Blasi GARDA HE M96.24SM/B2, M96.28SM/B2, GARDA HE SILVER M96.24SM/D2, M96.28SM/D2 gas boiler Service manual
Below you will find brief information for gas boiler GARDA HE M96.24SM/B2, gas boiler GARDA HE M96.28SM/B2, gas boiler GARDA HE SILVER M96.24SM/D2, gas boiler GARDA HE SILVER M96.28SM/D2. This service manual provides detailed information on operation, maintenance and troubleshooting procedures for these high efficiency gas boilers.
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Wall hung, fan flue, room sealed, high efficiency gas boiler
Service manual
GARDA HE
Models:
M96.24SM/B2
M96.28SM/B2
G.C. Appl. No.
47---583---03A
47---583---04A
GARDA HE SILVER
Models:
M96.24SM/D2
M96.28SM/D2
G.C. Appl. No.
47---583---03B
47---583---04B
Leave this manual adjacent to the gas meter
Table of contents
1
1.1
1.2
2
3
3.1
3.2
3.3
2.1
2.2
2.3
2.4
2.5
2.6
4
Overall information . . . . . . . . . . . . . . . . . .
Overall View . . . . . . . . . . . . . . . . . . . . . . . . .
Hydraulic diagram . . . . . . . . . . . . . . . . . . . .
General access and emptying hydraulic circuits . . . . . . . . . . . . . . . . . . . .
Nomenclature
Body panels
. . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . .
Control panel . . . . . . . . . . . . . . . . . . . . . . . .
Access to the sealed chamber
Emptying the primary circuit
Emptying the d.h.w. circuit
. . . . . . . . .
. . . . . . . . . . .
. . . . . . . . . . . .
Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . .
Wiring diagram
Functional flow diagrams
Circuit voltages
. . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . .
Fault finding . . . . . . . . . . . . . . . . . . . . . . . .
6
6.1
6.2
7
7.1
7.2
5
5.1
5.2
5.3
Primary heat exchanger
Function
Removal
Cleaning
. . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Condensing heat exchanger
Function
Removal
. . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
D.h.w. heat exchanger
Function
Removal
. . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
9
9.1
9.2
9.3
9.4
8
8.1
8.2
8.3
Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Function
Checks
Removal
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Three way diverter valve . . . . . . . . . . . . .
Function
Checks
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Removal of the electric actuator
Removal of the diverter group and its internal parts
. . . . . . . .
. . . . . . . . . . . . . . . . . .
14
10 Electronic control/ignition p.c.b.
. . . . . .
. . . . . .
15
10.1
Function
10.2
10.4
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Selection and adjustment devices
10.3
Checking the temperature
Operation lights
. . . . . .
. . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . .
10.5
Setting the boiler control function modes 17
15
15
16
17
10.6
10.7
Reignition frequency setting . . . . . . . . . . .
Ignition gas pressure adjustment . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. .
18
18
10.8
Checks 19
10.9
Removal of the electronic control p.c.b
19
10.10 Thermal control in the ” ” mode 21
10.11 Thermal control in the ” ” mode
10.12 Ignition and control sequence
. . . . . .
. . . . . . . . . .
21
22
13
13
13
13
12
12
12
12
10
10
10
11
11
11
9
9
9
9
4
4
5
6
7
2
2
3
2
2
3
3
1
1
1
11
11.2
11.3
Modulating gas valve
11.1
Function
. . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nomenclature of the parts
Adjustment
11.4
Checks
. . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.5
Removal of the gas valve . . . . . . . . . . . . . .
12 Primary circuit flow switch
12.1
Function
12.2
Checks
12.3
Removal
. . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
13 Expansion vessel and temperature--pressure gauge . . . . . . . .
26
13.1
Function
13.2
Checks
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.3
Removal of the expansion vessel . . . . . . .
26
13.4
Removal of the temperature---pressure gauge
26
26
26
25
25
25
25
23
23
23
23
24
24
14
14.1
14.2
D.h.w. flow switch, filter and flow limiter 27
Function
14.3
Checks
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nomenclature and location of parts
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.4
Removal of the flow switch sensor
14.5
Removal of the flow switch group and d.h.w. circuit filter
14.6
Flow limiter
. . . . .
. . . . . .
. . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . .
27
27
27
27
28
28
15 Temperature probe
15.1
Function
15.2
Checks
15.3
Removal
. . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
16 By--pass valve
16.1
Function
16.2
Removal
. . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
30
30
30
29
29
29
29
17 Fan, venturi device and
Air pressure switch . . . . . . . . . . . . . . . . . .
31
17.1
Function
17.2
Checks
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
31
31
17.3
Removal of the Fan . . . . . . . . . . . . . . . . . . .
32
17.4
Inspection and removal of venturi device 32
17.5
Removal of the Air pressure switch . . . . .
33
18 Ignition and detection electrodes
18.1
Function
18.2
Checks
18.3
Removal
. . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
19 Safety thermostat
19.1
Function
19.2
Checks
19.3
Removal
. . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
20 Flue temperature probe NTC
20.1
Function
20.2
Checks
20.3
Removal
. . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
36
36
36
36
35
35
35
35
34
34
34
34
21 Condensate trap
21.1
Function
21.2
Removal
. . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
22 Short spare parts list . . . . . . . . . . . . . . . .
37
37
37
38
1
Overall information
1.1
Overall View
Flue thermostat
Air pressure switch
Fan
Condensing heat exchanger
Expansion vessel
Main heat exchanger
Combustion chamber
Burner
Ignition electrodes
Detection electrode
Diverter valve
C.h. temp.
probe
Main circuit flow switch
D.h.w. temp.
probe
Gas valve
Control panel
1.2
Hydraulic diagram
Central heating (c.h.) operation
Safety thermostat
Automatic air release valve
Condensate trap
Pump
D.h.w.
heat exchanger
Domestic hot water (d.h.w.) operation
C.h.
water return
C.h.
water flow
D.h.w.
inlet
D.h.w.
outlet
1
2
General access and emptying hydraulic circuits
2.1
Nomenclature
1
A
2
6
3
Fig. 2
To remove the side panels loosen the screws
B and C
(Fig. 3), bring the base of the panels away from the boiler and lift them, freeing them from the top hooks.
D
5
4
Fig. 1
1
2
3
4
5
6
Right side panel
Front panel
Control panel lid
Control panel cover
Service panel
Left side panel
2.2
Body panels
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
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 (Fig. 2), lift the panel and remove it.
2
B
C
Fig. 3 --- bottom view of the boiler
2.3
Control panel
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
2
3
To gain access to the parts located inside the control panel proceed as follows:
1 Remove the front panel of the case
4
Loosen the screws B and C (Fig. 3).
Remove the screws
D
Move the lower part of the side panels as indicated in Fig. 4 and pull the control panel.
When completely pulled out, the panel can rotate
45˚ downwards to facilitate the service operations on the internal parts.
Fig. 4
5
6
Remove the screws E and remove the service panel (Fig. 5);
To gain access to the electronic regulation PCB remove the screws
F and remove the control panel lid (Fig. 5);
F
General access and emptying hydraulic circuits
To gain access to the parts contained in the sealed chamber it is necessary to remove the lid of the sealed chamber.
For this purpose, remove the front and side panels of the case, remove the screws G as indicated in Fig. 6 and remove the lid.
1
2.5
Emptying the primary circuit
Close the c.h. circuit flow and return cocks H.
(Fig. 7).
