Biasi M90E.24S User manual

Wall hung, fan flue, room sealed gas boiler
SERVICE MANUAL
RIVA COMPACT
Models: G.C. Appl. No.
M90E.24S 47--970--17
M90E.28S 47--970--18
M90E.32S 47--970--21
Leave this manual adjacent to the gas meter
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

1
Ta b l e o f c o n t e n t s
1 Overall information 2..................
1.1 Overall View 2.........................
1.2 Hydraulic diagram 2....................
2 General access and emptying
hydraulic circuits 3....................
2.1 Nomenclature 3........................
2.2 Body panels 3.........................
2.3 Control panel 3........................
2.4 Access to the sealed chamber 4.........
2.5 Emptying the primary circuit 4...........
2.6 Emptying the d.h.w. circuit 4............
3Diagrams 5...........................
3.1 Wiring diagram 5.......................
3.2 Circuit voltages 6......................
4Faultfinding 7........................
5 Primary heat exchanger 9..............
5.1 Characteristics 9.......................
5.2 Removal 9............................
5.3 Cleaning 9............................
6 D.h.w. heat exchanger 10...............
6.1 Function 10.............................
6.2 Removal 10............................
7Pump 11...............................
7.1 Function 11.............................
7.2 Checks 11.............................
7.3 Removal 11............................
8 Three way diverter valve 12.............
8.1 Function 12.............................
8.2 Checks 12.............................
8.3 Removal of the electric actuator 12........
8.4 Removal of the diverter group
and its internal parts 13..................
9 Electronic starting control p.c.b. 14......
9.1 Function 14.............................
9.2 Selection and adjustment devices 14......
9.3 Checking the temperature 15.............
9.4 Operation lamps 15.....................
9.5 Setting the boiler control function modes 16
9.6 Reignition frequency setting 16...........
9.7 Ignition gas pressure adjustment 16.......
9.8 Adjustment of useful c.h. output 17........
9.9 Gas conversion 18......................
9.10 Checks 19.............................
9.11 Removal of the electronic control p.c.b 19..
9.12 Thermal control in the ” ”mode 21......
9.13 Thermal control in the ” ”mode 22......
10 Modulating gas valve 23................
10.1 Function 23.............................
10.2 Nomenclature of the parts 23.............
10.3 Adjustment 23..........................
10.4 Checks 24.............................
10.5 Removal of the on---off operators coils 24..
10.6 Removal of the gas valve 24..............
11 Primary circuit flow switch 25...........
11.1 Function 25.............................
11.2 Checks 25.............................
11.3 Removal 25............................
12 Expansion vessel and
temperature -- pressure gauge 26........
12.1 Function 26.............................
12.2 Checks 26.............................
12.3 Removal of the expansion vessel 26.......
12.4 Removal of the temperature---pressure
gauge 26...............................
13 D.h.w. flow switch, filter and flow limiter 27
13.1 Function 27.............................
13.2 Nomenclature and location of parts 27.....
13.3 Checks 27.............................
13.4 Removal of the flow switch sensor 27......
13.5 Removal of the flow switch group
and d.h.w. circuit filter 28.................
13.6 Flow limiter 28..........................
14 Temperature probe 29..................
14.1 Function 29.............................
14.2 Checks 29.............................
14.3 Removal 29............................
15 By--pass valve 30......................
15.1 Function 30.............................
15.2 Removal 30............................
16 Fan, venturi device and Air pressure
switch 31..............................
16.1 Function 31.............................
16.2 Checks 31.............................
16.3 Removal of the Fan 31...................
16.4 Inspection and removal of the venturi
device 32..............................
16.5 Removal of the Air pressure switch 32.....
17 Ignition and detection electrodes 33.....
17.1 Function 33.............................
17.2 Checks 33.............................
17.3 Removal 33............................
18 Safety thermostat 35...................
18.1 Function 35.............................
18.2 Checks 35.............................
18.3 Removal 35............................
19 Short spare parts list 37................

