Biasi Riva Compact HE MK2 M96A.24SM/C, M96A.28SM/C, M96A.32SM/C gas boiler Service manual

Wall hung, fan flue, room sealed, high efficiency gas boiler

Service manual

RIVA COMPACT HE MK2

Models:

M96A.24SM/C

M96A.28SM/C

M96A.32SM/C

G.C. Appl. No.

47---583---17

47---583---18

47---583---19

Combi boiler

Combi boiler

Combi boiler

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

Diagrams

Wiring diagram

Circuit voltages

Fault finding

. . . . . . . . . . . . . . . . . . . .

Nomenclature

Body panels

. . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . .

Control panel . . . . . . . . . . . . . . . . . . . . . . . .

Access to the sealed chamber

Emptying the primary circuit

Emptying the d.h.w. circuit

. . . . . . . . .

. . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . .

Functional flow diagrams . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . .

9

9.1

9.2

9.3

9.4

9.5

8

8.1

8.2

8.3

6

6.1

6.2

6.3

5

5.1

5.2

5.3

7

7.1

7.2

Primary heat exchanger

Function

Removal

Cleaning

Condensing heat exchanger

Function

Removal

Cleaning

D.h.w. heat exchanger

Function

Removal

Pump

. . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Function

Checks

Removal

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Three way diverter valve . . . . . . . . . . . . .

Function

Checks

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Removal of the electric actuator

Removal of the tree way diverter valve

Removal of the diverter group

. . . . . . . .

. .

. . . . . . . . . .

10 Electronic control/ignition p.c.b.

. . . . . .

. . . . . .

18

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 21

10.6

Useful output setting

10.7

operation mode

. . . . . . . . . . . . . . . . . .

Reignition frequency setting . . . . . . . . . . .

10.8

Ignition gas pressure adjustment

10.9

Setting the tree way diverter valve

. . . . . . .

10.10 Checks

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. .

23

24

10.11 Removal of the electronic control p.c.b

24

18

18

19

20

21

22

22

10.12 Thermal control in the ” ” mode 26

10.13 Thermal control in the ” ” mode

10.14 Ignition and control sequence

. . . . . .

. . . . . . . . . .

26

27

11

11

11

11

13

13

13

9

9

9

9

16

16

16

16

17

17

14

14

14

14

4

4

5

6

7

2

2

3

2

2

3

3

1

1

1

11 Modulating gas valve . . . . . . . . . . . . . . . .

11.1

Function

11.2

11.4

Checks

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Nomenclature of the parts

11.3

Adjustment

. . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

11.5

Removal of the on---off operators coils

11.6

Removal of the gas valve

. .

. . . . . . . . . . . . . .

12 Primary circuit pressure switch

12.1

Function

12.2

Checks

12.3

Removal

. . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

13 Expansion vessel and temperature--pressure gauge . . . . . . . .

13.1

Function

13.2

Checks

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

13.3

Removal of the expansion vessel . . . . . . .

13.4

Removal of the temperature---pressure gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

31

14

14.1

14.2

14.3

14.4

D.h.w. flow switch, filter and flow limiter 32

Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Nomenclature and location of parts

Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Removal of the sensor . . . . . . . . . . . . . . . .

14.5

Removal of the flow switch group

. . . . .

and d.h.w. circuit filter

14.6

Flow limiter

. . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . .

32

32

32

32

32

33

30

30

30

31

15 Temperature probe . . . . . . . . . . . . . . . . . .

34

15.1

Function

15.2

Checks

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

34

34

15.3

Removal of the c.h. Temperature probe .

34

15.4

Removal of the d.h.w.Temperature probe 34

16 By--pass valve

16.1

Function

16.2

Removal

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

36

36

36

17 Fan and Air pressure sensor . . . . . . . . .

17.1

Function

17.2

Checks

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

17.3

Removal of the Fan . . . . . . . . . . . . . . . . . . .

17.4

Removal of the Air pressure sensor . . . . .

18 Ignition and detection electrodes

18.1

Function

18.2

Checks

18.3

Removal

. . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

39

39

39

39

37

37

37

38

38

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

. . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

21 Condensate trap

21.1

Function

21.2

Removal

. . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

22 Short spare parts list . . . . . . . . . . . . . . . .

44

44

44

46

42

42

42

42

41

41

41

41

28

28

28

28

29

29

29

30

30

30

30

1

Overall information

1.1

Overall View

Air pressure sensor

Flue temperature probe NTC

Fan

Condensing heat exchanger

Expansion vessel

Main heat exchanger

Combustion chamber

Burner

Ignition electrodes

Detection electrode

Primary circuit pressure switch

Diverter valve

D.h.w. temp.

probe

Gas valve

Control panel

1.2

Hydraulic diagram

Central heating (c.h.) operation

Safety thermostat

C.h. temp.

probe

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.

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.

B

D

C

Fig. 3 --- bottom view of the boiler

B

2.3

Control panel


3

4

1

2

To gain access to the parts located inside the control panel proceed as follows:

Remove the front panel of the case

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.

2

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

F

E

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).

H

J

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.

