .......................................44
20.3 Checks.........................................44
21 CONDENSATE TRAP ............................45
21.1 Function........................................45
21.2 Check the cleanness of the trap .....................45
21.3 Removal .......................................45
22 SHORT SPARE PARTS LIST ......................46

- 4 -
OVERALL INFORMATION
1 OVERALL INFORMATION
1.1 Overall View
Fan
Safety
thermostat
Burner
Ignition
electrodes
Gasvalve
Control
panel
Automatic
airpurger
Pump
D.h.w. temp.
probeD.h.w.
heat exchanger
Expansion
vessel
Detection
electrode
valve
Condensing
Diverter valve
Main circuit
Flue temperature
heat exchanger
Condensate
trap
flow switch
C.h. temp.
probe
probeNTC
Airbox
Gasrestrictor
Transformer
Switch
D.h.w. Flow
Spark
Generator
Condensing heat
exchangerair
purgervalve
C.h. pressure
reliefvalve
Safety thermal
fuse
A
ir hose
Codensate
trap
Figure 1.1
1.2 Hydraulic diagram
Figure 1.2
Centralheating (c.h.) operationDomestichot water(d.h.w.)operation
C.h.
water flow
C.h.
water return D.h.w.
inlet
D.h.w.
outlet

- 5 -
GENERAL ACCESS AND EMPTYING HYDRAULIC CIRCUITS
2 GENERAL ACCESS AND EMPTYING HYDRAU-
LIC CIRCUITS
2.1 Nomenclature
Figure 2.1
6
1
2
3
4
5
1 Right side panel
2 Front panel
3 Control panel lid
4 Control panel cover
5 Service panel
6 Left side panel
2.2 Body panels
Warning: isolate the boiler from the mains electrici-
ty supply before removing any covering or compo-
nent.
For the most part of the check and maintenance operations 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(Figure 2.2), lift the
panel and remove it.
Figure 2.2
A
To remove the side panels loosen the screws Cand D(Figure
2.3), bring the base of the panels away from the boiler and lift
them, freeing them from the top hooks.
Figure 2.3
B
C
D
- Bottom view of the boiler
2.3 Control panel
Warning: isolate the boiler from the mains electrici-
ty supply before removing any covering or compo-
nent.
To gain access to the parts located inside the control panel pro-
ceed as follows:
1 Remove the front panel of the case
2 Loosen the screws C and D (Figure 2.3).
3 Remove the screws B.
4 Move the lower part of the side panels as indicated in Figure
2.4 and pull the control panel.
When completely pulled out, the panel can rotate 45° down-
wards to facilitate the service operations on the internal parts.
Figure 2.4

- 6 -
GENERAL ACCESS AND EMPTYING HYDRAULIC CIRCUITS
5 Remove the screws E and remove the service panel (Figure 2.5);
6 Remove the screws Fand remove the control panel lid (Fig-
ure 2.5).
Figure 2.5
E
F
F
2.4 Access to the sealed chamber
Figure 2.6
G
G
To gain access to the parts contained in the sealed chamber it is
necessary to remove the lid of the sealed chamber. For this pur-
pose, remove the front and side panels of the case, remove the
screws G as indicated in Figure 2.6 and remove the lid.
2.5 Emptying the primary circuit
1 Closethec.h.circuit ow and return cocks tted by the in-
staller.
2 Remove the front and right panels of the boiler.
3 Open the drain tap I(Figure 2.8 combi or Figure 2.9 only c.h.)
until the boiler is completely emptied.
4 To help the draining of the primary circuit loose the condens-
ing heat exchanger air purger valve H (Figure 2.7).
Figure 2.7
H
Attention: some water could remain in the condensing heat
exchanger.
5 Close drain tap once the emptying has been completed.
Figure 2.8
I
Figure 2.9
I
2.6 Emptying the d.h.w. circuit
Figure 2.10
J
1 Close the d.c.w. inlet cock J (Figure 2.10).
2 Open one or more hot water taps until the boiler has been
completely emptied.

