Beretta Ciao C.A.I User manual

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CiaoC.A.I. - C.S.I.
Service Manual
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1 GENERAL
1.1 GENERAL INSTRUCTIONS
Make sure the supplied goods are intact and comple-
te after unpacking them and contact the boiler sales
point if there are any problems of nonconformity.
The boiler must be installed by BERETTA Servicing
Centre.
The boiler must be used for the purpose for which the
factory expressly designed it. The factory shall not be
held liable either contractually or non-contractually
for damages caused to persons, animals or objects,
caused by erroneous installation, regulation,
maintenance and improper use.
Should any water leak out, turn off the water supply
and contact BERETTA Servicing Centre.
Regularly check that the water system working
pressure is between 1 and 1.5 bar, if not, contact
BERETTA Servicing Centre.
The following operations should at least be done if the
boiler is not going to be used for a long time:
- Turn the main switch of the appliance and the general
switch of the system to “off”
- Turn off the fuel and water taps of the heating system
- Empty out the heating and sanitary systems if there is
any risk of freezing.
The boiler should be overhauled at least once a year.
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1.2 BASIC RULES FOR SAFETY
We would remind you that some basic rules for safety must
be followed with products using combustible substances,
electricity and water such.
Childrenandunassisteddisabledpersonsareforbidden
to use the boiler.
It is forbidden to work with devices or electrical
appliances such as switches, domestic appliances etc.
if there is a smell of fuel or unburned fuel.
In this is the case:
- Air the room by opening doors and windows
- Switch off the fuel on/off switch
It is forbidden to touch the boiler with bare feet or if
some parts of the body are wet.
No cleaning operations must be done before
disconnecting the boiler from the main electricity
supply, turning the main system switch to “off”.
It is forbidden to modify the safety or control devices
without permission and instructions from the boiler
manufacturers.
It is forbidden to tug, pull out and twist wiring coming
out of the boiler even if the latter is disconnected from
the main electricity supply.
It is forbidden to seal up or reduce the size of vents in
the installation premises, if existing. Vents are
indispensable for correct combustion and for safety.
It is forbidden to leave inflammable containers and
substancesinthepremises wheretheboiler is installed.
It is forbidden to expose the boiler to atmospheric
agents. It has not been designed for the open air and
does not have adequate anti-freeze systems.
It is forbidden to discard or leave packing material
within the reach of children, as it could be a potential
source of danger.
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1.3 GENERAL GUARANTEECONDICTIONS
The guarantee covers all the parts making up the products. It
covers repairs and eventually replacing any of the parts that the
supplier considers as having production defects, free of charge.
A qualified authorized person should ignite the boiler the first
time and then make out a certificate, signed for acceptance by
the customer.
The guarantee shall terminate if:
- the cause of defect has nothing to do with the product itself;
- non-original components, spare parts or wear materials have
been used;
- repair and servicing work has been done by non-authorized
persons;
- environmental or installation conditions differ from those
specified in section 7 page 71.
The guarantee does not cover quick wearing materials: filters,
gaskets, dials, etc.
1.4 IDENTIFICATION OF BOILER MODEL
Boilers can be identified through the Serial number plate:
Showing technical data and working characteristics.
Badhandling,removal,missingserialnumberplates
orany other preventingreliable identification ofthe
product,complicatesanyinstallationormaintenance
operation.
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Fig. 1.1