J
H
E
Fig. 5
2.4
Access to the sealed chamber
F
H
Fig. 7 --- bottom view of the boiler
2
3
4
Remove the front and right panels of the boiler.
Open the drain tap I (Fig. 8) until the boiler is completely emptied.
Close drain tap again once the emptying has been completed.
G
Fig. 6
G
I
Fig. 8
5
6
2.6
Emptying the d.h.w. circuit
Close the d.c.w. inlet cock
J (Fig. 7);
Open one or more hot water taps until the boiler has been completely emptied.
3
3
Diagrams
3.1
Wiring diagram
Electric supply terminal block
External controls terminal block
Three way diverter valve
Pump
L N
3 2 1
1
M
~ 3
2 bn bu bk
M
~
Fan
M
~ bu bn gn
Primary circuit flow switch
Air pressure switch
Ignition electrodes
Flame detection electrode bk bk gy gy
Condensate trap
F2
F1
X1
X5 bn bu bu
X6
K1
K3 K4
X7
X3 wh gy
K2
X4 wh wh bk bk gy gy bk
X2
LD3 LD2 LD1
P4
P5
SB1
LD4
X8
X11
4
1 4 wh gy
Remote control terminal block wh t bu rd
D.h.w. flow switch
C.h. temperature probe NTC gy* gy bu bn bk bk
Modulating gas valve
Safety thermostat wh wh t rd rd t rd bk wh gn
Flue temperature probe NTC
D.h.w. temperature probe NTC
Time switch bn = brown bu = blue bk = black wh = white rd = red gy = grey gn = green ye = yellow vt = violet og = orange gnye = green/yellow
* alternative, yellow
3.2
Functional flow diagrams
General layout
J1--- 1 Fuse 3,15 A
L
PTC
Heat request on d.h.w.
L
J1--- 1 Fuse 3,15 A
L --- LINE N --- NEUTRAL
ACTIVE CIRCUIT
INACTIVE CIRCUIT
Heat request on c.h.
L
J1--- 1 Fuse 3,15 A
PTC
PTC
Diagrams
Transformer
Transformer
Transformer
Electronic control p.c.b.
(low voltage section)
J3--- 5
J3--- 3
Three way diverter valve
J3--- 4
J3--- 1
Pump
J3--- 2
J2--- 5
Full sequence ignition device
J2--- 4
Electronic control p.c.b.
(low voltage section)
J3--- 5
J3--- 3
Three way diverter valve
J3--- 4
J3--- 1
Pump
J3--- 2
J2--- 5
Full sequence ignition device
J2--- 4
Electronic control p.c.b.
(low voltage section)
J3--- 5
J3--- 3
Three way diverter valve
J3--- 4
J3--- 1
Pump
J3--- 2
J2--- 5
Full sequence ignition device
J2--- 4
J1--- 2
N
J1--- 2
N
J1--- 2
N
5
6
Diagrams
3.3
Circuit voltages
Electrical voltages with burner on
Pump
3 way diverter valve
Modulating
Gas valve
Fan
Supply network during c.h. or d.h.w. operation only during c.h. operation only during
d.h.w. operation
F2 F1
X1
X5
X6
K1
K3 K4
X7
K2
X4
X3
X2
LD3 LD2 LD1
P4
Air switch pressure
Safety thermostat
P5
SB1
LD4
--- (8)
--- (7)
--- (4)
--- (3)
--- (2)
--- (1) or)
) trap and perat rators ge gau e alv tyv l vesse ion s mostat ther t ermosta ode lectr ctione e trod elec switch ssure ce evi urid vent ve val ass e rob p.p
em obe p.pr
em uitt irc b.) go ope itch sw atin off p.c.
h b.
odul low nic itc sw tro n--p.c.
r itf ilte circu ve(m ve(o ttings valve lec (E low nic w.f
es ctro rter erse val val w.f
nc w.t
- -p and pre ition tyth ctor ans ssure
Dive
D.h.
Boil
Gas
Gas
Main
D.h.
Mai
D.h.
By-
Fan
Air
Ign
Dete
Safe
Flue
Inje
Exp
Safe
Pre
Ele
Fus
Pump anger xch ate w.he
D.h.
uit irc w.c
D.h.
uit circ C.h.
ipe np drai te nsa Conde s pipe ne yli suppl
Flue
Gas e lin upply ers Pow d pre lam nal sig out k--Loc
ON OFF
7
--- (8)
--- (7)
--- (4)
--- (3)
--- (2)
--- (1) or)
) trap and perat rators ge gau e alv tyv l vesse ion s mostat ther t ermosta ode lectr ctione e trod elec switch ssure ce evi urid vent ve val ass e rob p.p
em obe p.pr
em uitt irc b.) go itch sw atin ope off odul low n--r itf ilte ve(m val circu ve(o ttings p.c.
b.
h nic itc sw tro p.c.
valve lec (E nic low w.f
es ctro rter erse val w.f
nc w.t
- -p and pre ition tyth ctor ans ssure Pre
Safe
Dete
Main
Gas
D.h.
Air
Ign
Fus
Ele
Exp
Inje
Flue
Safe
D.h.
Mai
D.h.
Gas
Boil
Dive
By-
Fan
Pump anger xch ate w.he
D.h.
uit irc w.c
D.h.
uit circ C.h.
ipe np drai te nsa Conde s pipe ne yli suppl Gas
Flue e lin upply ers Pow
8
d pre lam nal sig out k--Loc
OFF F
5
Primary heat exchanger
5.1
Function
The primary heat exchanger A in Fig. 9 has the function of transferring heat produced from combustion of the gas to the water circulating in it.
D
C
A
B
C
L
M
F
E
K
Fig. 9
The hydraulic circuit is composed of 8 elliptical pipes connected in parallel (Fig. 10).
Fig. 10
1
2
3
4
5
6
5.2
Removal
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
Remove the case panels and the sealed chamber lid (see section 2).
Empty the primary circuit of the boiler.
Remove the combustion chamber lid
B by unscrewing the screws C and removing the clamp
D (Fig. 11).
Remove the screws E and the plate F.
Loosen the connection
G and slightly move the pipe H upwards.
Remove the clip I and the safety thermostat J. It is not necessary to disconnect it from the wiring.
Fig. 11
8
9
7 Loosen the connection K and move the pipe L downwards freeing it from the connection of the primary het exchanger.
Remove the clip
M
Move the pipe
N upwards freeing it from the connection and rotate towards right.
10 Remove the heat exchanger by sliding it forwards.
11 Reassemble the boiler carrying out the removal operations in reverse order.
Fit the clip I with the arrow pointing upwards as illustrated in
Fig. 11.
IMPORTANT -- do not force the connection
G when tighting it.
5.3
Cleaning
If there are deposits of soot or dirt between the blades of the heat exchanger, clean with a brush or non---metallic bristle brush.
In any case, avoid any actions that can damage the protective varnish with which the exchanger has been covered.
Warning: After cleaning or replacement as detailed above, if it deemed necessary to undertake a combustion analysis, refer to the appropriate chapter Maintenance of the installation instructions manual.
9
H
N
G
J
I
6
Condensing heat exchanger
6.1
Function
The return water flows through the condensing heat exchanger A in Fig. 12 and Fig. 13.
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.
A
6
7
8
Remove the clip I and move the pipe J downwards freeing it from the connection, then turn it towards right.
Using pliers, remove the spring K moving it downwards and disconnect the rubber pipe
L.
