Biasi M300V.2025 SM User manual

Service manual
Wall hung, fanflue, roomsealed, high efficiency gas boiler
RINNOVA ADAPTIVE
Models G.C. Appl. No.
M300V.2025 SM 47-583-46 COMBI BOILER
M300V.2530 SM 47-583-47 COMBI BOILER
M300V.3035 SM 47-583-48 COMBI 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.

- 3 -
TABLE OF CONTENTS
1 OVERALL INFORMATION..........................4
1.1 Overall View .....................................4
1.2 Hydraulic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2 GENERAL ACCESS AND EMPTYING HYDRAULIC
CIRCUITS.......................................5
2.1 Nomenclature ....................................5
2.2 Case panels......................................5
2.3 Control panel .....................................5
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 M300V SM . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.2 Circuit voltages ...................................9
4 FAULT FINDING.................................10
4.1 Display diagnostic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.2 Programming the maintenance period ................13
5 CONDENSING HEAT EXCHANGER.................15
5.1 Function........................................15
5.2 Removal .......................................15
5.3 Cleaning .......................................16
6 D.H.W. HEAT EXCHANGER .......................17
6.1 Function........................................17
6.2 Removal .......................................17
7 PUMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
7.1 Function........................................18
7.2 Removal pump head ..............................18
8 THREE WAY DIVERTER VALVE ....................19
8.1 Function........................................19
8.2 Checks.........................................19
8.3 Removal of the electric actuator .....................19
8.4 Removal of the three way diverter valve ...............20
8.5 Removal of the diverter group .......................20
9 MAIN ELECTRONIC CONTROL/IGNITION P.C.B. ......21
9.1 Function........................................21
9.2 Selection and adjustment devices....................21
9.3 Checking the temperature ..........................22
9.4 Setting the boiler control function modes ..............23
9.5 Checks.........................................24
9.6 Removal of the electronic control p.c.b ................24
9.7 Thermal control in the mode ...................26
9.8 Thermal control in the mode .....................27
10 CONTROL PANEL ELECTRONIC P.C.B. .............28
10.1 Function........................................28
10.2 Normally information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
11 GAS VALVE ....................................31
11.1 Function........................................31
11.2 Description of the parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
11.3 Adjustment - Chimney Sweep Function ...............31
11.4 Automatic calibration of the gas valve.................32
11.5 Checks.........................................33
11.6 Removal of the gas valve ..........................33
12 PRIMARY CIRCUIT PRESSURE SWITCH ............35
12.1 Function........................................35
12.2 Removal .......................................35
13 EXPANSION VESSEL AND PRESSURE GAUGE ......36
13.1 Function........................................36
13.2 Checks.........................................36
13.3 Removal of the expansion vessel ....................36
14 D.H.W. FLOW SWITCH, FILTER AND FLOW LIMITER ..37
14.1 Function........................................37
14.2 Description and location of parts - (Figure 14.2 - Figure
14.3) ..........................................37
14.3 Removal of the sensor.............................37
14.4 Checks.........................................37
14.5 RemovaloftheowswitchgroupandD.H.W.circuitlter . 38
15 NTC HEATING DELIVERY PROBE - NTC MAXIMUM
TEMPERATURE, C.H. TEMPERATURE RETURN
PROBE NTC, D.H.W. TEMPERATURE PROBE NTC....39
15.1 Function........................................39
15.2 Checks.........................................39
15.3 Removal of the NTC heating delivery probe - NTC
maximum temperature.............................39
15.4 Removal of the C.H. temperature return probe NTC......39
15.5 Removal of the D.H.W. temperature probe NTC.........40
16 BY-PASS VALVE ................................41
16.1 Function........................................41
16.2 Removal .......................................41
17 FAN AND AIR BOX ..............................42
17.1 Function........................................42
17.2 Removal of the Air box and the Fan ..................42
18 IGNITION / DETECTION ELECTRODE AND BURNER ..43
18.1 Function........................................43
18.2 Removal of the ignition / detection electrode............43
18.3 Removal of the front insulation panel .................43
18.4 Removal of the burner.............................43
18.5 Removal of the rear insulation.......................44
18.6 Checks.........................................44
19 FLUE TEMPERATURE PROBE NTC AND SAFETY
THERMAL FUSE ................................46
19.1 Function........................................46
19.2 Removal .......................................46
19.3 Checks.........................................46
20 CONDENSATE TRAP ............................48
20.1 Function........................................48
20.2 Check the cleanness of the trap .....................48
20.3 Removal .......................................48
21 SHORT SPARE PARTS LIST ......................49