- 7 -
DIAGRAMS
3 DIAGRAMS
3.1 Wiring diagram M110B.24SM/... M110B.32SM/...
Figure 3.1
Ignition
electrodes
Flamedetection
electrode
Externalcontrols
terminal block
Electric supply
terminal blockThreeway
diverter valve
Pump
Fan
Primarycircuit
flow switch
D.h.w. flow
switch
C.h. temperature
probeNTC
Gasvalve
Safety
thermostat
Flue
temperature
D.h.w. temperature
probeNTC
probeNTC
LD1LD2LD3
F1F2
F3
K1
K2
K3
K4
LD4
P6
T3
X1
X2
X3
X5
X6
X7
X10X11
X12
X13
X17
X23
X24
P3
X14
X15
SB1
X16
X22
X9
bu bn
bu
bn
bububnbn
123
LN
gnye bu bn
bn
bkbu
bn bu
gnye
bn bk bu
bk
gnye bk
gnye
bkbk bn bk bu bu bn
gnye
gnye
bu
bn
bu
1
4
5
bu bn
bn bu
whog
wh
gy
t
t
bk rd
rd
bk
bu
bu
bu bu
wh
bu
wh
bu
M
~
rdbk
bugy
wh
rd
gy
bu
wh
bk
t
bk
wh
wh
bk
bkwh
NO
COM
rd
rd
rd
rd
gy gy
gy
gy
Transformer
230V~ /24V~
Spark
Generator
Time switch
rd
gn
bk
bn =brown
bu =blue
bk =black
wh =white
rd =red
gy =grey
gn =green
ye =yellow
vt =violet
og =orange
gnye =green/yellow
rdwh =red/white
bn
whwh
Safety
thermalfuse
t
gy
gy
wh
M
~3
2
1
wh
OUT
GND
5V
rd
rd
bk
bu
bn

- 8 -
DIAGRAMS
3.2 Wiring diagram M110B.24SR/...
Figure 3.2
LD1LD2LD3
F1F2
F3
K1
K2
K3
K4
LD4
P6
T3
X1
X2
X3
X5
X6
X7
X10X11
X12
X13
X17
X23
X24
P3
X14
X15
SB1
X16
X22
X9
Ignition
electrodes
Flamedetection
electrode
Externalcontrols
terminal block
Electric supply
terminal block
Pump
Fan
Primarycircuit
flow switch
C.h. temperature
probeNTC
Gasvalve
Safety
thermostat
Flue
temperature
probeNTC
bu bn
bu
bn
bububnbn
123
LN
gnye bu bn
bn
bkbu
bn bu
gnye
bn bk bu
bk
gnye bk
gnye
bnbu bu bn
gnye
gnye
bu
bn
bu
1
4
5
bu bn
bn bu
whog
wh
gy
t
bu
bu
bu bu
M
~
rdbk
bugy
wh
rd
gy
bu
wh
bk
t
bk
wh
wh
bk
bkwh
NO
COM
rd
rd
rd
rd
gy gy
gy
gy
Transformer
230V~ /24V~
Spark
Generator
bn =brown
bu =blue
bk =black
wh =white
rd =red
gy =grey
gn =green
ye =yellow
vt =violet
og =orange
gnye =green/yellow
rdwh =red/white
bn
whwh
Safety
thermalfuse
t
gy
gy
wh

- 9 -
DIAGRAMS
3.3 Circuit voltages
Figure 3.3
Electrical voltageswithburneron
during c.h. or d.h.w. operation
only during c.h. operation
only during d.h.w. operation
230~
Safety
thermostat
0
Fan
0
Main circuit
LD1LD2LD3
F1F2
F3
K1
K2
K3
K4
LD4
P6
T3
X1
X2
X3
X5
X6
X7
X10X11
X12
X13
X17
X23
X24
P3
X14
X15
SB1
X16
X22
X9
Supply network
230~
Pump
230~0230~
0
3way
diverter valve
230~
Gasvalve
24~
Transformer
24=
230~
33...200Hz
0...32 Hz
D.h.w.
Flow switch
pressure switch