Remove the bracket M by unscrewing the screws that hold it on the frame.
9 Rotate the exchanger as indicated by the arrow and remove it towards the front of the boiler.
10 Remove the clip N and the pipe H.
A
M
F
E
D
J
N
H
B
C
K
L
G
Fig. 12
1
2
3
4
5
6.2
Removal
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
Remove the case panels and the sealed chamber lid (see section 2).
Empty the primary circuit of the boiler.
Remove the fan D in Fig. 13 (see section 17.3) and the air pressure switch E (see section 17.5).
Remove the flue temperature probe NTC
F (see section 20.3)
Completely loosen the connection G and slightly move the pipe H upwards.
Fig. 13
11 Reassemble the exchanger carrying out the removal operations in reverse order.
After reassembling ensure that the fan--exchanger and exchanger--elbow gaskets are correctly mounted and ensure a good sealing.
Warning: After cleaning or replacement as detailed above, if it deemed necessary to undertake a combustion analysis, refer to the appropriate chapter Maintenance of the installation instructions manual.
10
7
D.h.w. heat exchanger
7.1
Function
The d.h.w heat exchanger A in Fig. 14 and Fig. 16 allows the instantaneous transfer of heat from the primary hydraulic circuit to the water destined for d.h.w use.
A
1
2
3
7.2
Removal
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
Remove the front and right hand side panels of the case.
Empty the primary circuit and the d.h.w circuit of the boiler.
Completely unscrew the two Allen key screws
B
(Fig. 16) which hold the exchanger to the brass groups.
A
Fig. 14
The schematic structure is shown in Fig. 15.
B
Fig. 16
4 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.
Attention. When reassembling the exchanger be sure to put the off center location/securing pin indicated in Fig. 17 towards the left side of the boiler.
Fig. 15
Primary hydraulic circuit
Domestic hot water circuit
Fig. 17
11
8
Pump
8.1
Function
The pump A in Fig. 18 and Fig. 19 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).
n
Check that the impeller is integral with the rotor.
With the boiler off remove the front and right hand side case panels, 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 firmly joined to the rotor.
1
2
3
4
5
8.3
Removal
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
Remove the front and right hand side case panels
Empty the primary circuit of the boiler.
Extract and lower the control panel.
Disconnect the connector B (Fig. 19).
Loosen the connection
C, remove the fork D and the pipe E.
A
B
D
A
Fig. 18
8.2
Checks
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
n
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 release plug of the pump and turn the rotor with a screwdriver.
n
Check the electrical continuity.
With the boiler off, remove the front panel and disconnect the connector
B (Fig. 20).
Measure the electrical resistance between the pump supply connections.
Electrical resistance of the windings (at ambient temperature) must be about 230 Ω n
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.
12
C E
7
8
9
Fig. 19
6 Remove the fork
F (Fig. 20) and the connection of the capillary pipe of the pressure gauge.
Remove the locking plate
G
Completely loosen the connection H.
Unscrew the two screws I that hold the pump on the frame and remove the pump.
H F I G
Fig. 20
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 brass group.
9
Three way diverter valve
9.1
Function
The diverter valve A (Fig. 21) 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.
B
A bn = brown bu = blue bk = black
Fig. 22 --- D.h.w. mode
B
Spindle B not visible
9,4 Kohm
Open circuit
Spindle B visible bn = brown bu = blue bk = black
Open circuit
9,4 Kohm
Fig. 21
9.2
Checks
n
Check the electrical continuity
Fig. 22 indicates the relationship between the electric command 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.
Fig. 23 indicates the relationship between the electric command 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 figures the relationship between the position of the actuator and the resistance of the motor windings
(the motor must be disconnected from the wiring) is also given.
Fig. 23 --- C.h. mode
1
2
3
9.3
Removal of the electric actuator
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
Remove the front case panel.
Disconnect the connectors C (Fig. 24).
Remove the fixing 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 Fig. 22 or to the wiring diagram in section 9.2 for the correct wiring connection.
13
Three way diverter valve
9 Unscrew the screw M and remove the diverter group.
K
E D C
Fig. 24
3
4
1
2
5
6
9.4
Removal of the diverter group and its internal parts
Remove the front and both side case panels.
Empty the primary circuit and the d.h.w circuit of the boiler.
Remove the electric actuator (see section 9.3).
Remove the fixing spring F (Fig. 25) and remove the primary circuit flow switch G.
Disconnect both c.h. and d.h.w. temperature probe, respectively
H and I .
Unscrew the connector
J, the c.h. flow connector and the d.h.w. outlet connector.
L
M
Fig. 26 Rear view of the boiler
10 Refer to the exploded view in Fig. 27 to remove the internal parts of the three way diverter valve.
J
H
G F I
Fig. 25
7
8
Remove the d.h.w. heat exchanger (see section
7.2).
Remove the fork K and move away the pipe L
(Fig. 26).
Fig. 27
11 Reassemble the diverter group carrying out the removal operations in the reverse order.
14
10
Electronic control/ignition p.c.b.
10.1
Function
Inlet Information
On the Electronic control/ignition p.c.b.......
Function control
C.h. temperature adjustment
D.h.w. temperature adjustment
Boiler reset button
(control panel fascia)
From other boiler devices....
C.h. temperature probe NTC
D.h.w. temperature probe NTC
D.h.w. flow switch
Primary circuit flow switch
Air pressure switch
Flue temperature probe NTC
Safety thermostat
Flame detection electrode
Room thermostat (if fitted)
Time switch
Fig. 28
Outlet command
Pump
Three way diverter valve
On---off operators (gas valve)
Modulation operator (gas valve)
Fan
Ignition electrodes
Appliance operation lights*
Lock---out signal lamp*
*control panel fascia
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 circuits 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 consequently acts with outlet commands on other components of the boiler (Fig. 28).
The Electronic control/ignition p.c.b. is also a full sequence ignition 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 flame during the entire period in which it is activated, supplies the fan and checks its functioning by means of the signal coming from the air pressure switch.
The Electronic control/ignition p.c.b. has a
safety func-
tion 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 activate the lock state. The causes of a lock state could be: f
The intervention of the safety thermostat (overheat of the primary circuit).
f
The intervention of the flue temperature probe
(overheat of the combustion products).
f
A fault on gas supply.
f
Faulty ignition (faulty ignition electrodes, their wiring or connection).
f
Faulty flame detection (faulty detection electrode, its wiring or connection).
f
Faulty condensate drainage.
f
Gas injectors blocked.
f
Faulty modulation gas valve (faulty on---off operators or not electrically supplied).
f
Faulty Electronic control/ignition p.c.b..
Other components like the air pressure switch can temporarily stop the ignition of the burner but allow its ignition when the cause of the intervention has stopped.
Fig. 45 shows the sequence of the operations that are carried out at the start of every ignition cycle and during normal functioning.
10.2
Selection and adjustment devices
On the Electronic control/ignition p.c.b. several selection, adjustment and protection devices are located.
(Fig. 29).
15
Electronic control/ignition p.c.b.
Some of these devices are directly accessible by the user (function control, temperature adjustment potentiometers etc.) others are accessible by removing the service panel or the control panel lid.