Fig. 5

2.4

Access to the sealed chamber

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 bn gnye bu

3 2

1 bu bk bn

1 M

~

2 rd bk wh

3

Fan

M

~ bn bu gnye

M

~ bu bn gnye

Primary circuit pressure switch bk bk

2

Air pressure sensor

1

P rd ye gy

3

Ignition electrodes

Flame detection electrode

4

bn bn bu bk bu

*bk *bn *bu wh rd bk bn bu bn bu gnye gy gy bn bu bn bu bu bk bk rd rd wh wh rd rd ye gy wh bu bk bk bu bu bu bu rd gy ye gn wh bk rd rd t rd bu wh

D.h.w. temperature probe NTC

D.h.w. flow switch

* = alternative bu = blue bk = black wh = white rd = red gy = grey gn = green ye = yellow vt = violet og = orange gnye = green/yellow gy ye bu bn bu gnye

1

3

4 bk bk

Modulating gas valve

Safety thermostat wh wh t t bu bu

Flue probe NTC

C.h. temperature probe NTC rd bk wh gn

Time switch

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


J3--- 4

J3--- 1

Pump

J3--- 2

J2--- 5

Full sequence ignition device

J2--- 4



J3--- 5

J3--- 3


J3--- 4

J3--- 1

Pump

J3--- 2

J2--- 5


J2--- 4



J3--- 5

J3--- 3


J3--- 4

J3--- 1

Pump

J3--- 2

J2--- 5


J2--- 4

J1--- 2

N

J1--- 2

N

J1--- 2

N

5

Diagrams

3.3

Circuit voltages

Electrical voltages with burner on

Pump

Supply network

3 way diverter valve

Modulating

Gas valve

Fan during c.h. or d.h.w. operation only during c.h. operation only during

d.h.w. operation

6

Safety thermostat

Air pressure sensor

--- (8)

--- (7)

--- (4)

--- (3)

--- (2)

--- (1) ge gau ssure e alv tyv l vesse ion ans s ctor

TC eN prob t ode e or lectr trod sens ermosta ctione elec ssure or)

) h perat rators itc sw b.) go obe ve val ass ope p.c.

atin e rob p.p

em p.pr

em uitt irc h sure off b.

odul nic itc sw tro pres n--p.c.

r ilte uit irc ve(m ve(o ttings valve lec (E low nic w.f

es ctro rter erse val val nc w.f

nc w.t

- -p tyth ition pre

Ign

Air

Fan

Dete

Safe

Dive

D.h.

Boil

Gas

Gas

Mai

D.h.

Mai

D.h.

By-

Ele

Fus

Flue

Inje

Exp

Safe

Pre

Pump anger xch ate w.he

D.h.

uit irc w.c

D.h.

uit circ C.h.

trap and ipe np drai te nsa Conde s pipe Flue ne yli suppl Gas e lin upply ers Pow d pre lam nal sig out k--Loc

ON OFF

7

--- (8)

--- (7)

--- (4)

--- (3)

--- (2)

--- (1) ge gau ssure e alv tyv l vesse ion s ctor ans or e ode t

TC sens trod lectr eN prob tyth ssure elec ctione ermosta or)

) h perat rators itc sw b.) go obe ve val ass e rob p.p

em ope p.c.

p.pr

atin em uitt irc r ilte sure pres uit irc odul ve(m h off n--ve(o ttings b.

nic itc sw p.c.

tro lec (E nic low w.f

es ctro valve rter erse val val nc w.f

nc w.t

- -p

Mai

Gas

D.h.

Fus

Ele

By-

D.h.

Mai

D.h.

Gas

Boil

Dive pre ition

Air

Ign

Dete

Safe

Fan

Flue

Exp

Inje

Safe

Pre

Pump anger xch ate w.he

D.h.

uit irc w.c

D.h.

uit circ C.h.

trap and 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. 1 has the function of transferring heat produced from combustion of the gas to the water circulating in it.

7 Remove the clip I and the safety thermostat J and the c.h. temperature probe

K. It is not necessary to disconnect it from the wiring.

F

A

H

G

C

B

J

I

K

Fig. 1

The hydraulic circuit is composed of 8 elliptical pipes connected in parallel (Fig. 2).

Fig. 2

1

2

3

4

5

6

5.2

Removal


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 (Fig. 3).

Remove the screws

D and the plate E.

Remove the clip

F

Loosen the connection G and slightly move the pipe H upwards.

C

M

E

D

L

O

Fig. 3

8 Loosen the connection L and move the pipe M downwards freeing it from the connection of the primary het exchanger.

9 Remove the clip

N

10 Loosen the connection

O

11 free the pipe P from the connection of the condensing heat exchanger; lift and and rotate it towards right.

12 Remove the heat exchanger by sliding it forwards.

13 Reassemble the boiler carrying out the removal operations in reverse order.

Fit the clip

I with the arrow pointing upwards as illustrated in Fig. 3.

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.

9

N

P

Primary heat exchanger

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.

10

6

Condensing heat exchanger

6.1

Function

The return water flows through the condensing heat exchanger A in Fig. 1 and Fig. 2.

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

D

B

C

Fig. 1

6.2

Removal


5

6

7

8

2

3

4

1

9



Remove the fan D in Fig. 2 (see section 17.3).

Disconect the connectors of the flue temperature probe NTC

E

Remove the clip

F .

Completely loosen the connection G and slightly move the pipe

H upwards.

Remove the clip I.

Loosen the connection

J

Free the pipe

K from the connection of the condensing heat exchanger; lift and and rotate it towards right.

10 Using pliers, remove the spring L moving it to wards right and disconnect the rubber pipe

M.

11 Rotate the exchanger as indicated by the arrow and remove it towards the front of the boiler.

J

Fig. 2

12 Reassemble the exchanger carrying out the removal operations in reverse order.

Warning: to lubricate the O--ring gaskets exclusively use a silicone base grease compatible to be in contact with foods and approved by the local water Authorities.

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.

1

2

3

6.3

Cleaning

Using pliers, remove the spring

L moving it to wards right and disconnect the rubber pipe

M

(Fig. 3).

Unscrewing the screws N (Fig. 3).

Remove the condensing heat exchange lid

O

(Fig. 3) moving torwards the front of the boiler.

If there are deposits of soot or dirt on the exchanger lid, clean with a brush or non---metallic bristle brush.