2
1Overall information
1.1 Overall View
Fan
Safety
thermostat
Main heat
exchanger
Burner
Ignition
electrodes
Gas valve
Control
panel
Combustion
chamber
Automatic
air release
Pump
D.h.w. temp.
probe
D.h.w.
heat exchanger
Expansion
vessel
Detection
electrode
valve
D.h.w
flow switch
Diverter valve
Air pressure
switch
Main circuit
flow switch
1.2 Hydraulic diagram
Central heating (c.h.) operation Domestic hot water (d.h.w.) operation
C.h.
water flow
C.h.
water return
D.h.w.
inlet
D.h.w
outle
t

3
2General access and emptying
hydraulic circuits
2.1 Nomenclature
2
6
1
54
3
Fig. 1
1 Right side panel
2 Front panel
3 Control panel lid
4 Control panel cover
5Servicepanel
6 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 oper-
ations it is necessary to remove one or more panels of
the case.
Thesidepanelscanberemovedonlyaftertheremoval
of the front panel.
To remove the front panel remove screws A(Fig. 2), lift
the panel and remove it.
A
Fig. 2
To remove the side panels loosen the screws Band C
(Fig. 3), bring the base of the panels away from the
boiler and lift them, freeing them from the top hooks.
B
D
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.
To gain access to the parts located inside the control
panel proceed as follows:
1 Remove the front panel of the case
2 Loosen the screws Band C(Fig. 3).
3RemovethescrewsD
4 Move the lower part of the side panels as indi-
cated in Fig. 4 and pull the control panel.
When completely pulled out, the panel can rotate
45˚downwards to facilitate the service oper-
ations on the internal parts.

General access and emptying hydraulic circuits
4
Fig. 4
5RemovethescrewsEand remove the service
panel (Fig. 5);
6 To gain access to the electronic regulation PCB
and the full sequence ignition device remove the
screws Fand remove the control panel lid
(Fig. 5);
E
F
F
Fig. 5
2.4 Access to the sealed chamber
G
G
Fig. 6
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 Gas indicated in Fig. 6
and remove the lid.
2.5 Emptying the primary circuit
1 Close the c.h. circuit flow and return cocks H.
(Fig. 7).
H
H
J
Fig. 7 --- bottom view of the boiler
2 Remove the front and right panels of the boiler.
3 Open the drain tap I(Fig. 8) until the boiler is com-
pletely emptied.
4 Close drain tap again once the emptying has
been completed.
I
Fig. 8
2.6 Emptying the d.h.w. circuit
5 Close the d.c.w. inlet cock J(Fig. 7);
6 Open one or more hot water taps until the boiler
has been completely emptied.

5
3Diagrams
3.1 Wiring diagram
ON
1
L N
g/v
g/v cm
Electrical
supply terminal
block
c
m
gr
n
M
~
tt
probe NTC
DHW temperature
probe NTC
CH temperature
COM
NO mg/v c
n
n
c
ccbr
r
DHW flow
switch pressure switch
Primary
diverter valve
Three way
Pump
Modulating gas valve
n
b
n
g/v
m
b
g/v
r
n
c
nn
c
c
gr n
cb
rr
M
~NO
COM
n
gr
b
gr
g/v nc
g/v
g/v
g/v
Fan Safety
thermostat
Air pressure
switch
ignition
electrodes
Flame detection
electrode
gr
n
c
g/v
m --- b r o w n
c --- b l u e
n --- b l a c k
b --- w h i t e
r --- r e d
gr--- grey
a --- o r a n g e
g --- y e l l o w
g/v --- yellow/green
r
1
2
3
M
~
rcn
3
2
1
r
c
Wiring diagram for boiler equiped with full sequence ignition device type: ceza
Time switch
r
n
b
v
gr
v --- g r e e n
123
mc n
m
n
c
External controls
terminal block
bn

Diagrams
6
3.2 Circuit voltages
ON
1
230~
Fan
0
Safety
thermostat
230~
Eletric supply
terminal block
230~
0230~
0
3waydiverter
valve
230~
Pump
230~
Gas valve
Modulating
Electrical voltages with burner on
during c.h. or d.h.w. operation
only during c.h. operation
only during d.h.w. operation

