Biasi Riva Plus HE M296.24SR/C User manual

Wall hung, fanflue, roomsealed, high efficiency gas boiler
Service manual
Riva Plus HE
Models G.C. Appl. No.
M296.24SR/C 41-583-18 SYSTEM BOILER
M296.28SR/C 41-583-19 SYSTEM BOILER
Leave this manual adjacent to the gas meter
Warning:
Service / repairs must be carried out, only by a qualified Gas Safety
Registered Engineer, who will be responsible for the current Regulations for
gas appliances.
Note:
After servicing, complete the relevant Service Interval Record section of the
Benchmark Checklist of the user and installation manual.

- 3 -
Table of conTenTs
1 OVERALL INFORMATION .................... 4
1.1 Overall View ................................4
1.2 Hydraulic diagram ............................4
2 GENERAL ACCESS AND EMPTYING HYDRAULIC
CIRCUITS ................................. 5
2.1 Nomenclature ...............................5
2.2 Body panels ................................5
2.3 Control panel................................5
2.4 Access to the sealed chamber ..................6
2.5 Emptying the primary circuit ....................6
3 DIAGRAMS................................ 7
3.1 Wiring diagram ..............................7
3.2 Circuit voltages ..............................8
4 FAULT FINDING ............................ 9
5 PRIMARY HEAT EXCHANGER . . . . . . . . . . . . . . . .11
5.1 Function ..................................11
5.2 Removal ..................................11
5.3 Cleaning ..................................11
6 CONDENSING HEAT EXCHANGER . . . . . . . . . . . 12
6.1 Function ..................................12
6.2 Removal ..................................12
6.3 Cleaning ..................................12
7 PUMP ................................... 14
7.1 Function ..................................14
7.2 Checks ...................................14
7.3 Removal pump .............................14
7.4 Removal electrical capacitor ...................15
8 ELECTRONIC CONTROL/IGNITION P.C.B. ..... 16
8.1 Function ..................................16
8.2 Selection and adjustment devices...............16
8.3 Checking the temperature.....................17
8.4 Operation lights .............................17
8.5 Setting the boiler control function modes .........18
8.6 Useful output setting .........................18
8.7 C.H. only mode setting .......................19
8.8 Reignition frequency setting ...................20
8.9 Ignition gas pressure adjustment ...............20
8.10 Checks ...................................21
8.11 Removal of the electronic control p.c.b ...........21
8.12 Thermal control in the mode ................22
8.13 Ignition and control sequence ..................23
9 MODULATING GAS VALVE .................. 24
9.1 Function ..................................24
9.2 Nomenclature of the parts.....................24
9.3 Adjustment ................................24
9.4 Checks ...................................25
9.5 Removal of the on-off operators coils ............25
9.6 Removal of the gas valve .....................25
10 PRIMARY CIRCUIT FLOW SWITCH ........... 26
10.1 Function ..................................26
10.2 Checks ...................................26
10.3 Removal ..................................26
11 EXPANSION VESSEL AND TEMPERATURE-PRES-
SURE GAUGE ............................ 27
11.1 Function ..................................27
11.2 Checks ...................................27
11.3 Removal of the expansion vessel ...............27
11.4 Removal of the temperature-pressure gauge ......27
12 TEMPERATURE PROBE . . . . . . . . . . . . . . . . . . . . 28
12.1 Function ..................................28
12.2 Checks ...................................28
12.3 Removal of the c.h. Temperature probe ..........28
13 BY-PASS VALVE .......................... 29
13.1 Function ..................................29
13.2 Removal ..................................29
14 FAN AND AIR PRESSURE SENSOR........... 30
14.1 Function ..................................30
14.2 Checks ...................................30
14.3 Removal of the Fan..........................31
14.4 Removal of the Air pressure sensor .............31
15 IGNITION AND DETECTION ELECTRODES .... 32
15.1 Function ..................................32
15.2 Checks ...................................32
15.3 Removal ..................................32
16 SAFETY THERMOSTAT..................... 33
16.1 Function ..................................33
16.2 Checks ...................................33
16.3 Removal ..................................33
17 FLUE TEMPERATURE PROBE NTC........... 34
17.1 Function ..................................34
17.2 Checks ...................................34
17.3 Removal ..................................34
18 CONDENSATE TRAP....................... 35
18.1 Function ..................................35
18.2 Removal ..................................35
19 SHORT SPARE PARTS LIST ................. 36