11

E

F

H

A

I

L

M

G

K

Condensing heat exchanger

In any case, avoid any actions that can damage the protective varnish with which the lid has been covered.

4 Reassemble the exchanger carrying out the removal operations in reverse order.




N

L

O M

Fig. 3

12

7

D.h.w. heat exchanger

7.1

Function

The d.h.w heat exchanger

A in Fig. 1 and Fig. 4 allows the instantaneous transfer of heat from the primary hydraulic circuit to the water destined for d.h.w use.

4

5

Remove the clip C and remove the primary circuit pressure switch

D by lifting it upwards. It is not necessary to disconnect it from the wiring.

Remove the clip

E and remove the electric actuator F by pulling it. It is not necessary to disconnect it from the wiring.

A

D

C

B

E

F

Fig. 3

6 Completely unscrew the two Allen key screws

G

(Fig. 4) which hold the exchanger to the plastic groups.

A

Fig. 1

The schematic structure is shown in Fig. 2.

Primary hydraulic circuit

Domestic hot water circuit

Fig. 2

1

2

3

7.2

Removal


Remove the front and right hand side panels of the case.

Empty the primary circuit and the d.h.w circuit of the boiler.

Remove the pump B in Fig. 3 (see section 8.3).

Fig. 5

G

Fig. 4

7 Move the exchanger towards the rear of the boiler and extract it.

Reassemble the d.h.w. heat exchanger carrying out the removal operations in the reverse order.


Attention. When reassembling the exchanger be sure to put the off center location/securing pin indicated in Fig. 5 towards the left side of the boiler.

13

8

Pump

8.1

Function

The pump A in Fig. 1 and Fig. 3 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).

A

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.

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

4

5

6

2

3

8.3

Removal




Extract and lower the control panel.

Remove the clip

C (Fig. 2).

Loosen the connection

D (Fig. 2).

free the pipe E (Fig. 2) from the connection of the condensing heat exchanger; lift and and rotate it towards right.

C

E

Fig. 1

8.2

Checks


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. 3).

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.

14

Fig. 2

7 Disconnect the connector B (Fig. 3).

D

B

A

Fig. 3

G

F

Pump

8

9

Remove the locking plate F (Fig. 3).

Unscrew the two screws

G that hold the pump on the frame and remove the pump.


Reassemble the pump carrying out the removal operations in the reverse order. When reassembling the pump, check the correct location of the O---ring gasket in the inlet port of the pump that seals the connection between the pump and the return water group.

15

9


9.1

Function

The diverter valve

A (Fig. 1) has the function of modifying the hydraulic circuit of the boiler by means of an electric command given by the electronic control p.c.b.

in order to send the water that exits the primary heat exchanger towards the c.h. system or towards the d.h.w.

heat exchanger.

B

A

Spindle B visible

Fig. 2 --- D.h.w. mode

B

9,4 Kohm

Open circuit rd = red wh = white bk = black bu = blue bn = brown

* = alternative

Spindle B not visible

Fig. 1

9.2

Checks

n

Check the electrical continuity

Fig. 2 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. 3 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.

Open circuit

9,4 Kohm rd = red wh = white bk = black bu = blue bn = brown

* = alternative

Fig. 3 --- C.h. mode

1

2

3

9.3

Removal of the electric actuator


Remove the front case panel.

Disconnect the connectors C (Fig. 4).

Remove the fixing spring D and remove the actuator B.

Reassemble the actuator carrying out the removal operations in the reverse order.

When reassembling the actuator, refer to Fig. 2 or to the wiring diagram in section 9.2 for the correct wiring connection.

16

D

C

B

Three way diverter valve

3

4

1

2

9.5

Removal of the diverter group

Remove the front and both side case panels.


Remove the electric actuator (see section 9.3).

Remove the fixing spring H (Fig. 6) and remove the primary circuit pressure switch

I.

Fig. 4

3

4

5

1

2

9.4

Removal of the tree way diverter valve

Remove the front and both side case panels.


Remove the electric actuator (see section 9.3).

Remove the fixing spring

E (Fig. 5)

Remove the tree way diverter valve

F by levering with a screwdriver in as shown in Fig. 5.

I

H

M

L

K

N

Fig. 6

5 Disconnect d.h.w. temperature probe, respectively J (Fig. 7).

F

G

J

E

Fig. 5

Reassemble the tree way diverter valve carrying out the removal operations in the reverse order.


Attention. When reassembling the tree way diverter valve be sure that the tree way diverter is correctly oriented by matching the reference G with the notch of the water group Fig. 5

Fig. 7

6 Unscrew the connector K (Fig. 6), the c.h. flow connector and the d.h.w. outlet connector.

7

8

9

Remove the d.h.w. heat exchanger (see section

7.2).

Remove the fork L and move away the pipe M

(Fig. 6).

Unscrew the screws

N and remove the diverter group (Fig. 6).

10 Reassemble the diverter group carrying out the removal operations in the reverse order.


17

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


Air pressure sensor


Safety thermostat

Flame detection electrode

Room thermostat (if fitted)

Time switch

Fig. 1

18

Outlet command

Pump


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. 1).

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 sensor.

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

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 sensor can temporarily stop the ignition of the burner but allow its ignition when the cause of the intervention has stopped.

Fig. 27 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. 2).

Some of these devices are directly accessible by the user (function control, temperature adjustment poten-

tiometers etc.) others are accessible by removing the service panel or the control panel lid.

1

2

3 4 5 6

14

13

Electronic control/ignition 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. 3), the signal coming from the c.h. temperature probe is compared to the signal given by the control panel through the adjustment made by the user (knob ). The result of such a comparison operates the modulation of the gas valve, consequently changing the useful output of the boiler.