7
4Fault finding
Components to check
Section of the manual ! (note ref. in brackets)
---
(2)
---
(3)
---
(4)
---
(5)
67.2 8.2 9.10 10.4 11.2 13.5 14.2 15 16.2 17.2 18.2 ---
(8)
---
(9)
--- ---
Appliance operation
lamp green (1)
L o c k --- o u t s i g n a l l a m p r e d
Defect #
Power supply line
Gas supply line
Flue pipes
C.h. circuit
D.h.w. circuit
D.h.w. heat exchanger
Pump
Diverter valve
D.h.w. flow switch
Fuse (regulation p.c.b.)
regulation ignition p.c.b
Function selectors (reg. p.c.b)
Gas valve (on--- off operators)
Gas valve (modulating operator)
Main circuit flow switch
D.h.w. filter
Main circuit temp. probe
D.h.w. temp. probe
B y --- p a s s v a l v e
Fan and venturi device
Air pressure switch
Ignition electrode
Detection electrode
Safety thermostat
Injectors
Expansion vessel
Safety valve
Pressure gauge
OFF
OFF
The boiler does not start either in c/h or d.h.w. mode. Fan still.
J J J
By pressing the reset push--- button the boiler turns on and operates correctly.
J J
(7)
J J J
u
lses
By pressing the reset push--- button the boiler starts the ignition cycle. The burner doesn’t light on, the igni-
tion sparks continue and the boiler locks again.
J J J J
O N --- f a s t p u
ON
By pressing the reset push--- button the boiler starts the ignition cycle. The burner lights on, the ignition sparks continue and the boiler locks again.
J J J J J
The burner doesn’t light either in c.h. or d.h.w. mode. Fan turn.
J J J J
The burner doesn’t light either in c.h. or d.h.w. mode. Fan doesn’t turn.
J J J J J J J J
fast pulses
The boiler doesn’t control the d.h.w. temperature. Turning the d.h.w. temp. adjustment knob hasn’t effect on the modulation of the flame. The boiler operates correctly on c.h.
J J
O N ---
f
OFF
The boiler lights for a short while on c.h. Normal operation on d.h.w. function.
J J

8
Components to check
Section of the manual ! (note ref. in brackets)
---------
(9)
---
(8)
18.217.216.21514.213.511.210.49.108.27.26---
(5)
---
(4)
---
(3)
---
(2)
Appliance operation
lamp green (1)
Pressure gauge
Safety valve
Expansion vessel
Injectors
Safety thermostat
Detection electrode
Ignition electrode
Air pressure switch
Fan and venturi device
B y --- p a s s v a l v e
D.h.w. temp. probe
Main circuit temp. probe
D.h.w. filter
Main circuit flow switch
Gas valve (modulating operator)
Gas valve (on--- off operators)
Function selectors (reg. p.c.b)
regulation ignition p.c.b
Fuse (regulation p.c.b.)
D.h.w. flow switch
Diverter valve
Pump
D.h.w. heat exchanger
D.h.w. circuit
C.h. circuit
Flue pipes
Gas supply line
Power supply line
Defect #
L o c k --- o u t s i g n a l l a m p r e d
The boiler does not supply d.h.w. (cold water from the tap). Regular operation in c/h mode even during a drawing off d.h.w.
J J J
On c/h mode the temperature of the main circuit reaches 75°Candthec/h
system does not heat. The boiler operates correctly on d.h.w. mode.
J J
Incorrect modulation J J J
s
Noisy bolier J J
m
al pulse
s
The boiler operates correctly but the gas pressure to the burner remains at minimum.
J J
--- n o r
m
F
Poor d.h.w. temperature J J J J J
(10)
ON
-
OF
F
Low d.h.w. flow rate J J J
--- ---
Water leaks from the safety valve during operationonc/h
J J J J
--- ---
Water leaks from the safety valve when the boiler is off.
JJJ
Note 1 For details see section 9.4 of this manual.
Further useful information can be obtained by switching the electronic control p.c.b. in the service operation mode (see section 9.4 of this manual).
2 Check for 230V~ between line (L) and neutral (N)
Verify the integrity of supply cable, plug and external fuses. Check the polarity of line and neutral connection
3 Verify the soundness of the gas supply pipe, the position of
stop valves. Check the gas pressure at the inlet test point of the gas valve (see sect. 10.3) with the boiler at rest and during operation and compare it with the values given on the installation booklet.
4 Check for soundness and absence of obstructions. Verify that
the flue terminal is correctly installed (see clearances) and en- sure that exhaust gas is not sucked back by the boiler.
5 Check for soundness of the circuit and verify its correct filling
(see also installation manual).
6 A j a m m e d b y --- p a s s c o u l d c a u s e t h e o v e r --- h e a t i n g o f t h e m a i n
circuit and the intervention of the safety thermostat.
7Checktheminimum gas pressure at the outlet test point of the
gas valve (see sect. 10.3) and compare it with the value given on the installation booklet.
8 Verify the cleanness of injectors. 9 Check the pressurization of the expansion vessel. Refer to the
installation manual for proper values.
10 d.h.w. pressure too high or flow rate too high. If necessary in-
sert a flow rate limiter (13.6).