Biasi Advance Plus 25C ERP User manual

Service manual
Advance Plus ERP
Models G.C. Appl. No.
Advance Plus 25C ERP 47-583-35 COMBI BOILER
Advance Plus 30C ERP 47-583-36 COMBI BOILER
Advance Plus 35C ERP 47-583-37 COMBI BOILER
Advance Plus 25S ERP 41-583-28 SYSTEM BOILER
Advance Plus 30S ERP 41-583-29 SYSTEM BOILER
Leave this manual adjacent to the gas meter
Warning:
Service / repairs must be carried out, only by a qualified Gas Safe 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.
Wall hung, fanflue, roomsealed, high efficiency gas boiler

- 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 Case panels......................................5
2.3 Control panel .....................................6
2.4 Main electronic p.c.b. box ...........................6
2.5 Emptying the primary circuit .........................7
2.6 Emptying the D.H.W. circuit..........................7
3 DIAGRAMS .....................................8
3.1 Wiring diagram Advance Plus 25C ERP - Advance Plus
30C ERP - Advance Plus 35C ERP....................8
3.2 Wiring diagram Advance Plus 25S ERP - Advance Plus
30S ERP ........................................9
3.3 Circuit voltages ..................................10
4 FAULT FINDING.................................11
4.1 Display diagnostic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
4.2 Programming the maintenance period ................13
5 CONDENSING HEAT EXCHANGER.................14
5.1 Function........................................14
5.2 Removal .......................................14
5.3 Cleaning .......................................15
6 D.H.W. HEAT EXCHANGER .......................16
6.1 Function........................................16
6.2 Removal .......................................16
7 PUMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
7.1 Function........................................17
7.2 Removal pump ..................................17
8 THREE WAY DIVERTER VALVE ....................18
8.1 Function........................................18
8.2 Checks.........................................18
8.3 Removal of the electric actuator .....................18
8.4 Removal of the three way diverter valve ...............19
8.5 Removal of the diverter group .......................19
9 MAIN ELECTRONIC CONTROL/IGNITION P.C.B. ......20
9.1 Function........................................20
9.2 Selection and adjustment devices....................20
9.3 Checking the temperature ..........................21
9.4 Setting the boiler control function modes ..............22
9.5 Checks.........................................24
9.6 Removal of the electronic control p.c.b ................24
9.7 Thermal control in the mode.....................25
9.8 Thermal control in the mode .....................26
10 CONTROL PANEL ELECTRONIC P.C.B. .............27
10.1 Function........................................27
10.2 Normally information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
10.3 Info modality ....................................28
10.4 Function modes setting modality.....................28
10.5 Removal of the control panel electronic p.c.b . . . . . . . . . . . 28
11 GAS VALVE ....................................30
11.1 Function........................................30
11.2 Description of the parts . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
11.3 Adjustment......................................30
11.4 Checks.........................................32
11.5 Removal of the gas valve ..........................32
12 PRIMARY CIRCUIT PRESSURE SWITCH ............33
12.1 Function........................................33
12.2 Checks.........................................33
12.3 Removal .......................................33
13 EXPANSION VESSEL AND PRESSURE GAUGE ......34
13.1 Function........................................34
13.2 Checks.........................................34
13.3 Removal of the expansion vessel ....................34
13.4 Removal of the temperature-pressure gauge ...........35
14 D.H.W. FLOW SWITCH, FILTER AND FLOW LIMITER ..36
14.1 Function........................................36
14.2 Description and location of parts - (Figure 14.2) .........36
14.3 Removal of the sensor.............................36
14.4 Checks.........................................36
14.5 RemovaloftheowswitchgroupandD.H.W.circuitlter . 37
14.6 Flow limiter .....................................37
15 TEMPERATURE PROBE..........................38
15.1 Function........................................38
15.2 Checks.........................................38
15.3 Removal of the C.H. Temperature probe...............38
15.4 Removal of the D.H.W. Temperature probes............38
16 BY-PASS VALVE ................................40
16.1 Function........................................40
16.2 Removal .......................................40
17 FAN AND AIR BOX ..............................41
17.1 Function........................................41
17.2 Removal of the Air box and the Fan ..................41
18 IGNITION, DETECTION ELECTRODES AND BURNER .42
18.1 Function........................................42
18.2 Removal of the Ignition and detection electrodes . . . . . . . . 42
18.3 Removal of the burner.............................42
18.4 Removal of the front insulation panel .................43
18.5 Removal of the rear insulation.......................43
18.6 Checks.........................................43
19 SAFETY THERMOSTAT ..........................45
19.1 Function........................................45
19.2 Checks.........................................45
19.3 Removal .......................................45
20 FLUE TEMPERATURE PROBE NTC - FLUE THERMAL
FUSE AND SAFETY THERMAL FUSE ...............46
20.1 Function........................................46
20.2 Removal .......................................46
20.3 Checks.........................................46
21 CONDENSATE TRAP ............................48
21.1 Function........................................48
21.2 Check the cleanness of the trap .....................48
21.3 Removal .......................................48
22 SHORT SPARE PARTS LIST ......................49