12 11 10 9 8 7

Fig. 2

4

5

6

7

8

1

2

3 x1 connector x6 connector x7 connector x4 connector x2 connector x15 connector x11 connector

Lock---out signal lamp

9 Boiler reset button

10 Function control / C.h. temperature adjustment

11 D.h.w. temperature adjustment

12 Appliance operation lights

13 x8 connector

14 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 (10 and

11 in Fig. 2) of the electronic control p.c.b.

Fig. 3

When the boiler functions in d.h.w. (Fig. 4), 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 ).

19


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

With the boiler switched ON ( or ) all the lamps

(12 in Fig. 2) are activated.

The following table gives the relationship between each of the possible lamp combinations and their meaning.

75

˚C

Fig. 4

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 10.12 and 10.13.

10.4

Operation lights

The Electronic control/ignition p.c.b. is provided with three lamps (L.E.D. indicators) 12 in Fig. 2 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.

20

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 low c.h. pressure)

Faulty primary circuit

(absence of flow)

Faulty air pressure sensor

Lack of burner ignition (no ignition signal from the full seqence ignition device)

Safety thermostat lock out

Flue temperature probe NTC lock out

Flame detection error

Other faults

Lack of power supply or fauly electronic control 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. 5).

During the function modes setting, the boiler does not operate.


Where:

Lamp OFF

M96A.24SM/...

1 flash

Lamp ON

Fig. 8

At this step it is possible to visualize the current setting by keeping the reset button D pressed for more than 5 seconds. The lamps F will flash a number of times corresponding to the setting Fig. 9 (once for

M96A.24SM/... , four times for M96A.28SM/... and seven times for M96A.32SM/...).

M96A.28SM/...

4 flashes

M96A.32SM/...

7 flashes

2

3

Fig. 5

F

To set the useful output proceed as follows:

1 Remove the front panel of the case.

4

Fig. 6

5

B

A

D E

10.6

Useful output setting

Take off the lid of the sealed chamber.

Switch on the appliance at the mains isolating spur.

Turn the boiler OFF positioning the function selector A as indicated in Fig. 6.

F B A D E

Disconnect the electrical connectors C of the C.h.

temperature probe NTC in Fig. 7

B

Fig. 9

9 To change the setting turn the knob B on a position corresponding to the boiler models (Fig. 9).

By turning the knob B, the lock---out signal lamp

E blinks quickly (2 per seconds) indicating that the setting has changed and must be memorised.

10 To memorize the setting keep pressed the reset button D for about 5 seconds until the lights F briefly blinks simultaneously.

11 Press the reset button D once until the lamps F give the indication as in Fig. 10 (useful output, second step).

Where:

Lamp OFF

Lamp ON

Fig. 10

At this step it is possible to visualize the current setting by keeping the reset button D pressed for more than 5 seconds. The lamps F will flash a number of times corresponding to the setting Fig. 11 (once for

M96A.24SM/..., M96A.28SM/... and M96A.32SM/...).

M96A.24SM/...

M96A.28SM/...

M96A.32SM/...

1 flash

C

Fig. 7

6

7

8

Keep pressed the reset button D for about 10 seconds until the lock---out signal lamp E blinks.

Connect the the elctrical connectors C of the C.h.

temperature probe NTC in Fig. 7

The lamps F should give the indication as in Fig. 8

(useful output, first step). If not, press the reset button repeatedly to obtain it.

B

Fig. 11

12 To change the setting turn the knob B on a position corresponding to the boiler model (Fig. 11).



21



14 To reset the boiler to the normal operation turn it

OFF and ON by the function selector knob A.

10.7

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. 12.

any case, the boiler automatically resets to its normal operation after 10 minutes.

Factory setting = 3minutes

1

2

3

4

10.8

Ignition gas pressure adjustment

Turn the boiler OFF.

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. 15 (M96A.24SM/...,

M96A.28SM/..., M96A.32SM/...) 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. 12

F

2

3

B A D E


The lamps F should give the indication as in

Fig. 13 (reignition frequency). If not, press the reset button repeatedly to obtain it.

Where:

Lamp OFF

Lamp ON

Fig. 13

At this step it is possible to visualize the current setting by keeping the reset button D pressed for more than 5 seconds. The lamps F will flash a number of times corresponding to the setting (Fig. 14).

4 To change the setting turn the knob B on a position corresponding to the desired delay.



4

4

1 1/2

0

1

2

3

3

5

5 1/2

6

7

7

8 1/2

B

Delay (minutes)

Setting No.

Fig. 14

5

6

To memorize the setting keep pressed the reset button D for about 5 seconds until the lights F briefly blinks simultaneously.

To reset the boiler to the normal operation turn it

OFF and ON by the function selector knob A. In

22

Fig. 15

F

5

6

B A D E


The lamps F should give the indication as in

Fig. 16. If not, press the reset button repeatedly to obtain it.

Where:

Lamp OFF

Lamp ON

Fig. 16

7 Keep pressed the reset button D for about 5 seconds until the lock---out signal lamp E is switched

OFF.

The boiler runs in c.h. mode and the lamps F give the indication as in Fig. 17.

Where: Lamp OFF

Flashing lamp, alone or simultaneously with an other lamp.

Fig. 17

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. 18


F B A D E

Fig. 18

11 Keep pressed the reset button D for about 10 seconds until the lock---out signal lamp E blinks.

12 Press the reset button D repeatedly (4 times) until the lamps F give the indication as in Fig. 19 (ignition pressure adjustment mode).

Where:

Lamp OFF

Lamp ON

Fig. 19

13 Turn the knob B to the minimum (fully counterclockwise) and then on the position corresponding to the position obtained on step 8.


E blinks quickly (2 per second) indicating that the setting has changed and must be memorised.



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.