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1.5 IDENTIFICATION OF MAIN
COMPONENTS
(APPENDIX - A page 77)
INDEX
• Burner page 3
• Combustion chamber page 3
• Circulator page 3
• Igniter/control electrode page 4
• Flowmeter page 4
• Flow limiter page 4
• Water pressure switch page 4
• Safety pressure switch (C.S.I. only) page 4
• Filling tap page 5
• Bithermal exchanger page 5
• Air box (C.S.I. only) page 5
• Electronic control panel page 5
• NTC temperature control probes page 6
• Fumes thermostat (C.A.I. only) page 6
• Limit thermostat page 6
• By-pass valve page 6
• Gas valve page 6
• Safety valve page 7
• Expansion tank page 7
• Fan (C.S.I. only) page 7
• Venturi and Pitot tube page 7
1.5.1 Burner
(POS. 1 APPENDIX - A page 77)
The burner is installed underneath the combustion chamber
(Sect. 1.5.2 page 3) and serves to create the correct mixture of
air and gas for the combustion process.
Itconsists ofa series ofperforated rampsin stainlesssteel, linked
together and adequately spaced one from the other.
The gas flowing from the valve (Sect. 1.5.17 page 6) enters the
burner Venturi and mixes with primary air; the mixture then
comes out of the numerous openings made on the upper parts
of the ramps and ignites, thanks to the secondary air sucked
into the combustion chamber.
1.5.2 Combustion chamber
(POS. 2 APPENDIX - A page 77)
The combustion chamber is located at the centre of the boiler
and combustion occurs inside it.
It consists of a steel plate structure adequately folded to be
able to insert slabs of insulating material made of ceramic
fibre with normal working temperature of about 1200°C
and a melting point of about 1700°C.
1.5.3 Circulator
(POS. 3 APPENDIX - A page 77)
The circulator is installed on the return side of the boiler
water circuit and it facilitates the water circulation while
heating is on when the room thermostat signals a drop in heat.
The circulator is made of composite material with incorporated
degasser.
The current must be higher than that of the main power supply
at ignition to push the water into the central heating system;
this is why it is necessary for the condenser discharge to be
housed inside the connector box.
Water in the pump is circulated and pushed towards the
bi-thermal exchanger (Sect. 1.5.10 page 5) by the blades.
At the same time a vacuum is created inside the pump,
sucking other water from the system and triggering off the
circulation of primary fluid.
Fig. 1.2
Fig. 1.3
Fig. 1.4
Automatic air
vent bottle
Connection cover

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Ball cock
Filter
Segments
1.5.4 Igniter/control electrode
(POS. 4 APPENDIX - A page 77)
The electrodeis located near the centre rampof theburner(Sect.
1.5.1 page 3) and its job is to strike up the spark for ignition and
to control the presence of the flame.
The igniter plug consists of a metallic core and is coated on the
outside with ceramic material for electric insulation. The end
of the metal part is free from ceramic insulation and is located
at about 3 mm from the burner.
1.5.5 Flowmeter
(POS. 5 APPENDIX - A page 77)
The flowmeter is connected to the inlet on the sanitary side
of the boiler; the device is designed to control the water flow
with a ball cock consisting of a teflon spear valve, with a
magnetized sector on the upper part.
The ball cock is in stand-by position at the initial phase and the
internalcontactis open.Itrisesas thewaterflowsthrough making
thetwosegmentscometogether,theflowmetercontact thencloses
releasing electricity to the water in the boiler.
There is a filter at the cold water inlet to save the flowmeter
from passing impurities.
1.5.6 Flow limiter
The flow limiter is located at the inlet of sanitary water on the
bi-thermal exchanger (Sect. 1.5.10 page 5) and has the work
of reducing the sanitary water level to a maximum value of
101/min.
1.5.7 Water pressure switch
(POS. 6 APPENDIX - A page 77)
The water pressure switch is located on the right hand side of
the water heating unit; it is a device for controlling whether
there is a pressure or not in the primary system. Operating levels
are:
- ON system pressure > 0.45 bar;
- OFF system pressure < 0.45 bar.
1.5.8 Safety pressure switch (C.S.I only.)
(POS. 7 APPENDIX - A page 77)
The safety pressure switch is located on the upper part of
the air box (Sect. 1.5.11 page 5) and controls that the fan
(Sect. 1.5.20 page 7) and flues are working properly.
It consists of a double shell containing a silicone rubber
membrane. The membrane works a microswitch when the
difference in pressure indicated by the Venturi and the Pitot
tube (Sect. 1.5.21 page 7) falls to below the safety limit,
blocking the gas supply.
Fig. 1.5
Fig. 1.6
Fig. 1.7
Fig. 1.8
Fig. 1.9