- 4 -
OVERALL INFORMATION
1 OVERALL INFORMATION
1.1 Overall View
Figure 1.1
Gas restrictor
Condensing heat
exchanger air
purger valve
Condensing
heat exchanger
Flue temperature
probe NTC - flue
thermal fuse
Detection
electrode
C.H. temperature
probe NTC
Safety thermostat
Burner
Fan
Electronic controlbox
Expansion
vessel
Pipe silencer
Air/gas mixer)
Ighition
electrodes
Safety thermal fuse
Condensate
trap
C.H. pressure
relief valve
Automatic air
purger valve
D.H.W. heat
exchanger
Pump
Electric actuator
diverter valve
D.H.W. temperature probe
Three way
diverter valve
Main circuit
pressure switch
D.H.W. flow switch
Gas valve
1.2 Hydraulic diagram
Figure 1.2
Central heating (C.H.) operation Domestic hot water (D.H.W.) operation
D.H.W.
inlet
D.H.W.
outlet
C.H.
water flow
C.H.
water return

- 5 -
GENERAL ACCESS AND EMPTYING HYDRAULIC CIRCUITS
2 GENERAL ACCESS AND EMPTYING
HYDRAULIC CIRCUITS
2.1 Nomenclature
Figure 2.1
1
2
3
4
5
1 Right side panel
2 Front panel
3 Control panel
4 Main electronic p.c.b. box
5 Left side panel
2.2 Case 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 loosen screws "A" (Figure 2.2), lift the
panel and remove it.
Figure 2.2 - Bottom view of the boiler
A
B
B
Pull the lower part of the front panel and lift it upwards (Figure
2.3).
Figure 2.3
C
C
To remove the side panels loosen the screws "B" (Figure 2.2)
and "C" (Figure 2.3).
Pull the side panels towards the outside.
To Fit the case panels
Fit the side case panels.
Warning: Fit the front panel hooking it on the upper
side.
Push the spring towards the internal side of the boiler and simul-
taneously push the front case panel until it is completely hold in
place (Figure 2.4 step 1, 2).
Repeat the same operation on the opposite side of the front pan-
el (Figure 2.4 step 3, 4).
Ensurethatthefrontpaneledgeisclose-ttingtothesidepanels.
Lock in place the panel with the appropriate screws.
Figure 2.4

- 6 -
GENERAL ACCESS AND EMPTYING HYDRAULIC CIRCUITS
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 Unscrew the screw "D" (Figure 2.5).
3 Free the hooks indicated and rotate the lid towards left.
Figure 2.5
D
4 To access to the parts located behind the control panel to free
the hook "E" and turn it as shown in Figure 2.6.
Figure 2.6
E
2.4 Main electronic p.c.b. box
Warning: isolate the boiler from the mains electrici-
ty supply before removing any covering or compo-
nent.
To gain access to the parts located into main electronic p.c.b. box
proceed as follows:
1 Remove the front panel of the case.
Terminal block lid removal
2 To remove the terminal block lid "F" (Figure 2.7), free the front
hooks.
Figure 2.7
F
3 Slightly rotate the lid as indicated by the curved arrow and
free the rear hooks.
4 Remove the lid.
Main electronic p.c.b. lid removal
To get access to the main electronic p.c.b.:
5 Pull the box that contains the electronic p.c.b. and rotate it
(Figure 2.8).
Figure 2.8
6 Remove the terminal block lid "F" (Figure 2.7).
7 Free the hooks placed on the three sides indicated and rotate
the lid towards left (Figure 2.9).