- 4 -
OVERALL INFORMATION
1 OVERALL INFORMATION
1.1 Overall View
Figure 1.1
Fan
Safety
thermostat
Main heat
exchanger
Burner
Ignition
electrodes
Gas valve
Control
panel
Combustion
chamber
Automatic
air release
valve
Pump
Detection
electrode
Combustion
chamber over heat
Condensing
heat exchanger
Flue temperature
probe NTC
C.H.
temp. probe
Primary circuit
pressure switch
Condensate
trap
Air pressure
sensor
C.h. pressure
relief valve
By-pas
s
valv
e
Expansion
vesse
l
1.2 Hydraulic diagram
Figure 1.2
Central heating (c.h.) operation
C.h.
water flow
C.h.
water return

- 5 -
GENERAL ACCESS AND EMPTYING HYDRAULIC CIRCUITS
2 GENERAL ACCESS AND EMPTYING
HYDRAULIC CIRCUITS
2.1 Nomenclature
Figure 2.1
6
1
2
3
4
5
1 Right side panel
2 Front panel
3 Control panel lid
4 Control panel cover
5 Service panel
6 Left side panel
2.2 Body panels
Warning: isolate the boiler from the mains electrici-
ty supply before removing any covering or compo-
nent.
For the most part of the check and maintenance operations it is
necessary to remove one or more panels of the case.
The side panels can be removed only after the removal of the
front panel.
To remove the front panel remove screws A(Figure 2.2), lift the
panel and remove it.
Figure 2.2
A
To remove the side panels loosen the screws Band C(Figure
2.3), bring the base of the panels away from the boiler and lift
them, freeing them from the top hooks.
Figure 2.3
D
B
B
C
- Bottom view of the boiler
2.3 Control panel
Warning: isolate the boiler from the mains electrici-
ty supply before removing any covering or compo-
nent.
To gain access to the parts located inside the control panel pro-
ceed as follows:
1 Remove the front panel of the case
2 Loosen the screws B and C (Figure 2.3).
3 Remove the screws D
4 Move the lower part of the side panels as indicated in Figure
2.4 and pull the control panel.
When completely pulled out, the panel can rotate 45° down-
wards to facilitate the service operations on the internal parts.

- 6 -
GENERAL ACCESS AND EMPTYING HYDRAULIC CIRCUITS
Figure 2.4
5 Remove the screws Eand remove the service panel (Figure
2.5);
6 To gain access to the electronic regulation PCB remove the
screws F and remove the control panel lid (Figure 2.5);
Figure 2.5
E
F
F
2.4 Access to the sealed chamber
Figure 2.6
G
G
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 Figure 2.6 and remove the lid.
2.5 Emptying the primary circuit
1 Closethec.h.circuitowandreturncocksH (Figure 2.7).
Figure 2.7
H
2 Remove the front and right panels of the boiler.
3 Open the drain tap I(Figure 2.8) until the boiler is completely
emptied.
4 Close drain tap again once the emptying has been complet-
ed.
Figure 2.8
I

- 7 -
DIAGRAMS
3 DIAGRAMS
3.1 Wiring diagram
Figure 3.1
123
L N
gnye bubn
bn
bkbu
bn bubn bk bu
gnye
bn bu
bn
bu
M
~
bu bn gnye
t
wh
wh
tbu
bu
bk
bk
Ignition
electrodes Flamed
etection
electrode
Externalcontrols
terminal block
Electric supply
terminal block
Pump
M
~
Primarycircuit
flow switch
Airpressure
sensor
C.h. temperature
probeNTC
Modulating
gasvalve
Flue
probeNTC
ye
gy
bn =brown
bu =blue
bk =black
wh =white
rd =red
gy =grey
gn =green
ye =yellow
vt =violet
og =orange
gnye =green/yellow
bubn gnye
bu
bk
bu bu
bn
bu
bk wh wh
rd
rd
P
rd
ye
gy
rd
gy
ye
gy
gy
bk
bk
ye
gy
1
2
3
1
3
4
bu
*=alternative
gnye
bkbk
Safety
thermostat
bk
Combustion
chamber
over heat
bk bk
bkbk
Fan