10.9

Setting the tree way diverter valve operation mode

When replacing the Electronic control/ignition p.c.b., it must be set for the correct operation of the tree way diverter valve.

Note: the Electronic control/ignition p.c.b. spare part is fattory set on mode 1.

For all the models covered by this manual:

1 Turn the boiler ON positioning the function selector knob A as indicated in Fig. 20.

2 Turn knob B as indicated in Fig. 20.

F B A D E

Fig. 20

3

4


Press the reset button D repeatedly (3 times) until the lamps F give the indication as in Fig. 21 (setting the tree way diverter valve mode operation).

Where:

Lamp OFF

Lamp ON

Fig. 21

At this step it is possible to visualize the current setting by keeping the reset button D pressed for more than 5 seconds. The lamps F will flash a number of times corresponding to the setting (Fig. 22).

5 Change the setting by turning the knob B on the position corresponding to the desired setting

(Fig. 22).




4

M96A.24SM/...

M96A.28SM/...

M96A.32SM/...

7 flashes

1 7

B

Setting No.

Fig. 22

At this step it is possible to visualize the current setting by keeping the reset button D pressed for more than 5 seconds. The lamps F will flash a number of times corresponding to the setting of Fig. 22 that must be seven times.


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.

23


10.10

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 14

(Fig. 2) 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 positive pressure test point of the Fan pressure connection devise.

After opening it the burner must turn off.

Fig. 23

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. 24) 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. 24).

10.11

Removal of the electronic control 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. 2) delicately flex the hook present on one side of each socket.

To disconnet the connectors x4 and x2 (4 and 5 in Fig. 2) 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 arrows in Fig. 23.

24

A

A

B

C

Fig. 24

Attention

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 but-


ton by pressing and releasing it.



25


10.12

Thermal control in the ” ” mode

Switch in the

See functioning with the function control in the mode

(sec. 10.13)

YES function mode

Taking water from the domestic hot water circuit?

NO

YES

Is primary circuit temperature higher than that selected?

NO

NO

Circulator off

Operates motorised valve

Ignition device off

Fig. 25

10.13

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. 26

26


10.14

Ignition and control sequence

YES

Ignition request lock memorised?

NO

NO

Air pressure sensor at rest?

YES starts fan

NO

NO

Air pressure sensor at work?

NO presence of flame?


YES starts ignition discharges opens gas valve beginning of ignition period

YES

YES beginning of wait period 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


NO

NO safety thermostat or flue temperature probe lock out?

YES

Fig. 27

27

11

Modulating gas valve

11.1

Function

The Modulating gas valve A in Fig. 1 controls the gas inflow to the boiler burner.

7

8

3

2

1

A

Fig. 1

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.

7

8

5

6

3

4

1

2

11.2

Nomenclature of the parts (Fig. 2)

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

6 4 5

Fig. 2

11.3

Adjustment

For the pressure values refer to the Technical data section of the User manual and Installation instructions

1

2

3

4



Open the gas valve inlet pressure test point (6 in

Fig. 2) 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. 2) and connect the gauge;

C

B

Fig. 3

28

5

6

7

8

9

Remove the protection cap B (Fig. 3) from the mechanical pressure adjustment components levering with a flat screwdriver in the slots

C.

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. 2) 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. 2).

Start the boiler and rotate the minimum gas pressure adjustment (1 in Fig. 2) 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


n

Check the modulation operator coil


2 Disconnect the connectors D (Fig. 5) from the modulating operator and measure the electrical resistance of the coil. Its electrical resistance value must be approx. 80 Ω*.

2

3 n

Check the on---off operators coils


Disconnect the electrical connector E (Fig. 5).

Measure the electrical resistance between the connector pins of the on---off operators as illustrated in Fig. 4.

Upper on---off operator approx. 6 400 Ω*

Lower on---off operator approx. 920 Ω*

* at ambient temperature.

Fig. 4

11.5

Removal of the

on---off operators coils


1

2

3

4

Modulating gas valve


Disconnect the connector E (Fig. 5).

Unscrew the screw F and remove on---off operator coils.

Reassemble the coils carrying out the removal operations in reverse order.

G

I

H

D

F

E

J

Fig. 5

11.6

Removal of the gas valve

2

3

5

6

7

1

4


Remove the front panel of the case as explained in the section 2.3 of this manual.

Disconnect the connectors

D and E (Fig. 5).

Turn off the gas supply and disconnect the gas isolation cock connector from the inlet port of the gas valve.

Unscrew the connectors G and remove the pipe

H.

Remove the rubber pipe

I.

Unscrew the screws J 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.


29

12


12.1

Function

The Primary circuit pressure switch ( A in Fig. 1) function is to check the presence of water in the primary hydraulic circuit and that the pressure is above the minimun.

A

N.O.

C

Fig. 2

1

2

3

12.3

Removal


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 fixing spring

B (Fig. 3) and remove the primary circuit pressure switch

A.


C (Fig. 3).

C

A

B

D

Fig. 1

This device is connected to the electronic control p.c.b.

and if, it does not activate the control board will indicate that a fault condition (see section 10.4 of this manual) has occurred.

12.2

Checks


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 Measure the electrical resistance between the tabs marked C. and N.O. (Fig. 2).

The contact must close (resistance zero) with c.h.

pressure of 0,35 bar or higher.

30

Fig. 3

4 Reassemble the primary circuit pressure switch in reverse order of removal.


13

Expansion vessel and temperature---pressure gauge

13.1

Function

The Expansion vessel ( D in Fig. 1) function is to allow for the volume expansion of the c.h. circuit water due to the temperature rise.

1

13.2

Checks

Turn off the flow and return isolation valves and empty the primary circuit of the boiler.

2 Remove the protective cap E (Fig. 4) from the valve on the top of the expansion vessel and connect a suitable air pressure gauge.