- 7 -
GENERAL ACCESS AND EMPTYING HYDRAULIC CIRCUITS
Figure 2.9
2.5 Emptying the primary circuit
1 ClosetheC.H.circuitowandreturncocks"G"(Figure2.10).
Figure 2.10
G
H
2 Remove the front and right panels of the boiler.
3 Loosen the central heating drain cock "I" (Figure 2.11) until
the boiler is completely emptied.
Figure 2.11
OPEN
CLOSED
I
4 To make draining easier, lift the plug "J" of the automatic relief
valve in Figure 2.12.
Figure 2.12
J
2.6 Emptying the D.H.W. circuit
1 Close the D.H.W. inlet cock "H" (Figure 2.10).
2 Open one or more hot water taps until the boiler has been
completely emptied.

- 8 -
DIAGRAMS
3 DIAGRAMS
3.1 Wiring diagram Advance Plus 25C ERP - Advance Plus 30C ERP - Advance Plus 35C ERP
Figure 3.1
1
2
3
L
N
M
~1
2
3
1
3
4
M
~
Room thermostat
Frostat
terminal block
Electric supply
terminal block
Pump
diverter valve
evlavsaGyaweerhT
External temp.
Remote
Fan
Ignition
electrodes
Time switch (option)
probe
bu
bn
bu
bk
bn
bu
bn
bk
bu
bn
gnye
bu
bn
bk
bk
rd
rd
bu
gnye
bn
ye
bk
bk ye
gy
bk
bu
rd rd
bu
bk
bu
bn
gnye
gnye
bn
gnye
bu
bn
bu
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
terminal block
Fuse 2AF250VAC
5x20
wh
wh
wh
wh
gy
wh
wh
t
t
OUT
GND
5V
wh
bk
bk
bk
bk
bk
bk
rd
bu
bu
bu
bu
bk
bk
rd
wh
wh
rd
rd
bu
bu
rd
rd
rd
rd
Flamedetection
electrode
C.h. temperature
probeNTC
flow
D.h.w. outlet
probeNTC
temperature
D.h.w. flow
switch
pressure switch
Primarycircuit
Safety
thermostat
bn
bu
bu
bk
bk
rd
bu
bu
rd
rd
bu
tSafety
wh
bk
thermalfuse
Flue
bk
bk
Flue temp.
probeNTC
thermalfuse
tt
4
3
2
1
bu
bu

- 9 -
DIAGRAMS
3.2 Wiring diagram Advance Plus 25S ERP - Advance Plus 30S ERP
Figure 3.2
bk
bk
pressure switch
Primarycircuit
bk
bk
1
2
3
L
N
1
3
4
M
~
Room thermostat
Frostat
terminal block
Electric supply
terminal block
Pump
Gasvalve
External temp.
Remote
Fan
Ignition
electrodes
Time switch (option)
probe
bu
bn
bu
bn
bu
bn
gnye
bu
bn
bk
bk
rd
rd
bu
gnye
bn
ye
bk
bk ye
gy
bk
bu
rd rd
bu
bk
bu
bn
gnye
gnye
bn
bu
gnye
bu
bn
bu
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
terminal block
Fuse 2AF250VAC
5x20
wh
wh
wh
wh
gy
wh
wh
t
wh
bk
bk
bk
bk
bk
bk
rd
bu
bu
bu
bu
rd
Flamedetection
electrode
C.h. temperature
probeNTC
flow
Safety
thermostat
bu rd
bu
rd
bu
rd
tSafety
wh
bk
thermalfuse
Flue
bk
bk
Flue temp.
probeNTC
thermalfuse
tt
4
3
2
1
bu
bu

- 10 -
DIAGRAMS
3.3 Circuit voltages
Figure 3.3
Electrical voltages with burner on
during C.H. or D.H.W. operation
only during C.H. operation
only during D.H.W. operation
230~
230~
Safety
thermostat
1
Fan
0
Main circuitSupply network
230~
Pump
230~ 0
230~
0
3way
diverter valve
230~
Gasvalve
33...200Hz
0...32 Hz
D.H.W.
Flow switch
pressure switch