- 8 -
DIAGRAMS
3.2 Circuit voltages
Figure 3.2
Electrical voltages with burner on during c.h. or d.h.w. operation
Supply network
230~
230~
Pump
230~
Modulating
Gasvalve
Safety
thermostat
0
Fan
230~
+12VDC
Air
sensor
pressure
0,5±4,5VDC

- 9 -
FAult Finding
Components to check
Section of the manual ! (note ref. in brackets)
---
(1)
---
(2)
---
(3)
18.1 ---
(4)
7.2 8.10 9.4 10.2 12.2 13 14.2 15.2 16.2 17.1 ---
(7)
---
(8)
--- ---
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
Condensate drain pipe and trap
C.h. circuit
Pump
Fuses (Electronic p.c.b.)
Electronic p.c.b.
Boiler settings
Gas valve (on---off operators)
Gas valve (modulating operator)
Main circuit flow switch
Main circuit temp. probe
By---pass valve
Fan
Air pressure sensor
Ignition electrode
Detection electrode
Safety thermostat
Flue probe NTC
Injectors
Expansion vessel
Safety valve
Pressure gauge
By pressing the reset push --- button the boiler turns on and operates cor- rectly.
J J
(6)
J J J
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 J
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 J
The boiler does not start either in c/h mode. All the operation lights OFF Fan still.
J J J
The burner doesn’t light either in c.h. mode. Fan turns.
J J J J J
The burner doesn’t light either in c.h. mode. Fan doesn’t turn.
J J J J J J J
OFF
The boiler lights for a short while on c.h..
J J
4 FAULT FINDING

- 10 -
FAult Finding
7
Components to check
Section of the manual ! (note ref. in brackets)
---------
(8)
---
(7)
17.116.215.214.21312.210.29.48.107.2---
(4)
18.1---
(3)
---
(2)
---
(1)
L o c k --- o u t s i g n a l l a m p r e d
Pressure gauge
Safety valve
Expansion vessel
Injectors
Flue probe NTC
Safety thermostat
Detection electrode
Ignition electrode
Air pressure sensor
Fan
By---pass valve
Main circuit temp. probe
Main circuit flow switch
Gas valve (modulating operator)
Gas valve (on--- off operators)
Boiler settings
Electronic p.c.b.
Fuses (Electronic p.c.b.)
Pump
C.h. circuit
Condensate drain pipe and trap
Flue pipes
Gas supply line
Power supply line
Defect #
On c/h mode the temperature of the main circuit reaches 75C and the c/h system does not heat.
J
Incorrect modulation J J J Noisy bolier J J
OFF
The boiler operates correctly but the gas pressure to the burner remains at minimum.
J J
---
Water leaks from the safety valve dur- ing operation on c/h
J J J J
---
Water leaks from the safety valve when the boiler is off.
J J J
Note Useful information can be obtained also from the optical indication given by the appliance oper- ation lights (see section 8.4). 1 Check for 230V~ between line (L) and neutral (N)
Verify the integrity of supply cable, plug and external fuses. Check the polarity of line and neutral connection
2 Verify the tightness 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. 9.3) with the boiler at rest and during operation and compare it with the values given on the installation booklet.
3 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.
4 Check for soundness of the circuit and verify its correct filling
(see also installation manual).
5 A jammed by---pass could cause the over---heating of themain
circuit and the intervention of the safety thermostat.
6 Check the minimum gas pressure at the outlet test point of the
gas valve (see sect. 9.3) and compare it with the value given on the installation booklet.
7 Verify the cleanness of injectors. 8 Check the pressurization of the expansion vessel. Refer to the
installation manual for proper values.