- 10 -
FAult Finding
Components to check
Sectionofthe manual
(noteref.inbrackets)
10 ---
(1)
---
(
NO TAG
)
---
(3)
21.1 ---
(4)
67.28.29.911.4 12.2 14.5 15.2 16 17 18.7 18.7 19.2 19.2 20.1 ---
(7)
--- ---
Lock--- outsignallampred
Defect


Transformer
Powersupplyline
Gassupplyline
Flue pipes
Condensate drainpipeand trap
C.h. circuit
D.h.w. circuit
D.h.w. heat exchanger
Pump
Divertervalve
D.h.w. flow switch
Fuses(Electronic p.c.b.)
Electronic p.c.b.
Boiler settings
Gasvalve
Main circuitflowswitch
D.h.w. filter
Main circuittemp. probe
D.h.w. temp.probe
By---passvalve
Fanair restrictor
Sparkgenerator
Ignition electrode
Detectionelectrode
Safety thermostat
Gasrestrictor
Flue temperatureprobe NTC
Expansionvessel
Safety valve
Pressure gauge
By pressing thereset push --- button
theboilerturns on andoperatescor-
rectly.
         
By pressing thereset push --- button
theboilerstartsthe ignition cycle.
Theburnerdoesn’tlight on andthe
boiler locksagain.
          
ON
By pressing thereset push --- button
theboilerstartsthe ignition cycle. Theburnerlightsonand theboiler
locksagain.
    
Theboilerdoesnot starteitherinc/h or d.h.w. mode. Allthe operationlightsOFF
Fanstill.
  
Theburnerdoesn’t lighteitherinc.h.
or d.h.w. mode. Fanturns.
   
Theburnerdoesn’t lighteitherinc.h.
or d.h.w. mode. Fandoesn’tturn.
    
Theboilerdoesn’t controlthe d.h.w. temperature. Turningthe d.h.w. temp.adjustment
knob hasn’t effect on themodulation
of theflame. Theboileroperatescorrectlyonc.h.
 
OFF
Theboilerlightsfor ashort whileon c.h. Normal operationond.h.w.function.
    
4 FAULT FINDING

- 11 -
FAult Finding
Components to check
Sectionofthe manual
(noteref.inbrackets)
-----
--
--
(7)
2.912.911.0218.718.7617115.24.112.215.419.92.72.86---
(4)
21.1---
(3)
---
(
NO TAG
)
---
(1)
10
Lock---out signal lamp red
Pressure gauge
Safety valve
Expansionvessel
Flue temperatureprobe NTC
Gasrestrictor
Safety thermostat
Detection electrode
Ignition electrode
Sparkgenerator
Fanair restrictor
By---passvalve
D.h.w. temp.probe
Main circuittemp. probe
D.h.w. filter
Main circuitflowswitch
Gasvalve
Boiler settings
Electronic p.c.b.
Fuses(Electronic p.c.b.)
D.h.w. flow switch
Diverter valve
Pump
D.h.w. heat exchanger
D.h.w. circuit
C.h. circuit
Condensatedrain pipe andtrap
Flue pipes
Gassupply line
Powersupply line
Transformer
Defect
Theboilerdoesnot supply d.h.w. (cold waterfromthe tap). Regularoperation in c/hmodeeven
during adrawing offd.h.w.
  
On c/hmodethe temperatureofthe
main circuitreaches 90Cand thec/h
system does notheat.
Theboileroperatescorrectlyon
d.h.w. mode.
  
Incorrectmodulation   
Noisybolier     
Poor c.h. /d.h.w.temperature (9)    
F
Poor d.h.w. temperature. Regular operationinc/h mode.
  
(8)

OF
F
Lowd.h.w.flowrate   
---
Waterleaks from thesafetyvalve dur-
ingoperation on c/h
  
---
Waterleaks from thesafetyvalve
when theboilerisoff.
 