- 11 -
FAULT FINDING
4 FAULT FINDING
FAULT FINDING
Components to check
Section of the manual  (note ref. in brackets)
–
(1)
–
(2)
–
(3)
21.1 –
(4)
5 6 7.2 8.2 14.3 9.5 10 11.4 12.2 14.5 15.2 16 17 18.4 19.2 19.2 20.1 –
(7)
–––
Appliance lock–out (*)
Defect 
Power supply line
Gassupplyline
Flue pipes
Cond. drain pipe and trap
C.H. circuit
D.H.W. circuit
Condensing heat exchanger
D.H.W. heat exchanger
Pump
Diverter valve
D.H.W.owswitch
Fuses (Electronic p.c.b.)
Main electronic p.c.b.
Boiler settings
Control panel electr. p.c.b.
Gasvalve
Main circuit pressure switch
D.H.W.lter
Main circuit temp. probe
D.H.W. temp. probe
By–pass valve
Fan / air restrictor
Ignition electrode
Detection electrode
Safety thermostat
Gasrestrictor
Flue temp. probe NTC
Expansion vessel
Safety valve
Pressure gauge
External temp. probe
Display indicates ”Er”
Er 01 + A B D C
Er 02 + C A B
Er 03 + A
Er 04 + B A
Er 05 + A
Er 06 + A
Er 07 + A
Er 08 + A
Er 09 + A B
Er 10 + A B
A C B
Er 14 + A C B
Er 14 + A B Er 25 + A
Li 01 A
The letter in the cells indicates the possible fault cause. A.....Z indicates the most probably (A) to less probably (....Z)

- 12 -
FAULT FINDING
FAULT FINDING
Components to check
Section of the manual  (note ref. in brackets)
–
(1)
–
(2)
–
(3)
21.1 –
(4)
5 6 7.2 8.2 14.3 9.5 10 11.4 12.2 14.5 15.2 16 17 18.4 19.2 19.2 20.1 –
(7)
–––
Appliance lock–out (*)
Defect 
Power supply line
Gassupplyline
Flue pipes
Cond. drain pipe and trap
C.H. circuit
D.H.W. circuit
Condensing heat exchanger
D.H.W. heat exchanger
Pump
Diverter valve
D.H.W.owswitch
Fuses (Electronic p.c.b.)
Main electronic p.c.b.
Boiler settings
Control panel electr. p.c.b.
Gasvalve
Main circuit pressure switch
D.H.W.lter
Main circuit temp. probe
D.H.W. temp. probe
By–pass valve
Fan / air restrictor
Ignition electrode
Detection electrode
Safety thermostat
Gasrestrictor
Flue temp. probe NTC
Expansion vessel
Safety valve
Pressure gauge
External temp. probe
No ”Er” indication on display
The boiler does not start either in C.H. or D.H.W. mode. The control panel display OFF Fan still.
• • • •
The boiler does not supply D.H.W. (cold wa- ter from the tap). Regular operation in C.H. mode even during a drawing off D.H.W.
• • •
On C.H. mode the temperature of the main circuit reaches 90°C and the C.H. system does not heat. The boiler operates correctly on D.H.W. mode.
• • •
Incorrect modulation. • • • •
Noisy bolier. • • • • • •
Poor C.H. / D.H.W. temperature (9). • • • • •
Poor D.H.W. temperature. Regular opera- tion in C.H. mode. • • •
(8) •
LowD.H.W.owrate. • • •
–
Water leaks from the safety valve during op- eration on C.H. • • • • • •
–
Water leaks from the safety valve when the boiler is off. •••
* Lock out is indicated as “Er” on the display. Note
Useful information can be obtained also from the optical indication given by the appliance display (see section 4.1).
1 Check for 230V~ between line (L) and neutral (N). Verify the integrity of supply cable, plug and external fuses. Check the polarity of line and neutral connection.
2 Check the gas supply pipe and isolation tap for gas tightness. 3 Check for soundness and absence of obstructions. Verify
thattheueterminaliscorrectlyinstalled(seeclearances) and ensure that exhaust gas is not sucked back by the boiler.
4 Checkforsoundnessofthecircuitandverifyitscorrectlling
(see also installation manual).
5 A jammed by–pass could cause the over–heating of the
main circuit and the intervention of the safety thermostat.
6 Usingtheueanalyser,checktheCO2valueoftheue
gases.
This reading is a reference value for the gas valve setting. 7 Check the pressurization of the expansion vessel. Refer
to the installation manual for proper values.
8 D.H.W. pressure too high or ow rate too high. If
necessaryinsertaowratelimiter(14.6).
9 The boiler doesn’t reach the nominal heat input.