Primary circuit pressure switch

G

F

E

Fig. 4 Rear view of the boiler

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.

1

2


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 F, the locknut G (Fig. 5) and remove the expansion vessel from the top of the boiler.

I

H

J

Fig. 6

Fig. 5

3 Re---assemble the parts in reverse order of removal.

1

13.4

Removal of the temperature---pressure gauge

2

3

4

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

H and the probe holder spring I

(Fig. 6).

Squeeze the tabs J to release the temperature--pressure gauge

K and remove it.

Re---assemble the parts in reverse order of removal.

K

31

14

D.h.w. flow switch, filter and flow limiter

14.1

Function

The d.h.w. flow switch A in Fig. 1 is a device that generates an electrical signal when hot water is drawn.

6

7

8

4

5

Body

Float

Filter

Sensor holder spring

Sensor

2

1

3

Fig. 1

When the flow rate through the d.h.w. circuit reaches about 2,5 litres/min’, the float 5 (Fig. 3) is dragged upwards and the magnet in it, getting closer to the sensor

8, closes the electric contact that switches the boiler d.h.w operation ON.

Fig. 2

1

7

C

B

A

1

2

3

14.2

Nomenclature and location of parts

(Fig. 3)

Flow switch plug

O---ring

Flow limiter

(optional for M96A.28SM/... M96A.32SM/...)

32

4

5

7

8

6

Fig. 3

14.3

Checks


n

Sensor operation


2 Disconnect the connectors B (Fig. 2) and measure the electrical resistance between the leads of the sensor. Without water being drawn, the contact must be open. By opening a hot water tap the contact must be close (electrical resistance zero Ω).

14.4

Removal of the

sensor

1

2




B and remove the sensor holder spring 7 (Fig. 2 --- Fig. 3).

Remove the sensor.

3

14.5

Removal of the flow switch group and d.h.w. circuit filter

1

2

3


Remove the front panel of the case and empty the d.h.w. circuit.

Remove the fork

C and pull up the flow switch plug 1 (Fig. 2 --- Fig. 3) with the help of a screwdriver.

To remove the filter from the flow switch group separate the filter 6 from the body 4 (Fig. 3) by levering it.

4 Reassemble the parts following the removing sequence in reverse order.

14.6

Flow limiter

The M96A.24SM/... model is factory fitted with a 10 litre/ min. flow limiter.

If on the M96A.28SM/... and M96A.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

Blue

Red

Pink

To install the flow limiter:

1

2

D.h.w. flow switch, filter and flow limiter

Remove the flow switch group as explained in the section 14.5.

Separate the flow switch plug 1 from the body 4

(Fig. 4) levering with a screwdriver one of the two hooks.

1

4

Fig. 4

3

4

Insert the flow limiter 3 as shown in Fig. 3

Reassemble the group following the above sequence in reverse order.

33

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. 1.

Ω

5500

5000

4500

4000

3500

3000

2500

2000

1500

1000

8500

8000

7500

7000

6500

6000

12500

12000

11500

11000

10500

10000

9500

9000

20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 ˚C

Fig. 1

On the boiler there are two Temperature probes. One on the output of the primary heat exchanger (c.h. Temperature probe) A in Fig. 2 and Fig. 3; one on the output of the d.h.w. heat exchanger (d.h.w. Temperature probe) B in Fig. 2 and Fig. 4.

A

15.2

Checks

n

Temperature---resistance relationship


Disconnect the cable from the Temperature probe.

Measure the temperature of the pipe

C where the Temperature probe is located and check the electrical resistance according to the graph in Fig. 1.

1

15.3

Removal of the c.h. Temperature probe


Remove all the case panels and the sealed chamber lid.

A

D

C

Fig. 3

2

3

Remove the electric connector

D and remove the c.h. Temperature probe A (Fig. 3)

Reassemble the c.h.Temperature probe carrying out the removal operations in reverse order.

15.4

Removal of the d.h.w.Temperature probe


Fig. 2

34

c.h.

return c.h.

flow d.h.w.

inlet

B d.h.w.

outlet

B

F E

Fig. 4

3

4

1

2


Empty the d.h.w circuit of the boiler.

Remove the fixing spring E (Fig. 4).

Remove the electric connector F and unscrew the d.h.w. Temperature probe B (Fig. 4).

5 Reassemble the d.h.w. Temperature probe carrying out the removal operations in reverse order.


Temperature probe

35

16

By---pass valve

16.1

Function

The By---pass valve A in Fig. 1 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

16.2

Removal


Remove all the case panels.


Remove the locking plate B and pull up the by--pass valve

A (Fig. 3).

Fig. 1

A

A

B

Fig. 2

4 Reassemble the by---pass valve as illustrated in

Fig. 2 reversing the order of removal.

36

17

Fan and Air pressure sensor

17.1

Function

The function of the Fan A (Fig. 1 and Fig. 2) 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 an Air pressure sensor

B (Fig. 1 and Fig. 2) .

C

A

A B

B

Fig. 2 n

Check of the Air pressure sensor operation

This test must be carried out with the sealed chamber closed

1

2

Remove the caps of the pressure test points located on the top of the boiler and connect a differential pressure gauge (Fig. 3).

Switch on the boiler.

Fig. 1

17.2

Checks

n

Check of the fan

1

2



Disconnect the connectors C (Fig. 2) and measure the electrical resistance of the motor that has to be about:

43 Ω --- M96A.24SM/...

25 Ω --- M96A.28SM/...

20 Ω --- M96A.32SM/...

(at ambient temperature).

Fig. 3

3

4

5

6

Run the boiler at minimum by disconnecting the gas valve modulation operator.