Note Useful informationcan be obtained also from the
opticalindicationgiven by theapplianceoper-
ationlights(seesection 9.4).
1Check for230V~ betweenline(L) andneutral (N)
Verify theintegrity of supply cable, plug andexternalfuses.
Checkthe polarity of line andneutral connection
2Check thegas supplypipeand isolationtap forgas tightness.
3Check forsoundness andabsence of obstructions.Verifythat
theflueterminal is correctly installed(seeclearances) anden-
sure that exhaustgas is notsuckedbackbythe boiler.
4Check forsoundness of thecircuit andverifyits correct filling
(see also installation manual).
5Ajammed by--- pass couldcause theover--- heatingofthe main
circuitand theinterventionofthe safety thermostat.
6Using theflueanalyzer,check theCO2valueofthe flue gases.
This readingisareferencevalue forthe gas valvesetting.
7Check thepressurization of theexpansion vessel.Refer to the
installation manual forpropervalues.
8d.h.w.pressure toohighorflowratetoo high.Ifnecessary in-
sert aflowratelimiter (14.6).
9The boiler doesn’treachthe nominalheatinput.



- 12 -
Condensing heat exChanger
5 CONDENSING HEAT EXCHANGER
5.1 Function
The Condensing heat exchanger Ain Figure 5.1 has the function
of transferring heat produced from combustion of the gas and
fromtheueexhaustedgastothewatercirculatinginit.
Figure 5.1
A
B
C
By reducing the combustion products temperature, the latent
heat of the vapour is transferred to the water circuit, allowing an
extra gain of useful heat.
The condensed vapour is then drained through the condensate
trap B and the draining pipe C.
5.2 Removal
Warning: isolate the boiler from the mains electricity
supply before removing any covering or component.
1 Disconnecttheuesystemfromtheboiler.
2 Remove the fan group (rubber pipe, gas pipe) following the
instructions from 1 to 6 in section "Removal of the Air box and
the Fan" page 39.
3 Disconnect the detection electrode connector D, the ignition
electrodes connector L and the earth wire M.
4 Disconnect the fan connector Iby pressing the plastic hook
placed on the side of the connector (Figure 5.2).
5 Unscrew the nuts N (Figure 5.2).
6 Remove the fan-burner group H.
7 Empty the primary circuit of the boiler.
8 Remove the clips E (Figure 5.2).
9 Loosen the connection Jand slightly move the pipe Kup-
wards, turn it towards left (Figure 5.2) and then move the pipe
downwards freeing it from the Condensing heat exchanger.
Figure 5.2
D
E
F
G
H
I
J
K
L
M
N
10 Loosen the connection Gand slightly move the pipe Fup-
wards, turn it towards left (Figure 5.2) and then move the pipe
downwards freeing it from the Condensing heat exchanger.
Figure 5.3
O
P
Q
R
11 Using pliers, remove the spring Omoving it downwards and
disconnect the rubber pipe P (Figure 5.3).
12 Unscrew the screws Q and remove the clamps (Figure 5.3).
13 Disconnect the two connectors Rby pressing the plastic hook
placed on the side of the connector (Figure 5.3).

- 13 -
Condensing heat exChanger
14 Remove the Condensing heat exchanger by levering it and
sliding it forwards.
15 Reassemble the Condensing heat exchanger carrying out
the removal operations in reverse order.
Ensure to tighten the nuts N - Figure 5.2 rmly.
5.3 Cleaning
If there are deposits of dirt on the coil of the Condensing heat
exchanger, clean with a bristle paintbrush and remove the dust
with a hoover.
Warning: After cleaning or replacement as detailed
above, if it deemed necessary to undertake a com-
bustion analysis as detailed in chapter 11.3 section
11.
Figure 5.4
S
Caution:
After any periodical servicing or disturbance the combustion
chamber silicon seal S Figure 5.4 must be fully inspected and
replaced at the discretion of the service engineer.
After any disturbance to the chamber door seal the appliance
must undergo a full analytical combustion performance check.