- 4 -
OVERALL INFORMATION
1 OVERALL INFORMATION
1.1 Overall View
Figure 1.1
Condensing
heat exchanger
Flue temperature
probe NTC and
Safety thermal fuse
Ighition/Detection
electrode
NTC heating delivery probe -
NTC maximum temperature
Burner
Expansion
vessel
Fan
Condensate
trap
Air/gas mixer
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
D.H.W. flow switch
Gas valve
C.H. temperature
return probe NTC
Main circuit
pressure switch
1.2 Hydraulic diagram
Figure 1.2
Domestic hot water (D.H.W.) operation
D.H.W.
inlet
D.H.W.
outlet
Central heating (C.H.) operation
C.H.
waterflow
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
4
3
5
1 Right side panel
2 Front panel
3 Main electronic p.c.b. box
4 Control panel
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.
Fit the side panels and the front panel in the reverse order to that
described above.
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" and turn the control panel "E" (Figure
2.4).
Figure 2.4
D
E

- 6 -
GENERAL ACCESS AND EMPTYING HYDRAULIC CIRCUITS
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.
Terminal block lid removal
To gain access to the parts located inside the control panel pro-
ceed as follows:
1 Remove the front panel of the case.
2 Turn the control panel "F" (see section "2.3 Control panel" on
page 5).
3 Unscrew the screw "G" and lift the cover "H" to access the
electric power supply terminal block, remote and external
sensor (Figure 2.5).
Figure 2.5
F
G
H
4 Rotate the lid (Figure 2.6).
Figure 2.6
Main electronic p.c.b. lid removal
To get access to the main electronic p.c.b.:
5 Unscrew the screw "I" (Figure 2.7).
Figure 2.7
I
I
6 Free the hooks indicated and rotate the cover "K" and the lids
"J" (Figure 2.8).
Figure 2.8
J
K
7 Free the hooks indicated and rotate the cover "L" (Figure 2.9).
Figure 2.9
L

- 7 -
GENERAL ACCESS AND EMPTYING HYDRAULIC CIRCUITS
2.5 Emptying the primary circuit
1 ClosetheC.H.circuitowandreturncocks"M"(Figure2.10).
Figure 2.10
M
N
2 Remove the front and right panels of the boiler.
3 Loosen the central heating drain cock "O" (Figure 2.11) until
the boiler is completely emptied.
Figure 2.11
OPEN
CLOSED
O
4 To make draining easier, lift the plug "P" of the automatic re-
lief valve in Figure 2.12.
Figure 2.12
P
2.6 Emptying the D.H.W. circuit
1 Close the D.H.W. inlet cock "N" (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 M300V SM
Figure 3.1
N L
M
~
1
2
3ttt
3
1
4
2
M
~tt
3
1
4
2
IN
GND
5 V
t
1
2
3
4
IN
GND
5 V
bn = brown
bu = blue
bk = black
wh = white
rd = red
gy = grey
diverter valve
Three way
Electric supply Pump
gn = green
ye = yellow
vt = violet
og = orange
gnye = green/yellow
rdwh = red/white
Gas valve
D.h.w. flow
switch
Safety
thermostat
flow
C.h. temperature
probe NTC
Fan
Safety
Flue temp.
probe NTC
thermal fuse
Ignition
Flame detection
electrode
pressure switch
Primary circuit
return
C.h. temperature
probe NTC
D.h.w. outlet
temperature
probe NTC
External temp.
Remote
probe
terminal block
bn
bk
bn
bu
bu
gnye
rd
rd
rd
og
gy
gy
bu
gnye
bn
bk
gnye
gnye
bu bn bk bu
bn
bu bn
gnye
bk bk
bk
bk
bk
bu
bu
bk
bk
bu
rd
bu
bu
bu
bu bk
bk
bk bk
rd
rd
rdrd
rd
bk bk
bu bu
bu
bk
rd
rd
bk
bu
bu
bk
rd
bk
rd
bk
bk
bk
bk
rd
rd
bk
bk
og
rd
wh
wh
wh
wh
wh
wh
wh
wh
wh
wh
wh
wh
wh
wh