Compare the value on the gauge with the following:

75 Pa (0,75 mbar) --- M96A.24SM/...

92 Pa (0,92 mbar) --- M96A.28SM/...

105 Pa (1,05 mbar) --- M96A.32SM/...

Run the boiler at maximum (connect the modulation operator).

Compare the value on the gauge with the following:

125 Pa (1,25 mbar) --- M96A.24SM/...

155 Pa (1,55 mbar) --- M96A.28SM/...

165 Pa (1,65 mbar) --- M96A.32SM/...

37

C

A

Fan and Air pressure sensor

7 With values less than:

64 Pa (0,64 mbar) --- M96A.24SM/...

82 Pa (0,82 mbar) --- M96A.28SM/...

95 Pa (0,95 mbar) --- M96A.32SM/...

The ignition is not allowed and appropriate fault indication is given (see section 10.4)

17.3

Removal of the Fan

1

2

3

4




C and the earth connection D (Fig. 4).

Disconnect the pipe

E by the pressure test point

F (Fig. 4).

Unscrew the screw G and remove the bracket H

(Fig. 4).

F J I

E

D


17.4

Removal of the Air pressure sensor

3

4

1

2

5



Disconnect the wires I from the Air pressure sensor.

Remove the pipe

J from the Air pressure sensor.

Unscrew the screws which hold the Air pressure sensor to the frame.

Assemble the Air pressure sensor carrying out the removal operations in reverse sequence.

Warning: to correctly connect the Air pressure sensor, refer to Fig. 5

pressure point P2

J

H

G

Fig. 4

5

6

Remove the Fan by sliding it towards left (se the arrow in Fig. 4).

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.

Fig. 5


38

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.

Fig. 1 shows the electrodes configuration on the models M96A.24SM/..., M96A.28SM/....

Fig. 2 shows the electrodes configuration on the model

M96A.32SM/....

18.2

Checks

n

Check the position of the electrode edges

1

2


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. 3).

4 mm

Ignition

Ignition

Detection

Male

Female

Fig. 1

Detection

Male

Female

Fig. 2

Ignition

Fig. 3

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



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



Disconnect the electrode wires from the full sequence ignition device.

Remove the plate

E (see Fig. 3 on page 9).

Remove the burner by unscrewing the four screws placed at the right and left sides of the burner.

Unscrew the screws A (Fig. 4) which hold the electrodes to the burner.

Two screws are used on the models

M96A.24SM/..., M96A.28SM/...

Three screws, one for each electrode, are used on the model M96A.32SM/....

39

Ignition and detection electrodes

6

7

Extract the electrodes from the burner.

Assemble the electrodes carrying out the removal operation in reverse order.

Refer to Fig. 1 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.



Fig. 4

A

40

19

Safety thermostat

19.1

Function

The safety thermostat A in Fig. 1 and Fig. 2 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.

a temperature below that of the safety thermostat and no overheat intervention should occur.


n

Electrical function

1

2

Remove all the case panels and the lid of the sealed chamber.

Disconnect the wiring

B of the safety thermostat and check its electrical function. Normally (no intervention) the contact must be closed (electrical resistance zero Ω).

1

19.3

Removal


Remove all the case panels and the lid of the sealed chamber.

A

B A

C

Fig. 1

19.2

Checks

n

Overheat temperature value

1 Set the temperature control knobs to their max.

position and run the boiler in d.h.w. and c.h.

2 Allow the boiler to reach its maximum operating temperature (monitor the temperature gauge on the instrument panel). The boiler should maintain

Fig. 2

2

3

4

5

Disconnect the wiring

B (Fig. 2).

Remove the spring C which holds the overheat thermostat on the pipe of the primary heat exchanger and remove it.

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.


41

20


20.1

Function

The Flue temperature probe NTC A in Fig. 2 and Fig. 3 senses the temperature of the combustion products that flow through the condensing heat exchanger.

The relation between temperature and electrical resistance is stated in Fig. 1

Ω

18500

18000

17500

17000

16500

16000

15500

15000

14500

14000

13500

13000

12500

12000

11500

11000

10500

10000

9500

9000

8500

8000

7500

7000

6500

6000

5500

5000

4500

4000

3500

3000

2500

2000

1500

1000

10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 ˚C

Fig. 1

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.

A

Fig. 2

42

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.

A B

Fig. 3

20.2

Checks

n

Overheat temperature value

1 Set the temperature control knobs to their max.

position and run the boiler in d.h.w. and c.h.

2 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.

n

Temperature---resistance relationship.

1 Remove the probe (see section 20.3) to have it at room temperature.

2

3

The electric resistance of the Flue temperature probe NTC at room temperature of 20˚C must be of approximately 12000 Ω

For other temperatures of the probe check the electrical resistance according to the graph

(Fig. 1)

1

2

3

20.3

Removal



Disconnect the wires

B from the Flue temperature probe NTC (Fig. 3).

Unscrew and remove the thermostat probe

A

(Fig. 3) from the condensing heat exchanger.

4 Assemble the Flue temperature probe NTC carrying out the removal operations in reverse sequence.

Flue temperature probe NTC

43

21

Condensate trap

21.1

Function

The condensate trap A in Fig. 4 and Fig. 5 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.

When the condensate reaches the lower part of the exchanger obstructs the the exhaust gas flow and the boiler stops (no signal from the air pressure sensor).

21.2

Removal


5 Remove the front and right case panels.

6

7

Disconnect the trap from the draining pipe.

Using pliers, remove the spring B moving it upwards.

8

9

Disconnect the rubber pipe C.

Unscrew the nut

D and lower the trap.

10 Disconnect the wirings from the trap.

11 Reassemble carrying out the removal operations in reverse order.

C

A

B

D

A

Fig. 4

If the drain pipe is plugged or in any case in which the condensate isn’t correctly evacuated, the condensate level rises filling the trap and reaching the condensing heat exchanger.