- 14 -
D.h.w. heat exchanger
6 D.H.W. HEAT EXCHANGER
6.1 Function
The d.h.w heat exchanger Ain Figure 6.1 and Figure 6.3 allows
the instantaneous transfer of heat from the primary hydraulic cir-
cuit to the water destined for d.h.w use.
Figure 6.1
A
The schematic structure is shown in Figure 6.2.
Figure 6.2
Primaryhydraulic circuit
Domestic hotwater circuit
6.2 Removal
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 pump Bin Figure 6.3 (see section "Removal
pump" page 15.
4 Remove the clip C and remove the primary circuit pressure
switch D by lifting it upwards. It is not necessary to disconnect
it from the wiring.
5 Remove the clip E and remove the electric actuator F by pull-
ing it. It is not necessary to disconnect it from the wiring.
Figure 6.3
B
C
D
E
F
A
6 Completely unscrew the Allen key screws G(Figure 6.4)
which hold the exchanger to the plastic groups.
Figure 6.4
A
G
7 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.
Warning: to lubricate the O-ring gaskets exclusively
use a silicone base grease compatible to be in con-
tact with foods and approved by the local water Au-
thorities.
Warning: When reassembling the exchanger be sure
to put the off center location/securing pin indicated
in Figure 6.5 towards the left side of the boiler.
Figure 6.5

- 15 -
PUMP
7 PUMP
7.1 Function
The pump Ain Figure 7.1 and Figure 7.4 has the function of
making the water in the main circuit circulate through the main
heat exchanger, the condensing heat exchanger and therefore
through the c.h. system (during the c.h. function) or through the
secondary heat exchanger (during the d.h.w. function).
Figure 7.1
A
7.2 Checks
Warning: isolate the boiler from the mains electricity
supply before removing any covering or component.
Check that the pump is not seized and that the movement of
the rotor is not subject to mechanical impediments.
With the boiler off, remove the front panel. Remove the air re-
lease plug of the pump and turn the rotor with a screwdriver.
Check the electrical continuity.
With the boiler off, remove the front panel and disconnect the
connector G (Figure 7.4).
Measure the electrical resistance between the pump supply con-
nections.
Electrical resistance of the windings (at ambient temperature)
mustbeabout213Ω(coil1)and480Ω(coil2)(Figure 7.2).
Check the absence of starting defects.
With the boiler off remove the front case panel.
Remove the air release plug from the pump. Start the boiler and
with a screwdriver, turn the rotor in the direction of the arrow.
If there is a defect in starting, the rotor will begin to turn normally
only starting it manually.
Check that the impeller is integral with the rotor.
With the boiler off remove the front and right hand side case pan-
els, lower the control panel and empty the primary circuit.
Remove the pump head by undoing the screws which hold it to the
pumpbodyandcheckthattheimpellerisrmlyjoinedtotherotor.
Figure 7.2
213 Ω
480Ω
Coil 1
Coil 2
7.3 Removal pump
Warning: isolate the boiler from the mains electricity
supply before removing any covering or component.
1 Remove the case panels and the sealed chamber lid (section
"Body panels" page 5).
2 Empty the primary circuit of the boiler.
3 Disconnect the connector G (Figure 7.4) following the indica-
tions given on the connector box.
4 Disconnect the earth connector E (Figure 7.4).
5 Loosen the connection D (Figure 7.3), and pull up and turn to
the left the pipe C.
6 Remove the locking plate H (Figure 7.5).

- 16 -
PUMP
Figure 7.3
B
C
D
Figure 7.4
A
E
F
G
Figure 7.5
H
7 Unscrew the two screws that hold the pump on the frame
and remove the pump.
Reassemble the pump carrying out the removal operations 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 between the pump and the return water
group.
7.4 Removal electrical capacitor
Warning: isolate the boiler from the mains electrici-
ty supply before removing any covering or compo-
nent.
1 Remove the front and right hand side case panels.
2 Disconnect the connector G (Figure 7.4) following the indica-
tions given on the connector box.
3 Remove the connector I of the cover box by levering with a
screwdriver in as shown in (Figure 7.6).
Figure 7.6
I
4 Remove the capacitor connection block J freeing it from the
hook K and pulling it as indicated by the arrow (Figure 7.7).
Figure 7.7
J K