- 13 -
FAULT FINDING
4.1 Display diagnostic
Thedisplayindicationsprovidehelpinthediagnosisoffaultnd-
ing.
The control panel display gives other information for the user.
The following table gives fault code, error and the reson for the
fault.
Er 01 + RESET Lack of burner ignition on safety lockout
Er 02 + RESET Safety thermostat intervention lockout
Er 03 + RESET Generallockout
Er 04 + Faulty primary circuit (no water or absence
ofow)
Er 05 + Faulty fan control system
Er 06 + Faulty C.H. temperature probe NTC
Er 07 + Faulty D.H.W. temperature probe NTC
Er 08 + Faulty external temperature probe NTC
Er 09 + FaultyuetemperatureprobeNTC
Er 10 + RESET Flue probe intervention lockout
An 11 Flamedetectionerror(Anashing+number
errorashing
Er 12 + Faulty central heating temp. probe NTC (re-
turn)
Er 13 + DT delivery-return >40K
Er 14 + RESET Faulty pump (absence of water ow in the
main circuit) or primary temperature above
105 °C
Er 14 + Faulty primary circuit (no water or absence
ofow)(temperaturein-crease>2K/s)(the
boiler can’t restart for 10 minutes)
Er 19 + Domestic hot water inlet probe failure (if pre-
sent)
Er 25 + RESET Flame detection error
Er 69 Wiring error lockout
Li 01 Primary circuit temperature limit during
D.H.W. operation
Maintenance required
Thewrenchsymbolisashing(withoutshow-
ing any error)
4.2 Programming the maintenance period
1 To enter in the parameters setting mode press sequentially
the 3 keys "B - C - A" (Figure 4.1) and hold in for 10 second
until the display shows Figure 4.2.
Figure 4.1
A
B
C
Figure 4.2
2 Scroll the various parameters using keys "A" or "C" (Figure
4.1) until the LCD display indicates the letters Pr, alternating
with the code 28, indicating entry in “parameter 28" (Figure
4.3).
Figure 4.3
3 Press keys "B" and "A" (Figure 4.1) at the same time until
the LCD display indicates the value of parameter 28 (e.g.12
default value) Figure 4.4.
Figure 4.4
4 Pressing key "A" makes it possible to change the value of
parameter 28 from 0to 48 months. It is possible to set pa-
rameter 28 to 99 thereby disabling the maintenance request
(symbol will disappear from the display).
5 Bypressingkey"B"(Figure4.1)conrmationoftheinserted
value is obtained.
6 By pressing keys "B" and "C" (Figure 4.1) together, you will
exit without changing the value (return to parameter list Fig-
ure 4.3).
7 Press keys "B - C - A" (Figure 4.1) together for 10 seconds to
exit "programming mode".

- 14 -
CONDENSING HEAT EXCHANGER
5 CONDENSING HEAT EXCHANGER
5.1 Function
The Condensing heat exchanger "A" in Figure 5.1 has the func-
tion 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 "C" and the draining pipe "B".
5.2 Removal
Warning: isolate the boiler from the mains electrici-
ty supply before removing any covering or compo-
nent.
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 "17.2 Removal of the Air
box and the Fan" on page 41.
3 Disconnect the detection electrode connector "D", the ignition
electrodes connector "E" and the earth wire "F".
4 Disconnect the fan connector "G" by pressing the plastic
hook placed on the side of the connector (Figure 5.2).
5 Unscrew the connector "M" and remove the pipe "L" (Figure
5.2).
6 Unscrew the nuts "H" (Figure 5.2).
7 Remove the fan-burner group "I".
8 Empty the primary circuit of the boiler.
9 Remove the clips "J" (Figure 5.2).
10 Loosen the connection "L" and slightly move the pipe "K" up-
wards, turn it towards left (Figure 5.2) and then move the pipe
downwards freeing it from the Condensing heat exchanger.
11 Loosen the connection "O" and slightly move the pipe "P" up-
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
O
P
Figure 5.3
Q
R
12 Unscrew the screws "Q" and remove the clamps (Figure 5.3).
13 Disconnect the two connectors "R" by pressing the plastic
hook placed on the side of the connector (Figure 5.3).
14 Remove the Condensing heat exchanger by levering it and
sliding it forwards.