1
2
3 4 5
11
10 9 8 7 6
8
9
6
7
Fig. 29
1
2
3
4
5 x1 connector x6 connector x7 connector x4 connector x2 connector
Lock---out signal lamp
Boiler reset button
Function control / C.h. temperature adjustment
D.h.w. temperature adjustment
10 Appliance operation lights
11 Fuse 3,15 A F
10.3
Checking the temperature
The Electronic control/ignition p.c.b. makes it possible to separately adjust the c.h. water flow 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 (8 and
9 in Fig. 29) 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 (Fig. 30), 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 modulation of the gas valve, consequently changing the useful output of the boiler.
Fig. 30
When the boiler functions in d.h.w. (Fig. 31), the signal coming from the d.h.w. temperature probe is compared with the signal given by the control panel through the adjustment made by the user (knob ).
16
Electronic control/ignition p.c.b.
With the boiler switched ON ( or ) all the lamps
(10 in Fig. 29) are activated.
The following table gives the relationship between each of the possible lamp combinations and their meaning.
75
˚C
Fig. 31
Normally, the result of the comparison between these two signals directly operates the adjustment elements of the gas valve modulation device, adjusting the useful output generated in order to stabilize the temperature of the exiting water.
If during the d.h.w. mode operation, the temperature of the primary circuit goes over 75°C, the useful output is automatically reduced so that the primary circuit cannot reach excessive temperatures.
The control sequences in function and in function are illustrated in detail in sections 10.10 and 10.11.
10.4
Operation lights
The Electronic control/ignition p.c.b. is provided with three lamps (L.E.D. indicators) 10 in Fig. 29 that give optical information during the operation of the boiler.
The green lamp on the left gives information whether the boiler is in stand---by mode or during the normal operation of the boiler.
The following table gives the relationship between the lamp indication and its meaning.
A short pulse every 4 seconds
Boiler in stand---by condition.
(function control in position).
Anti---freeze system active.
Boiler ON condition
(function control in position) or
1 second ON 1 second OFF
Normally operating boiler
(see the previous table for details)
C.h. operation
D.h.w. operation
Frost protect operation
D.h.w. operation
Excessive temperature on primary circuit
Faulty c.h. temperature probe NTC
Faulty d.h.w temperature probe NTC
Faulty flue temperature probe NTC
Faulty primary circuit
(no water or absence of flow)
Faulty air pressure switch
Lack of burner ignition (no ignition signal from the full seqence ignition device)
Safety thermostat lock out
Flue temperature probe NTC lock out
Lack of power supply or fauly electronic control p.c.b. *
Faulty Electronic control/ignition p.c.b.. *
Lamp
OFF
Lamp
ON
Flashing lamp, alone or simultaneously with an other lamp.
Flashing lamp, alternate with another lamp.
* These conditions are normal only for a short time when the power supply is applied to the boiler.
If permanent they indicate a faulty p.c.b.
10.5
Setting the boiler control function modes
It is possible to select the various boiler control function modes by using the function selector knob A and the
D.h.w. temperature control knob B (Fig. 32).
During the function modes setting, the boiler does not operate.
Fig. 32
E B A C D
17
Electronic control/ignition p.c.b.
10.6
Reignition frequency setting
It is possible to select the minimum time that must pass between two ignitions of the burner in c.h. function mode.
1 Turn the boiler ON positioning the function selector knob A as indicated in Fig. 33.
2
3
4
Remove the front panel of the case.
Open the gas valve outlet pressure test point (7, see section 11.2) and connect the gauge.
Turn the boiler ON positioning the function selector knob A as indicated in Fig. 36 and ensure that the timer selector switch and room thermostat, if fitted, are set to “heat demand”.
Run the boiler in c.h. mode (do not open any d.h.w. tap).
Fig. 33
E
2
3
B A C D
Keep pressed the reset button C for about 10 seconds until the lock---out signal lamp D blinks.
The lamps E should give the indication as in
Fig. 34 (reignition frequency). If not, press the reset button repeatedly to obtain it.
Where:
Lamp OFF
Lamp ON
Fig. 34
At this step it is possible to visualize the current setting by keeping the reset button C pressed for more than 5 seconds. The lamps E will flash a number of times corresponding to the setting (Fig. 35).
4 To change the setting turn the knob B on a position corresponding to the desidered delay.
By turning the knob B, the lock---out signal lamp
D blinks quickly (2 per seconds) indicating that the setting has changed and must be memorised.
4
3 5 1/2
1 1/2
7
0
8 1/2
Fig. 36
E
5
6
B A
C D
Keep pressed the reset button C for about 10 seconds until the lock---out signal lamp D blinks.
The lamps E should give the indication as in
Fig. 37. If not, press the reset button repeatedly to obtain it.
Where:
Lamp OFF
Lamp ON
Fig. 37
7 Keep pressed the reset button C for about 5 seconds until the lock---out signal lamp D is switched
OFF.
The boiler runs in c.h. mode and the lamps E give the indication as in Fig. 38.
Where:
Lamp OFF
Flashing lamp, alone or simultaneously with an other lamp.
Fig. 38
8 Rotate the knob B on a position corresponding to an adequate ignition pressure.
Refer to the value indicated in the tables of the
User/Installation manual (
Technical information
section, Gas pressures at the burner table).
By rotating clockwise the pressure increases.
9 Make a note of the position of the knob B.
10 Turn the boiler OFF and ON positioning the function selector knob A as indicated in Fig. 39
B
Delay (minutes)
Setting No.
Fig. 35
5
6
To memorize the setting keep pressed the reset button C for about 5 seconds until the lights E briefly blinks simultaneously.
To reset the boiler to the normal operation turn it
OFF and ON by the function selector knob A. In any case, the boiler automatically resets to its normal operation after 10 minutes.
Factory setting = 3minutes
1
10.7
Ignition gas pressure adjustment
Turn the boiler OFF.
18
Fig. 39
E B A
C D
11 Keep pressed the reset button C for about 10 seconds until the lock---out signal lamp D blinks.
12 Press the reset button C repeatedly (4 times) until the lamps E give the indication as in Fig. 40 (ignition pressure adjustment mode).
Where:
Lamp OFF
Lamp ON
Fig. 40
13 Turn the knob B to the minimum (fully counterclockwise) and then on the position corresponding to the position obtained on step 8.
By turning the knob B, the lock---out signal lamp
D blinks quickly (2 per second) indicating that the setting has changed and must be memorised.
14 To memorize the setting keep pressed the reset button C for about 5 seconds until the lights E briefly blinks simultaneously.
15 To reset the boiler to the normal operation turn it
OFF and ON by the function selector knob A checking the ignition pressure and that the burner lights up uniformly. In any case, the boiler automatically resets to its normal operation after
10 minutes.
10.8
Checks
n
Check that the fuses are complete
If the Electronic control/ignition p.c.b. does not supply any device (pump, fan, etc.) check that the fuses 11
(Fig. 29) are complete.
If a fuse has blown replace it with one that has the same characteristics after having identified the reason for failure.
n
Lock sequence
Start the boiler until the burner is ignited.
With the burner firing, interrupt the gas supply. The
Electronic control/ignition p.c.b. must carry out three complete ignition cycles and then, after about 3 minutes, goes to lock---out state.
By turning the boiler on and off by means of the function switch the device must not unlock and the burner must not turn on.
n
Fan functioning device
With the boiler operating and the burner on, open the negative pressure test point of the Venturi device.
At the moment of opening the burner must turn off.
10.9
Removal of the electronic control p.c.b
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
Electronic control/ignition p.c.b.
When replacing the Electronic control/ignition p.c.b. it is advisable to go through the setting modes of the boiler
1
2
3
Gain access to the parts located inside the control panel as explained in the section 2.3 of this manual.