- 17 -
Three way diverTer valve
8 THREE WAY DIVERTER VALVE
8.1 Function
The diverter valve A (Figure 8.1) has the function of modifying the
hydraulic circuit of the boiler by means of an electric command
given by the electronic control p.c.b. in order to send the water
that exits the primary heat exchanger towards the c.h. system or
towards the d.h.w. heat exchanger.
Figure 8.1
A
8.2 Checks
Warning: check the electrical continuity.
Figure 8.2 indicates the relationship between the electric com-
mand 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.
Figure 8.3 indicates the relationship between the electric com-
mand 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gurestherelationshipbetweenthepositionoftheactua-
tor and the resistance of the motor windings (the motor must be
disconnected from the wiring) is also given.
Figure 8.2 D.h.w. mode
bk =black
Open circui
t
9,4Kohm
bkbubn
bu =blue
bn =brown
230 V 0 V
B
Spindle visible
Figure 8.3 C.h. mode
bk =black
Open circui
t
9,4Kohm
bkbubn
bu =blue
bn =brown
0 V 230 V
B
Spindle not visible
8.3 Removal of the electric actuator
Warning: isolate the boiler from the mains electric-
ity supply before removing any covering or compo-
nent.
1 Remove the front case panel.
2 Disconnect the connectors C (Figure 8.4).
3 RemovethexingspringDandremovetheactuatorB.
Reassemble the actuator carrying out the removal operations
in the reverse order.
When reassembling the actuator, refer to Figure 8.2 or to the
wiring diagram in section "Checks" page 17 for the correct
wiring connection.

- 18 -
Three way diverTer valve
Figure 8.4
C
D
B
8.4 Removal of the tree way diverter valve
1 Remove the front and both side case panels.
2 Empty the primary circuit and the d.h.w circuit of the boiler.
3 Remove the electric actuator (section "Removal of the elec-
tric actuator" page 17).
4 RemovethexingspringE(Figure 8.5)
5 Remove the tree way diverter valve F by levering with a
screwdriver in as shown in Figure 8.5.
Figure 8.5
E
F
G
Reassemble the tree way diverter valve carrying out the removal
operations in the reverse order.
Warning: to lubricate the O-ring gaskets exclusively
use a silicone base grease compatible to be in con-
tact with foods and approved by the local water Au-
thorities.
Warning: When reassembling the tree way diverter
valve be sure that the tree way diverter is correctly
oriented by matching the reference G with the notch
of the water group Figure 8.5.
8.5 Removal of the diverter group
1 Remove the front and both side case panels.
2 Empty the primary circuit and the d.h.w circuit of the boiler.
3 Remove the electric actuator (section "Removal of the elec-
tric actuator" page 17).
4 RemovethexingspringH(Figure 8.6) and remove the pri-
mary circuit pressure switch I.
Figure 8.6
H
I
J
5 Disconnect d.h.w. temperature probe, respectively K (Figure
8.7).
Figure 8.7
K
6 Unscrew the connector I (Figure 8.6),thec.h.owconnector
and the d.h.w. outlet connector.
7 Remove the d.h.w. heat exchanger (section "Removal pump"
page 15).
8 Unscrew the screws and remove the diverter group.
9 Reassemble the diverter group carrying out the removal op-
erations in the reverse order.
Warning: to lubricate the O-ring gaskets exclusively
use a silicone base grease compatible to be in con-
tact with foods and approved by the local water Au-
thorities.