- 9 -
DIAGRAMS
3.2 Circuit voltages
Figure 3.2
230~
Electrical
voltages or frequency
with
burner on
during C.H. or D.H.W. operation
only during C.H. operation
only during D.H.W. operation
230~
Safety
thermostat
5 Vdc
Fan
1.....2 Vdc
Supply network
230~
Pump
230~ 230~0
3 way
diverter valve
24dc 65 ohm
Gas valv
e
33...200 Hz0...32 Hz
Main circuit
pressure switch
D.H.W.
Flow switch
0
24dc 67 ohm

- 10 -
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 / Detection electrode
Safety thermostat
Gas restrictor
Flue temp. probe NTC
Expansion vessel
Safety valve
Pressure gauge
External temp. probe
Display indicates ”E”
E01 + A B D C
E02 + C A B
E03 + A
E04 + B A
E05 + A
E06 + A
E07 + A
E08 + A
E10 + A B
E11 + C B
E12 + A
E13 + A B
E14 + A C B E14 + A B E18 + B A
E19 + A
E20 + A B
E21 + A B E22 + B A
The letter in the cells indicates the possible fault cause. A.....Z indicates the most probably (A) to less probably (....Z)

- 11 -
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 / Detection electrode
Safety thermostat
Gas restrictor
Flue temp. probe NTC
Expansion vessel
Safety valve
Pressure gauge
External temp. probe
Display indicates ”E”
E23 + A B
E24 + A B
E25 + C A B
E26 + B C A
E40 + A
E42 + A
E44 + D B C A
E50 + A
E62 + A E65 + A E68 + A B
E77 + B A
E79 + B A E78 + A B
E89 + A B
E91 + A B
E97 + A
E99 + A
L1 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 ”E” 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 “E” 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.
E01 + Safety lockout due to failed ignition.
E02 + Lockout due to safety thermostat.
E03 + Generic lockout.
E04 + Pump circulation failure, insufcient system
pressure or water pressure sensor not con-
nected.
E05 + Control anomaly: fan.
E06 + NTC heating delivery probe failure.
E07 + D.H.W. NTC probe failure / Hot water tank
sensor failure.
E08 + External NTC probe failure.
E10 + Lockoutduetotrippingoftheuegasprobe
and thermal fuse.
E11 + Parasiteame.
E12 + Return NTC probe failure.
E13 + Delta T M-R > 40K.
E14 + Temperature gradient circulation failure
(>2K/s).
E14 + Pump fault or primary temperature above
105°C.
E18 + NoΔTheatingatstartup.
E19 + Auxiliary Input Probe Anomaly.
E20 + EVG lockout (valve piloting hardware failure).
E21 + EVG lockout (valve control Relay Failure).
E22 + EVG lockout (ame after closing valve Ref.
EVG).
E23 + Gas valve modulator disconnected.
E24 + Anomaly due to probable chimney obstruc-
tion.
E25 + Flame loss for more than 6 consecutive
times.
E26 + Maximum deviation fault between the 2 heat-
ing NTC probes.
E40 + Detection of incorrect mains frequency.
E42 + Buttons fault.
E44 + Fault of cumulative gas valve timeout without
ame.
E50 + OT communication fault.
E62 + Calibration request.
E65 + System fails to control combustion and exits
modulator control parameters.
E68 + Probably low gas pressure.
E77 + System out modulator control parameters.
E79 + System out modulator control parameters.
E78 + Possible low gas pressure.
E89 + Internal error (usually hardware) or problems
with the mains electrical supply (excessive
distortion of waveform).
E91 + Maximum number of lockouts reached.
E97 + Power supply voltage low.
E99 + Cardnotcongured.
L01 Primary limitation in D.H.W. mode.
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 at the same
time the 2 keys "A" and "C" (Figure 4.1) and hold in for 5 sec-
ond until the display shows Figure 4.2.
Figure 4.1
A
B
C
Figure 4.2
2 Scroll the various menus using keys "A" or "C" (Figure 4.1)
until the LCD display indicates the letters PAr (Figure 4.3).
3 To enter the selected menu press key "B" (Figure 4.1) for 1
second.
Figure 4.3
4 Scroll the various menus using keys "A" or "C" (Figure 4.1)
until the LCD display indicates the letters P34 until the LCD
display indicates the value of parameter 34 (e.g.12 default
value) Figure 4.4.
Figure 4.4
5 To enter the selected parameter press key "B" (Figure 4.1)
for 1 second. The display will show the following (Figure 4.5).