Remove all the wiring connected to the Electronic control/ignition p.c.b..
To disconnect the connectors x1, x6 and x7 (1, 2 and 3 in Fig. 29) delicately flex the hook present on one side of each socket.
To disconnet the connectors x4 and x2 (4 and 5 in Fig. 29) press delicately the hook present on one side of each connector.
Remove the spindles of the c.h. and d.h.w. temperature adjustment knobs by delicately pulling them with pliers in the direction shown by the arrow in Fig. 41.
Fig. 41
4
5
6
Unscrew the four screws that hold the Electronic control/ignition p.c.b. on to the control panel.
Remove it by lifting its rear edge and freeing it from any of the wiring.
Re---assemble the Electronic control/ignition p.c.b. following the removal procedures in the reverse order.
Important
When re---assembling the Electronic control/ignition p.c.b.:
7
8
9
Fit the p.c.b. into the control panel by first inserting the front lower edge under the control knob shafts. Lower the rear edge and ensure that no wiring is trapped beneath.
Insert the spindles in the control panel knobs untill the notch A (Fig. 42) reaches the potentiometer edge. It is not necessary to force them in the knob.
While tightening the screws that fix the Electronic control/ignition p.c.b. on the control panel, keep the p.c.b. towards the control panel fascia making sure of the contact between the boiler reset button B and the tab C (Fig. 42).
19
Electronic control/ignition p.c.b.
Fig. 42
Attention
A
A
B
C
After installing the Electronic control/ignition p.c.b. :
10 Make sure the c.h. ( ) and d.h.w. ( ) temperature adjustment knobs can move freely for the complete range.
If not, remove the spindle again as described at step 3, turn the knob half a turn and re---insert the spindle.
11 Operate the boiler and close the gas inlet cock so that the boiler goes into the safety lock---out state.
Verify the correct operation of the boiler reset button by pressing and releasing it.
Warning: After cleaning or replacement as detailed above, if it deemed necessary to undertake a combustion analysis, refer to the appropriate chapter Maintenance of the installation instructions manual.
20
10.10
Thermal control in the ” ” mode
See functioning with the function control in the mode
(sec. 10.11)
YES
Switch in the function mode
Taking water from the domestic hot water circuit?
NO
Electronic control/ignition p.c.b.
YES
Is primary circuit temperature higher than that selected?
NO
NO
Circulator off
Operates motorised valve
Ignition device off
Fig. 43
10.11
Thermal control in the ” ” mode
Request for heat from room thermostat?
YES
Starts the circulator
Operates motorised valve
Supplies the ignition device
YES
Switch in the function mode
Taking water from the domestic hot water circuit?
NO
Circulator off
Ignition device off
Circulator on
YES
Supplies the ignition device
Is domestic hot water outlet temperature lower than that required?
NO
Ignition device off
Fig. 44
21
Electronic control/ignition p.c.b.
10.12
Ignition and control sequence
YES
Ignition request lock memorised?
NO
NO
Air pressure switch at rest?
YES starts fan
NO
NO
Air pressure switch at work?
YES beginning of wait period
NO presence of flame?
Air pressure switch at work?
YES starts ignition discharges opens gas valve beginning of ignition period
YES cancels lock
NO end of ignition period?
YES
NO flame presence?
closes gas valve stops fan interrupts ignition discharges memorizes lock turns on lock---out light
YES interrupts ignition discharges gas valve open
NO reset push---button pressed?
YES closes gas valve
YES flame presence?
NO
YES
Air pressure switch at work?
NO
NO
Safety thermostat opens the circuit?
YES
Fig. 45
22
11
Modulating gas valve
11.1
Function
The Modulating gas valve A in Fig. 46 controls the gas inflow to the boiler burner.
1
8
7
2
6
5
3
4
A
Fig. 46
By means of an electric command given to the on---off operators the passage of the gas through the Modulating gas valve can be opened or closed.
By means of an electric command given to the modulation operator the pressure can be varied and therefore the gas flow rate to the burner (modulation). The modulation operator has mechanical components which allow the adjustment of the minimum and maximum pressure exiting the valve.
5
6
3
4
1
2
7
8
11.2
Nomenclature of the parts (Fig. 47)
Minimum gas pressure adjustment
Maximum gas pressure adjustment
Modulation operator’s electric connectors
On---off operators electric connector
On---off operators
Gas valve inlet pressure test point
Gas valve outlet pressure test point
Modulation operator
Fig. 47
1
2
3
4
5
11.3
Adjustment
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
Remove the front panel of the case.
Open the gas valve inlet pressure test point (6 in
Fig. 47) at the valve input, connect a suitable pressure gauge and check the gas pressure of the supply network.
Remove the gauge and close the pressure test point 6.
Open the gas valve outlet pressure test point (7 in Fig. 47) and connect the gauge;
Remove the protection cap
B (Fig. 48) from the mechanical pressure adjustment components levering with a flat screwdriver in the slots
C.
23
Modulating gas valve
C B
3 Measure the electrical resistance between the connector pins of the on---off operators as illustrated in Fig. 49.
On---off operator approx. 4 180 Ω*
Fig. 48
6
7
8
Start the boiler at its maximum power.
Operate the boiler in d.h.w. mode or ensure that the boiler is not range rated if the test is carried out in c.h. mode.
Rotate the maximum gas pressure adjustment (2 in Fig. 47) until you obtain the required pressure
(by rotating clockwise the pressure increases).
Turn the boiler off and disconnect one of the two connectors (3 in Fig. 47).
9 Start the boiler and rotate the minimum gas pressure adjustment (1 in Fig. 47) until you obtain the required pressure (by rotating clockwise the pressure increases).
10 Turn the boiler off and re---connect the wire to the modulating operator.
11 Start the boiler and check again the maximum gas pressure setting.
12 Turn the boiler off and disconnect the gauge.
Important: after the gas pressure checks and any adjustment operations, all of the test points must be sealed and replace the adjustment protection cap.
11.4
Checks
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
n
Check the modulation operator coil
1
2
Remove the front panel of the case.
Disconnect the connectors D (Fig. 50) from the modulating operator and measure the electrical resistance of the coil. Its electrical resistance value must be approx. 114 Ω*.
n
Check the on---off operators coils
1
2
Remove the front panel of the case.
Disconnect the electrical connector E (Fig. 50).
* at ambient temperature.
Fig. 49
11.5
Removal of the gas valve
2
3
5
6
1
4
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
Remove the front panel of the case as explained in the section 2.3 of this manual.
Disconnect the connectors D and E (Fig. 50).
Turn off the gas supply and disconnect the gas isolation cock connector from the inlet port of the gas valve.
Unscrew the connectors F and remove the pipe
G
Unscrew the screws H and remove the valve.
Reassemble the valve carrying out the removal operations in reverse order.
After any service operation on the components of the gas circuit check all the connections for gas leaks.
Warning: After cleaning or replacement as detailed above, if it deemed necessary to undertake a combustion analysis, refer to the appropriate chapter Maintenance of the installation instructions manual.
Fig. 50
F
H
E D
G
24
12
Primary circuit flow switch
12.1
Function
The Primary circuit flow switch ( A in Fig. 51) function is to detect water flowrate through the primary hydraulic circuit of the boiler.
Boiler OFF
Fig. 52
B
Boiler ON n
Electrical check
It is possible to verify the general operation of the switch by measuring the electric resistance between the contacts C. and N.O. of the switch.