- 15 -
CONDENSING HEAT EXCHANGER
15 Reassemble the Condensing heat exchanger carrying out
the removal operations in reverse order.
Ensure to tighten the nuts "H" - 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, it is deemed necessary to undertake a com-
bustion analysis as detailed in chapter "11.3 Adjust-
ment" on page 30 section "11 GAS VALVE" on
page 30.
Figure 5.4
S
Caution:
After any periodical servicing or disturbance the combustion
chamber silicon seal "S" Figure 5.4 and the Air-gas duct gasket
(Figure 5.5) must be fully inspected and replaced at the discre-
tion of the service engineer.
After any disturbance to the chamber door seal the appliance
must undergo a full analytical combustion performance check.
Remove any limescale from the detection electrode
and replace it if worn.
Figure 5.5

- 16 -
D.H.W. HEAT EXCHANGER
6 D.H.W. HEAT EXCHANGER
6.1 Function
The D.H.W. heat exchanger "A" in Figure 6.1 and Figure 6.3 al-
lows the instantaneous transfer of heat from the primary hydrau-
lic circuit 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 electrici-
ty supply before removing any covering or compo-
nent.
1 Remove the panels of the case.
2 Empty the primary circuit and the D.H.W. circuit of the boiler.
3 Remove the control panel following the instructions from 4 in
section 2.3.
4 Remove main electronic p.c.b. box following the instructions
from 5 in section 2.4.
5 Completely unscrew the Allen key screws "B" in Figure 6.3
which hold the exchanger to the plastic groups.
Figure 6.3
B
A
B
6 Move the exchanger towards the rear of the boiler and extract
it to the left.
Reassemble the D.H.W. heat exchanger carrying out the remov-
al 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 indi-
cated in Figure 6.4 towards the left side of the boiler.
Figure 6.4

- 17 -
PUMP
7 PUMP
7.1 Function
The pump "A" in Figure 7.1 and Figure 7.2 has the function of
making the water in the main circuit circulate through the main
condensing heat exchanger and therefore through the C.H. sys-
tem (during the C.H. function) or through the secondary heat ex-
changer (during the D.H.W. function).
Figure 7.1
A
Warning: isolate the boiler from the mains electrici-
ty supply before removing any covering or compo-
nent.
Check that the pump is not seized and that the movement of
the rotor is not subject to mechanical impediments.
Switch the boiler on.
The boilers P.C.B. software has an automatic pump seizure han-
dling program built in.
There is no inspection plug and it's not necessary to operate
manually with screwdriver.
Check that the impeller is correctly connected to the rotor
shaft and that the rotor moves freely.
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.
7.2 Removal pump
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 Empty the primary circuit of the boiler.
3 Disconnect the connector "E" (Figure 7.2).
Figure 7.2
B
C
D
E
A
F
G
H I
4 Loosen the connection "C",and pull up and turn to the left the
pipe "D".
5 Remove the fork "H", loosen the connection "B" and remove
thepipe"G".
6 Remove the locking plate "I".
7 Unscrew the two screws "F" 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 plastic group.

- 18 -
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 com-
mand 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 before undertaking any resistance
tests) is also given.
Figure 8.2
bk =black
Open circuit
9,4Kohm
3
bnbubk
21
bu =blue
bn =brown
230 V 0 V
B
Spindle visible
D.H.W. mode
Figure 8.3
bk =black
Open circuit
9,4Kohm
3
bnbubk
21
bu =blue
bn =brown
0 V 230 V
B
Spindle not visible
C.H. mode
8.3 Removal of the electric actuator
Warning: isolate the boiler from the mains electrici-
ty 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E.
Reassemble the actuator carrying out the removal operations
in the reverse order.
When reassembling the actuator, refer to Figure 8.3 or to the
wiring diagram in section "3 Diagrams" on page 8 for the
correct wiring connection.
Warning: Please note the electric actuator is ener-
gized 240VAC even if the boiler is in a standby con-
dition.