- 14 -
FAULT FINDING
Figure 4.5
6 Pressing keys "A" or "C" makes it possible to change the
value of parameter 34 from 0to 48 months. It is possible to
set parameter 34 to 99 thereby disabling the maintenance
request (symbol Awill disappear from the display).
7 Bypressingkey"B"(Figure4.1)conrmationoftheinserted
value is obtained. The display will show the following (Figure
4.6) for 5 seconds, then move up to the next level.
Figure 4.6
8 To exit the parameters menu.
• wait 15 minutes without pressing any key;
• switch off the electric power supply;
• press the "A" and "C" keys simultaneously for 5 seconds (Fig-
ure 4.1) (return to previous level).

- 15 -
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 42.
3 Disconnect the detection / ignition electrode connector "D".
4 Disconnect the fan connector "E" by pressing the plastic hook
placed on the side of the connector (Figure 5.2).
5 Unscrew the nuts "F" (Figure 5.2).
6 Remove the fan-burner group "G".
7 Empty the primary circuit of the boiler.
8 Remove the clips "H" (Figure 5.2).
9 Loosen the connection "J" and slightly move the pipe "I" up-
wards, turn it towards left (Figure 5.2) and then move the pipe
downwards freeing it from the Condensing heat exchanger.
10 Loosen the connection "K" and slightly move the pipe "L" 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
Figure 5.3
M
N
11 Unscrew the screws "M" and remove the clamps (Figure 5.3).
12 Disconnect the connector "N" by pressing the plastic hook
placed on the side of the connector (Figure 5.3).
13 Remove the Condensing heat exchanger by levering it and
sliding it forwards.
14 Reassemble the Condensing heat exchanger carrying out
the removal operations in reverse order.
Ensure to tighten the nuts "F" - Figure 5.2 rmly.

- 16 -
CONDENSING HEAT EXCHANGER
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 - Chimney Sweep Function" on page 31 sec-
tion "11 GAS VALVE" on page 31.
Figure 5.4
O
Caution:
After any periodical servicing or disturbance the combustion
chamber silicon seal "O" 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.
Remove any limescale from the detection electrode
and replace it if worn.

- 17 -
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

- 18 -
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.
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 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 head
Warning: isolate the boiler from the mains electrici-
ty supply before removing any covering or compo-
nent.
1 Remove the front case panel.
2 Empty the primary circuit of the boiler.
3 Disconnect the connector "B" (Figure 7.2).
4 Unscrew the four screws "C" and remove the pump head "A".
Figure 7.2
A
B
C
Reassemble the pump head carrying out the removal operations
in the reverse order. When reassembling the pump head, check
the correct position of the gasket and tighten the screws "C" pro-
ceeding diagonally around the pump.

- 19 -
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
9,4Kohm
Open circuit
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.

- 20 -
THREE WAY DIVERTER VALVE
Warning: Please note the electric actuator is ener-
gized 240VAC even if the boiler is in a standby con-
dition.
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 19).
4 Unscrew the three way diverter valve "F" Figure 8.5.
Figure 8.5
F
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.
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 19).
4 Disconnect D.H.W. temperature probe NTC "G" (Figure 8.6).
5 Unscrewtheconnector"H" (Figure8.6),theC.H.owcon-
nector and the D.H.W. outlet connector.
6 Remove the D.H.W. heat exchanger (see "6.2 Removal" on
page 17).
7 Unscrew the screw "I" and remove the diverter group.
Figure 8.6
G
H
I
8 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.