1 Remove the switch as explained in section 12.3.
2
3
Measure the electrical resistance between the tabs marked C. and N.O. (Fig. 53).
The contact must be normally open.
Operate the switch by hand and verify that the contact is now closed.
N.O.
C
A
I
Fig. 51
This hydraulic/membrane operated electrical micro--switch device will control the functioning of the ignition control circuit, providing there is an adequate quantity and flow of water in the primary circuit. Any failure of the pump or obstructions in the primary circuit, whilst in either c.h. or d.h.w. modes, will not allow the device to operate.
This device is connected to the electronic control p.c.b.
and if, after the pump operates, it does not activate within 20 seconds the control board will indicate that a fault condition (see section 10.4 of this manual) has occurred.
12.2
Checks
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
n
Mechanical function
1
2
3
Remove the front panel of the case.
Start and stop the boiler either in d.h.w. or c.h.
mode.
Looking through the switch box verify the position of the shaft B referring to Fig. 52.
do not use
Fig. 53
12.3
Removal
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
3
4 n
Removal of the switch
1
2
Remove the front panel of the case.
Remove the fork
C (Fig. 54).
Open the box and disconnect the switch.
Re---assemble the parts in reverse order of removal. Refer to Fig. 53 for the correct wiring connectors on the switch n
1
2
Removal of the membrane
Remove the front and right hand side panels of the case, turn off the flow and return isolation valves and empty the primary circuit.
Remove the fork C that holds the micro---switch housing D (Fig. 54).
D C
Fig. 54
3 Unscrew the four screws E (see Fig. 55) open the hydraulic operator and remove the membrane F.
25
Primary circuit flow switch
H
F
G
E
1
2
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
Remove the front and left hand side panels of the case, turn off the flow and return isolation valves and empty the primary circuit.
Completely unscrew the connection K, the locknut
L (Fig. 57) and remove the expansion vessel from the top of the boiler.
Fig. 55
4 Reassemble the parts in reverse order of removal.
When assembling the membrane, ensure that its concave side faces towards the actuator plate G and the reference indicated aligns with the seat H (see
Fig. 55).
13
Expansion vessel and temperature---pressure gauge
13.1
Function
The Expansion vessel ( I in Fig. 51) function is to allow for the volume expansion of the c.h. circuit water due to the temperature rise.
1
2
13.2
Checks
Turn off the flow and return isolation valves and empty the primary circuit of the boiler.
Remove the protective cap J (Fig. 56) from the valve on the top of the expansion vessel and connect a suitable air pressure gauge.
J
B
D
K L
Fig. 57
3 Re---assemble the parts in reverse order of removal.
1
2
3
4
13.4
Removal of the temperature---pressure gauge
Remove the front and right hand side panels of the case, turn off the flow and return isolation valves and empty the primary circuit.
Remove the fork M and the probe holder spring
N (Fig. 58).
Squeeze the tabs O to release the temperature--pressure gauge P and remove it.
Re---assemble the parts in reverse order of removal.
O
N M
Fig. 56
3 Check the pre---load pressure and refer to the section Expansion vessel in the User manual and
installation instructions for the correct value.
13.3
Removal of the expansion vessel
If there is at least 400 mm clearance above the boiler and the rear exit flue can be easily removed, the expansion vessel can be changed without removing the boiler.
Fig. 58
P
26
14
D.h.w. flow switch, filter and flow limiter
14.1
Function
The d.h.w. flow switch A in Fig. 59 is a device that generates an electrical signal when hot water is drawn.
14.2
Nomenclature and location of parts
(Fig. 61)
1 Flow switch sensor
4
5
2
3
Body
O---ring
Spring
Magnetic ring
6
7
8
Float
Threaded ring
Flow limiter (M96.28SM/..., M96.32SM/... optional accessory)
9 Filter
10 Spring seat
2
1
A
Fig. 59
When the flow rate through the d.h.w. circuit reaches about 2,5 litres/min’, the float 6 (Fig. 61) is drawn towards the right.
The resulting magnetic field of ring 5 increases and reaches the flow switch sensor 1.
The sensor generates an electrical signal that switches the boiler d.h.w operation ON.
The state of the sensor is also indicated by means of the lamp B placed on the sensor body.
Fig. 60
C
B
3
4
8
7
6
5
9
Fig. 61
14.3
Checks
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
n
Flow switch sensor operation
1 Remove the front panel of the case.
2 Switch on the boiler and open a d.h.w. tap. The lamp B (Fig. 60) placed on the sensor body is switched on when the flow rate reaches about 2,5 litres/min’.
1
2
14.4
Removal of the f
low switch sensor
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
Remove the front panel of the case.
Disconnect the connector
C (Fig. 60) and remove the sensor by delicately livering downwards with a screwdriver.
27
D.h.w. flow switch, filter and flow limiter
1
2
3
4
5
14.5
Removal of the flow switch group and d.h.w. circuit filter
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
Remove the front panel of the case and empty the d.h.w. circuit.
Remove the flow switch sensor (see section
14.4).
Unscrew the body 2(Fig. 61) and extract the flow switch group.
To remove the filter from the flow switch group separate the filter 9 from the threaded ring
(Fig. 61) by levering it.
Reassemble the parts following the removing sequence in reverse order.
14.6
Flow limiter
The M96.24SM/... model is factory fitted with a 10 litre/ min. flow limiter.
If on the M96.28SM/... and M96.32SM/... model the flow rate of the d.h.w. circuit is too high, it is possible to limit it by installing a flow limiter. The following sizes are available:
Nominal flow rate (litres/min)
10
12
14
Colour
Yellow
Brown
Pink
2
3
To install the threaded ring with the flow limiter:
1 Remove the flow switch group as explained in the section 14.5.
4
Remove the filter from the flow switch group.
Unscrew the threaded ring 7 (Fig. 61) and remove it from the body 2.
Reassemble the group following the above sequence in reverse order.
28
15
Temperature probe
15.1
Function
The Temperature probe has the function of converting the temperature of the water in the hydraulic circuit where it is installed into an electrical signal (resistance).
The relation between temperature and electrical resistance is stated in Fig. 62.
Ω
9000
8500
8000
7500
7000
6500
6000
5500
5000
4500
4000
3500
3000
2500
2000
1500
1000
500
12500
12000
11500
11000
10500
10000
9500
20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 ˚C
Fig. 62
On the boiler there are two Temperature probes. One on the output of the primary heat exchanger (c.h. Temperature probe)
A in Fig. 63 and Fig. 64; one on the output of the d.h.w. heat exchanger (d.h.w. Temperature probe)
B in Fig. 63 and Fig. 64.
15.2
Checks
n
Temperature---resistance relationship
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
Disconnect the cable from the Temperature probe.
Measure the temperature of the brass group where the
Temperature probe is located and check the electrical resistance according to the graph in Fig. 62.
1
2
3
4
15.3
Removal
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
To remove the Temperature probes remove the front panel of the case.
To remove the c.h. Temperature probe empty the primary circuit of the boiler.
To remove the d.h.w. Temperature probe empty the d.h.w. circuit of the boiler.
Remove the electric connector of the Temperature probe and unscrew it.
Reassemble the Temperature probe carrying out the removal operations in reverse order.
A
B
Fig. 64
A
Fig. 63 c.h.
return c.h.
flow d.h.w.
inlet d.h.w.
outlet
B
29
16
By---pass valve
16.1
Function
The By---pass valve A in Fig. 65 is located between the c.h. water flow and return and its function is that of guaranteeing a minimum flow across the primary heat exchanger if the circulation across the c.h. system is completely closed.