- 19 -
THREE WAY DIVERTER VALVE
Figure 8.4
C
D
E
8.4 Removal of the three 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 (see "8.3 Removal of the elec-
tric actuator" on page 18).
4 Removethexingspring"F"(Figure8.5)
5 Removethethreewaydivertervalve"G"byleveringwitha
screwdriver in as shown in Figure 8.5.
Figure 8.5
F
G
H
Reassemble the three way diverter valve carrying out the remov-
al 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.
Attention. When reassembling the three way diverter valve
be sure that the three way diverter is correctly oriented
by matching the reference "H" 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 "8.3 Removal of the
electric actuator" on page 18).
4 Removethexingspring"I"(Figure8.6)andremovethepri-
mary circuit pressure switch "J".
Figure 8.6
I
J
5 Disconnect D.H.W. temperature probe "K".
Figure 8.7
K
L
M
6 Unscrewthe connector "L"(Figure 8.7), the C.H.ow con-
nector and the D.H.W. outlet connector.
7 Remove the D.H.W. heat exchanger (see "6.2 Removal" on
page 16).
8 Unscrew the screw "M" 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.

- 20 -
MAIN ELECTRONIC CONTROL/IGNITION P.C.B.
9 MAIN ELECTRONIC CONTROL/IGNITION
P.C.B.
9.1 Function
Figure 9.1
From otherboiler devices....
C.H. temperatureprobe NTC
D.H.W. temperatureprobe NTC
D.H.W. flow switch
Primarycircuit pressure switch
Flue temperatureprobe NTC
Safety thermostat
Flamedetection electrode
Room thermostat (iffitted)
Time switch (iffitted)
On theMain electronic control/ignition
p.c.b. ......
Function control
C.H. temperatureadjustment
D.H.W. temperatureadjustment
Boiler resetbutton
(printed circuit boardp.c.b.)
InletInformation
Pump
Threeway diverter valve
Gasvalve
Fan
Ignition electrodes
Displayindicates “Er”*
*control panelelectronicp.c.b.
Outlet command
The fundamental function of the Main 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 hy-
draulic circuits constant.
This is obviously possible within the useful power and maximum
working temperature limits foreseen.
Generally,theMain electronic control/ignition p.c.b. receives in-
let information coming from the boiler (the sensors) or from the
outside (printed circuit board p.c.b., room thermostat, etc.), pro-
cesses it and consequently acts with outlet commands on other
components of the boiler (Figure 9.1).
The Main electronic control/ignition p.c.b. is also a full sequence
ignition device and does a sequence of operations (ignition cy-
cle) 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 Main electronic control/ignition p.c.b. has a safety function
and any incorrect interventions or tampering can result in condi-
tions of dangerous functioning of the boiler.
The Main electronic control/ignition p.c.b. can lock the function-
ing of the boiler (lock state) and stop its functioning up to the
resetting intervention. The lock-out is signalled on the display of
the printed circuit board p.c.b. and can be reset only by using the
boiler reset button placed on the control panel electronic p.c.b.
(see section "10.1 Function" on page 27).
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 con-
nection).
• Faultyamedetection(faultydetectionelectrode,itswiringor
connection).
• Faulty condensate drainage.
• Faulty gas valve (faulty on-off operators or not electrically sup-
plied).
• Faulty Main electronic control/ignition p.c.b..
Other components like the primary circuit pressure switch can
temporarily stop the ignition of the burner but allow its ignition
when the cause of the intervention has stopped.
Figure 9.13 and Figure 9.14 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 Main electronic control/ignition p.c.b. several selection,
adjustment and protection devices are located. (Figure 9.2).
Some of these devices are directly accessible by the user (func-
tion control, temperature adjustment etc.) others, like the fuses,
are accessible by removing the main electronic p.c.b. lid.