- 19 -
ElEctronic control/ignition p.c.b.
9 ELECTRONIC CONTROL/IGNITION P.C.B.
9.1 Function
Figure 9.1
From otherboilerdevices....
C.h. temperatureprobe NTC
D.h.w. temperatureprobe NTC
D.h.w. flow switch
Primarycircuit flow switch
Flue temperatureprobe NTC
Safety thermalfuse
Safety thermostat
Flamedetection electrode
Room thermostat (iffitted)
Time switch
On theElectroniccontrol/ignition
p.c.b.......
Function control
C.h. temperatureadjustment
D.h.w. temperatureadjustment
Boiler resetbutton
(control panelfascia)
InletInformation
Pump
Threeway diverter valve
Gasvalve
Fan
Ignition electrodes
Applianceoperationlights*
Lock--- outsignallamp*
*control panelfascia
Outlet command
The fundamental function of the Electronic control/ignition 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 cir-
cuits constant.
This is obviously possible within the useful power and maximum
working temperature limits foreseen.
Generally, the Electronic control/ignition p.c.b. receives inlet
information coming from the boiler (the sensors) or from the
outside (knobs, room thermostat, etc.), processes it and conse-
quently acts with outlet commands on other components of the
boiler (Figure 9.1).
The Electronic control/ignition p.c.b. is also a full sequence igni-
tion device and does a sequence of operations (ignition cycle)
which lead to the ignition of the gas at the burner.
Itchecksthe presence of the ame during theentire period in
which it is activated and supplies the fan regulating its speed.
The Electronic control/ignition p.c.b. has a safety function and
any incorrect interventions or tampering can result in conditions
of dangerous functioning of the boiler.
The Electronic control/ignition p.c.b. can lock the functioning of
the boiler (lock state) and stop its functioning up to the resetting
intervention. The lock is signalled by the lighting of the lock---out
signal lamp and the device can be reset only by using the boiler
reset button placed on the control panel fascia.
Some components which are connected to the device can acti-
vate the lock state. The causes of a lock state could be:
• The intervention of the safety thermostat (overheat of the pri-
mary circuit).
•Theinterventionoftheuetemperatureprobe(overheatofthe
combustion products).
• A fault on gas supply.
• Faulty ignition (faulty ignition electrodes, their wiring or connection).
• Faultyamedetection (faultydetectionelectrode,itswiringor
connection).
• Faulty condensate drainage.
• Faulty gas valve (faulty on-off operators or not electrically supplied).
• Faulty Electronic control/ignition p.c.b.
Othercomponentsliketheprimarycircuitowswitchcantempo-
rarily stop the ignition of the burner but allow its ignition when the
cause of the intervention has stopped.
Figure 9.23 and Figure 9.24 show the sequence of the opera-
tions that are carried out at the start of every ignition cycle and
during normal functioning.
9.2 Selection and adjustment devices
On the Electronic control/ignition p.c.b. several selection, adjust-
ment and protection devices are located. (Figure 9.2).
Some of these devices are directly accessible by the user (func-
tion control, temperature adjustment potentiometers etc.) others,
like the fuses, are accessible by removing the service panel.

- 20 -
ElEctronic control/ignition p.c.b.
Figure 9.2
1 2 3 4 5 6 7 8 9 10 11
121314151617181920
1 x7 - x16 connector - electric supply terminal block and exter-
nal controls terminal block.
2 Fuse F1, F2 3,15 A F
3 Fuse F3, 400 mA T
4 x15connector-amedetectionelectrode
5 x12 connector - pump and 3 way diverter valve
6 x17 connector - gas valve
7 x14 connector - external temperature probe (optional)
8 x9 connector - safety thermostat, ue temperature probe
NTC, c.h. temperature probe NTC
9 x11 connector - d.h.w. temperature probe
10 x10connector-d.h.w.owswitch
11 x13 connector - remote control (optional)
12 x2 connector - timer
13 Lock-out signal lamp
14 Boiler reset button
15 Function control / C.h. temperature adjustment
16 x22 connector - fan
17 x6 connector - spark generator
18 D.h.w. temperature adjustment
19 x5 - x24 connector - transformer
20 Appliance operation lights
9.3 Checking the temperature
The Electronic control/ignition p.c.b. makes it possible to sepa-
rately adjust the c.h. water ow temperature and d.h.w. outlet
temperature.
The temperature of the water is converted into an electric signal
by means of temperature probes.
The user, setting the desired temperature with the control panel
knobs operates the variable elements (15 and 18 in Figure 9.2)
of the electronic control p.c.b.
If the power requested is lower than 40% of the maximum power
output then control is achieved by switching 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 (Figure 9.3), the signal coming from the
c.h. temperature probe is compared to the signal given by the
control panel through the adjustment made by the user (knob
). The result of such a comparison operates the fan speed
thusregulatingthegasowrateandconsequentlychangingthe
useful output of the boiler.
Figure 9.3
When the boiler functions in d.h.w. (Figure 9.4), the signal com-
ing from the d.h.w. temperature probe is compared with the sig-
nal given by the control panel through the adjustment made by
the user (knob ).
Figure 9.4
90 °C
Normally, the result of the comparison between these two signals
directly operates the fan speed adjusting the useful output gen-