The By---pass valve is fitted on the rear side of the diverter group.
1
2
3
4
16.2
Removal
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
Remove all the case panels.
Empty the primary circuit of the boiler.
Remove the diverter group as described in the section 9.4 of this manual.
Unscrew the connector B and remove the by--pass valve C (Fig. 66).
B
C
Fig. 65
A
Fig. 66
5 Reassemble the by---pass valve as illustrated in
Fig. 66 reversing the order of removal.
30
17
Fan, venturi device and
Air pressure switch
17.1
Function
The function of the Fan
A (Fig. 67 and Fig. 68) is to force the products of combustion through the condensing heat exchanger to the outside air via the flue system.
The Fan is supplied by the full sequence ignition device at the beginning of the ignition cycle.
Its correct functioning is controlled by means of a system incorporating a built in venturi device ( B in Fig. 73) and an Air pressure switch C (Fig. 67 and Fig. 68) .
A D C
A
C
Fig. 67
17.2
Checks
n
Check of the fan
1
2
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
Remove all the case panels and the sealed chamber lid.
Disconnect the connectors
D (Fig. 68) and measure the electrical resistance of the motor that has to be about:
43 Ω --- M96.24SM/...
25 Ω --- M96.28SM/... M96.32SM/...
(at ambient temperature).
Fig. 68 n
Check of the Air pressure switch operation
1
2
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
Remove all the case panels and the sealed chamber lid.
Disconnect the wires and check the electrical resistance between the connections of the Air pressure switch.
Refer to the Fig. 69 in accordance with the type of air pressure switch used.
Between COM or 3 and N.O. or 2 the contact must be open.
3
4
Between COM or 3 and N.C. or 1 the contact must be closed (electrical resistance zero).
Connect the grey wire (COM or 3)
Run the boiler (the Fan must run) and check the the electric resistance between COM or 3 and
N.O. or 2. Between COM or 3 and N.O. or “2 the contact must be closed (electrical resistance zero).
COM
”L” connection
N.O.
N.C.
”H” connection
Fig. 69 n
Check of the venturi device
This test must be carried out with the sealed chamber closed
31
1
2
Fan and Air pressure switch
Remove the caps of the pressure test points located on the top of the boiler and connect a differential pressure gauge (Fig. 70).
Switch on the boiler.
D E C
F G
Fig. 71
5
6
Remove the Fan by sliding it towards left (se the arrow in Fig. 71).
Assemble the fan carrying out the removal operations in reverse sequence.
Warning: Re--assembling the fan ensure that the hooks around the inlet port of the fan hung correctly on the flue hood.
Warning: to correctly connect the venturi device to the Air pressure switch, refer to Fig. 72.
Fig. 70
3 Compare the value on the gauge with the following minimum values:
80 Pa (0,8 mbar) --- M96.24SM/...
110 Pa (1,1 mbar) --- M96.28SM/..., and
M96.32SM/...
1
2
3
4
17.3
Removal of the Fan
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
Remove all the case panels, the sealed chamber lid and the combustion chamber lid.
Disconnect the connectors
D and the earth connection E (Fig. 68).
Disconnect the pipe which connect the venturi device to the Air pressure switch.
Unscrew the screw F and remove the bracket G
(Fig. 71).
--+
Fig. 72
Warning: After cleaning or replacement as detailed above, if it deemed necessary to undertake a combustion analysis, refer to the appropriate chapter Maintenance of the installation instructions manual.
1
2
17.4
Inspection and removal of the venturi device
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
Remove the fan (section 17.3).
Remove the venturi device by unscrewing the screw
H.
32
3
4
Inspect the venturi device B and the connection pipe I. Ensure they are clean.
Re---assemble the parts in reverse order of removal.
Warning: After cleaning or replacement as detailed above, if it deemed necessary to undertake a combustion analysis, refer to the appropriate chapter Maintenance of the installation instructions manual.
B
Fig. 73
H
I
Fan and Air pressure switch
17.5
Removal of the Air pressure switch
3
4
1
2
5
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
Remove all the case panels and the sealed chamber lid.
Disconnect the wires from the Air pressure switch.
Remove the pipe from the Air pressure switch.
Unscrew the screws which hold the Air pressure switch to the frame.
Assemble the Air pressure switch carrying out the removal operations in reverse sequence.
Warning: to correctly connect the Air pressure switch, refer to Fig. 72 and Fig. 69a or Fig. 69b for the correct wiring.
Warning: After cleaning or replacement as detailed above, if it deemed necessary to undertake a combustion analysis, refer to the appropriate chapter
Maintenance of the installation instructions manual.
33
18
Ignition and detection electrodes
18.1
Function
Three electrodes are fitted on the burner. Two of them are the ignition electrodes and are fitted near the front part of the burner. The ignition sparks take place between their metallic edges over the central ramp of the burner during the ignition sequence.
The third electrode is the detection electrode and it detects the presence of the flame.
Ignition
Detection
Male
Female
3 Check the integrity of the detection electrode and ensure that its metallic edge is correctly placed over the ramp of the burner.
n
Check the connection wires.
1
2
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
Remove all the case panels, the sealed chamber lid and the combustion chamber lid.
Check for the integrity of the insulation of wires which connect the electrodes to the ignition device.
1
2
3
4
5
18.3
Removal
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
Remove all the case panels, the sealed chamber lid and the combustion chamber lid.
Disconnect the electrode wires from the full sequence ignition device.
Remove the plate C (see Fig. 78 on page 35).
Remove the burner by unscrewing the four screws placed at the right and left sides of the burner.
Unscrew the screws A (Fig. 76) which hold the electrodes to the burner.
Fig. 74
18.2
Checks
n
Check the position of the electrode edges
1
2
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
Remove all the case panels, the sealed chamber lid and the combustion chamber lid.
Check for the correct distance between the metallic edges of the ignition electrodes (see
Fig. 75).
4 mm
Fig. 75
34
Ignition
A
Fig. 76
6
7
Extract the electrodes from the burner.
Assemble the electrodes carrying out the removal operation in reverse order.
Refer to Fig. 74 in order to recognise the electrodes and to correctly connect the wiring.
Note: the metallic edge of the detection electrode is longer than the one of the ignition electrodes.
Warning: After cleaning or replacement as detailed above, if it deemed necessary to undertake a combustion analysis, refer to the appropriate chapter Maintenance of the installation instructions manual.
19
Safety thermostat
19.1
Function
The safety thermostat
A in Fig. 77 and Fig. 78 is a device that senses the temperature of the primary circuit water which flows in the outlet pipe of the primary heat exchanger.
If the temperature control system of the boiler fails and the temperature of the primary circuit reaches a dangerous temperature, the safety thermostat opens the electric circuit that supplies the on---off operators of the gas valve.
Consequently, the full sequence ignition device attempts to light the burner and, at the end, locks the boiler and lights the lock---out signal lamp.
contact must be closed (electrical resistance zero
Ω).
1
2
19.3
Removal
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
Remove all the case panels and the lid of the sealed chamber.
Remove the screw B and the plate C (Fig. 78).
A
C
B
A
Fig. 78
3
4
Disconnect the wiring D (detail in Fig. 79).
Remove the spring
E which holds the overheat thermostat on the pipe of the primary heat exchanger and remove it.