Fig. 5

44

45

12

13 E01---204

E01---205

14 H58---670

15

16 169---010

17

18 E83---101

19

20

21

22

23 E83---127

H05---186

24 E83---126

H05---185

25 E83---122

H05---183

46

22

Short spare parts list

Key G.C. part no.

Description

1

2

3

4

5

173---148

173---149

169---069

169---070

E83---121

E94---576

H20---984

H50---420

6 H03---746

7

8

9

H50---189

E83---178

10 E83---180

E83---181

11

Burner (mod. M96A.24SM/...)



Injectors for natural gas (mod. M96A.24SM/...)



Injectors for LPG (mod. M96A.24SM/...)



Expansion vessel (mod. M96A.24SM/...,

M96A.28SM/...)

Expansion vessel (mod. M96A.32SM/...)

Main heat exchanger (mod. M96A.24SM/...)



Fan (mod. M96A.24SM/...)



Gas valve

Air pressure sensor

Safety valve

Combustion chamber side panels

Combustion chamber rear panel

(mod. M96A.24SM/...)

Combustion chamber rear panel

(mod. M96A.28SM/..., M96A.32SM/...)

Combustion chamber front panel

(mod. M96A.24SM/...)

Combustion chamber front panel

(mod. M96A.28SM/..., M96A.32SM/...)

Electronic regulation p.c.b.

D.h.w. heat exchanger (M96A.24SM/...)

D.h.w. heat exchanger (M96A.28SM/...,

M96A.32SM/...)

Pump


D.h.w. flow switch

Three way diverter valve (electric actuator)

Overheat thermostat


Fuse 3,15 AF

Temperature probe (d.h.w. circuit)

Temperature probe (main circuit)

Ignition electrode (left) (mod. M96A.24SM/...,

M96A.28SM/...)

Ignition electrode (left) (mod. M96A.32SM/...)

Ignition electrode (right) (mod. M96A.24SM/...,

M96A.28SM/...)

Ignition electrode (right) (mod. M96A.32SM/...)

Detection electrode (mod. M96A.24SM/...,

M96A.28SM/...)

Detection electrode (mod. M96A.32SM/...)

1

1

1

1

1

1

1

1

1

1

1

2

1

1

1

1

1

1

1

1

1

1

1

1

2

1

1

1

1

1

1

1

1

1

1

Q.ty Manufacturer part no.

Manufacturer’s reference

KI1004 102

Polidoro

KI1004 147

1 BI1213 106

12 KI1064 505 Polidoro

14

15 BI1213 109

12 KI1064 506

14

15 BI1213 110

1 BI1172 103 CIMM 6 litres

BI1182 105

BI1262 101

BI1262 130

BI1442 113

CIMM 7 litres

BI1536 105 Fime

BI1536 106 Fime

BI1536 113 Fime

BI1093 105 Sit 845

BI1536 103 HUBA 0---3mbar

BI1181 100 Watts

BI1326 100

BI1326 107

BI1326 108

BI1536 110

BI1536 111

BI2015 100 Bertelli & Partners

BI1001 101

BI1001 102

BI1911 103 Wilo NFSL 12/6 HEP---1

BI1351 118

KI1042 107

BI1351 108

BI1172 105 ELTH --- type 261

BI1536 104

BI1295 108

KI1042 501

BI1442 106

BI1123 101

BI1193 102

BI1123 103

BI1193 103

BI1123 102

BI1193 104

26 E83---145

27

Temperature---pressure gauge

Recuperator

1

2

1

1

BI1475 108 IMIT

BI1442 107

Short spare parts list

3

4

10

9

13

5

6

7 8

9

12

14

11

15 16 22

17

18 19 20 21 23 24 25 26

27

47

*1796215491*

17962.1549.1

5008 52A4 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

Biasi Riva Compact HE MK2 M96A.24SM/C, M96A.28SM/C, M96A.32SM/C gas boiler Service manual

Assistant Bot

Wall hung, fan flue, room sealed, high efficiency gas boiler

Service manual

RIVA COMPACT HE MK2

Models:

G.C. Appl. No.

Table of contents

Overall information

Overall View

Hydraulic diagram

Central heating (c.h.) operation

Domestic hot water (d.h.w.) operation

General access and emptying hydraulic circuits

Nomenclature

Body panels

Control panel

Emptying the primary circuit

Access to the sealed chamber

Emptying the d.h.w. circuit

Diagrams

Wiring diagram

Functional flow diagrams

Circuit voltages

Primary heat exchanger

Function

Removal

Cleaning

Condensing heat exchanger

Function

Removal

Cleaning

D.h.w. heat exchanger

Function

Removal

Pump

Function

Removal

Checks

Three way diverter valve

Function

Checks

Removal of the electric actuator

Removal of the diverter group

Removal of the tree way diverter valve

Electronic control/ignition p.c.b.

Function

Selection and adjustment devices

Checking the temperature

Operation lights

Setting the boiler control function modes

Useful output setting

Reignition frequency setting

Ignition gas pressure adjustment

Setting the tree way diverter valve operation mode

Checks

Removal of the electronic control p.c.b

Thermal control in the ” ” mode

Thermal control in the ” ” mode

Ignition and control sequence

Modulating gas valve

Function

Nomenclature of the parts (Fig. 2)

Adjustment

Checks

Removal of the

Removal of the gas valve

Primary circuit pressure switch

Function

Removal

Checks

Expansion vessel and temperature---pressure gauge

Function

Checks

Removal of the expansion vessel

Removal of the temperature---pressure gauge

D.h.w. flow switch, filter and flow limiter

Function

Nomenclature and location of parts

(Fig. 3)