D
Fig. 77
19.2
Checks
n
Overheat temperature value
1
2
Set the temperature control knobs to their max.
position and run the boiler in d.h.w. and c.h.
Allow the boiler to reach its maximum operating temperature (monitor the temperature gauge on the instrument panel). The boiler should maintain a temperature below that of the safety thermostat and no overheat intervention should occur.
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
n
Electrical function
1
2
3
Remove all the case panels and the lid of the sealed chamber.
Remove the screws B and the plate C (Fig. 78).
Disconnect the safety thermostat and check its electrical function. Normally (no intervention) the
E
Fig. 79
5
6
Reassemble the overheat thermostat carrying out the operations in reverse order.
Apply an adequate quantity of heat conducting compound between the pipe and the thermostat.
Warning: After cleaning or replacement as detailed above, if it deemed necessary to undertake a combustion analysis, refer to the appropriate chapter Maintenance of the installation instructions manual.
35
20
Flue temperature probe NTC
20.1
Function
The Flue temperature probe NTC A in Fig. 80 and
Fig. 81 senses the temperature of the combustion products that flow through the condensing heat exchanger.
A
B
Fig. 80
If the temperature of the combustion products circuit reaches the limit temperature, the Flue temperature probe NTC reduces the gas flow rate to the burner. The temperature of the combustion products should decrease to a safe value temperature.
In the case that the temperature of the combustion products reaches a potentially dangerous value, it stops the boiler operation. It is therefore allowed the use of plastic materials for the flue outlet pipes and bends.
The use of kits different from the original isn’t however allowed, since the flue pipes are integral parts of the boiler.
If not, the electronic control p.c.b. attempts to light the burner and, at the end, locks the boiler and lights the lock---out signal lamp.
Fig. 81
20.2
Checks
n
Overheat temperature value
1
2
Set the temperature control knobs to their max.
position and run the boiler in d.h.w. and c.h.
Allow the boiler to reach its maximum operating temperature (monitor the temperature gauge on the instrument panel). The boiler should maintain a temperature below that of the Flue temperature probe NTC and no overheat intervention should occur.
1
2
3
4
20.3
Removal
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
Remove all the case panels and the sealed chamber lid.
Disconnect the wires from the Flue temperature probe NTC.
Unscrew and remove the thermostat probe
B
(Fig. 81) from the condensing heat exchanger.
Assemble the Flue temperature probe NTC carrying out the removal operations in reverse sequence.
36
21
Condensate trap
21.1
Function
The condensate trap A in Fig. 82 and Fig. 84 allows the discharge of the condensate via the condensate drain pipe avoiding in the mean time the escape of combustion products.
A plastic ball closes the trap outlet in case that the trap is empty.
A
C
B
Fig. 83
If the drain pipe is plugged or in any case in which the condensate isn’t correctly evacuated, the condensate level in the trap rises putting in contact the electrodes thus causing the boiler lock---out.
21.2
Removal
Warning: isolate the boiler from the mains electricity supply before removing any covering or component.
5
6
Remove the front and right case panels.
Disconnect the trap from the draining pipe.
7
8
9
Using pliers, remove the spring D moving it upwards.
Remove the spring
E and lower the trap.
Disconnect the wirings from the trap.
10 Reassemble carrying out the removal operations in reverse order.
Fig. 82
The condensate trap is provided with two electrodes.
The electrode
B is connected to the ground circuit; the electrode C is connected to the flame detecting electrode (Fig. 83).
Fig. 84
A E D
37
12
13
E01---204
E01---205
14 H20---993
15 E00---684
16
17 E00---688
18 E83---086
19 E83---101
20
21
22 164---026
23 E83---127
24 E83---126
25 E83---122
26 E83---145
27 H07---112
22
Short spare parts list
Key G.C. part no.
Description
1
2
5
6
7
3
4
8
173---148
173---149
169---069
E01---156
E83---121
H20---984
H20---985
H21---048
H21---049
169 127
H08---605
E83---013
Burner (mod. M96.24SM/...,)
Burner (mod. M96.28SM/..., M96.32SM/...)
Injectors for natural gas (mod. M96.24SM/..., )
Injectors for natural gas
(mod. M96.28SM/..., ,M96.32SM/...)
Injectors for LPG (mod. M96.24SM/...)
Injectors for LPG
(mod. M96.28SM/..., ,M96.32SM/...)
Expansion vessel
Main heat exchanger (mod. M96.24SM/...)
Main heat exchanger (mod. M96.28SM/... )
Main heat exchanger (mod. M96.32SM/... )
Fan (mod. M96.24SM/...)
Fan (mod. M96.28SM/..., ,M96.32SM/...)
Gas valve
Air pressure switch 0,88---0,74 mbar
(mod. M96.24SM/..., M96.32SM/...)
Air pressure switch 1,38---1,25 mbar
(mod. M96.28SM/..., )
Safety valve
9 E83---178
10 E83---180
E83---181
11
Combustion chamber side panels
Combustion chamber rear panel
(mod. M96.24SM/...)
Combustion chamber rear panel
(mod. M96.28SM/... , M96.32SM/...)
Combustion chamber front panel
(mod. M96.24SM/...)
Combustion chamber front panel
(mod. M96.28SM/... , M96.32SM/...)
Electronic regulation p.c.b.
D.h.w. heat exchanger (M96.24SM/...)
D.h.w. heat exchanger (M96.28SM/...,
M96.32SM/...)
Pump
Primary circuit flow switch
D.h.w. flow switch
Main. flow switch membrane
Three way diverter valve (electric actuator)
Overheat thermostat
Flue temperature probe NTC
Fuse 3,15 AF
Temperature probe (main or d.h.w. circuit)
Ignition electrode (left)
Ignition electrode (right)
Detection electrode
Temperature---pressure gauge
Recuperator
1
1
1
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1
1
Q.ty Manufacturer part no.
KI1004 102
KI1004 147
Manufacturer’s reference
Polidoro
12
KI1064 505
Polidoro
14
12 BI1003 509
14
1
1
BI1172 103
BI1262 101
BI1262 102
BI1262 130
BI1406 100
BI1406 101
KI1267 103 Yamatake---Honeywell C6065
SIT 380 (alternative)
BI1376 104 Yamatake---Honeywell C6065
SIT 380 (alternative)
BI1131 100 Watts
Orkly (alternative)
BI1326 100
BI1326 107
BI1326 108
BI1406 118
CIMM 6 litres
BI1243 100 Honeywell
BI1406 119
BI1715 105 Bertelli & Partners
BI1001 101
BI1001 102
BI1262 103
BI1011 505
BI1271 101
BI1011 103
BI1101 102 Elbi
BI1172 105 ELTH --- type 261
BI1342 100
BI1295 108
BI1001 117
BI1123 101
BI1123 103
BI1123 102
BI1475 108 IMIT
BI1262 122
38
1
2
3
Short spare parts list
4
10 9
5
6
7 8
12
9
13 14
11
15 16 17
18
19 20 21 22 23 24 25 26
27
39
*1796212314*
17962.1231.4
0907 44A4 UK
Biasi UK Ltd
Newman Park, Western Way
Wednesbury, WS10 7BJ
Sales Tel No: 0121 506 1340
Sales Fax No: 0121 506 1360
Service Tel No: 0121 506 1350
Service Fax No: 0121 506 1370 www.biasi.co.uk
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Key Features
- High efficiency gas boiler
- Wall hung
- Fan flue
- Room sealed
- Service manual