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Compensating
outlet
Analysis
of outlets
Primary
water
flowing
Secondary
water
flowing
Turbo propeller
1.5.9 Filling tap
(POS. 8 APPENDIX - A page 77)
The filling tap is located at the sanitary inlet in the boiler and
hasthe job of connecting up the sanitarysystem withthe heating
system for filling or topping up (Sect. 7.4 page 72) .
1.5.10 Bi-thermal exchanger
(POS. 9 APPENDIX - A page 77)
The bi-thermal exchanger is located on the upper part of the
combustion chamber (Sect. 1.5.2 page 3) and is the part used
by the primary water (heating) and secondary (sanitary) water
for heating up by effect of heat generated in combustion.
It consists of a coil with two oval shaped tubes, one inside
the other, all fitted inside a commutator core which is
designed to increase the area of heat exchange. The entire
exchanger is coated with aluminium alloy to protect it from
corrosion.
The outside part of the coil is reserved for the flow of primary
fluid, flowing against the current of the secondary fluid.
The inside part is reserved for the flow of secondary water;
the coil has septum inside - turbo propeller - to increase
performance and to avoid temperature stratification.
1.5.11 Air box ( C.S.I. only)
(POS. 10 APPENDIX - A page 77)
The air box is at the centre of the boiler and serves to isolate all
components involved in the combustion process (burner,
combustion chamber, electrode, safety pressure switch,
exchanger and fan) from the domestic environment.
It is made up of four units in aluminised metal sheets with
neoprene sealing.
There is a compensation outlet connected to the gas valve
pressure regulator, at the bottom of the box. The outlet stabilizes
the membrane inside the regulator through a small tube.
The air box is designed to be able to analyse combustion
parameters without having to remove the case.
Measurements are taken through two pockets located on
the upper part, which are used to house probes for measuring
air temperature andpolluting fumes are inserted, after
removing the screw caps.
1.5.12 Electronic control panel
(POS. 11 APPENDIX - A page 77)
The electronic control panel is housed inside the control panel
and is designed to control the entire appliance.
It contains terminals for connecting up the boiler electrically
and for connecting a eventualy room thermostat (Sect. 7.3
page 71).
Fig. 1.10
Fig. 1.11 Fig. 1.13
Fig. 1.12

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1.5.13 NTC temperature control probes
(POS. 12 APPENDIX - A page 77)
NTC probes, Negative Temperature Control, are located at the
exchanger outlet (Sect. 1.5.10 page 5) on the heating side and
on the outlet ramp of the exchanger on the sanitary side
respectively; they measure the temperature of primary and
secondary water for the electronic control panel.
These are thermistors where the value of the heating element
drops as the temperature rises.
The instantaneous comparison between effective temperature of
the water and the one set by the User causes a change in the
current sent to the gas valve modulator coil (Sect. 1.5.10 page 5).
1.5.14 Fumes thermostat (C.A.I. only)
(POS. 13 APPENDIX - A page 77)
The fumes thermostat is located on the upper right hand side of
the hood; it is a device for controlling correct evacuation of
combustion products.
Combustion products will be discharged through slits on the
side of the hood if the flue should be obstructed, heating up the
thermostat so that it starts working.
1.5.15 Limit thermostat
(POS. 14 APPENDIX - A page 77)
The limit thermostat is on the heating side of the exchanger
(Sect. 1.5.10 page 5) and serves to prevent the boiler from
boiling.
It is an automatically set contact device, which will interrupt
the flame detection electrical circuit, should it work at a
temperature of about 110°C.
1.5.16 By-pass valve
The automatic by-pass is installed inside the duct
connecting the system’s delivery to CH return. Its job is to
guarantee primary water re-circulation in the boiler in
systems with high load loss.
The spring inside the by-pass valve is gauged to 530 gr. This
should be replaced with another one with increased capacity
if a high-headed circulator is used.
1.5.17 Gas valve
(POS. 15 APPENDIX - A page 77)
The gas valve is located under the combustion chamber (Sect.
1.5.2 page 3) and is the part designed to supervise burner
ignition, regulation and control operations.
The valve is made up of an aluminium pressofusion with two
solenoid valves, mechanically in series but parallel electrically.
The modulator is an integral part of the gas valve; the operator
modulates by changing the current to the coil to let the right
quantity of gas to flow to the burner. These configuration ensure
Fig. 1.14
Fig. 1.15
Fig. 1.16
Fig. 1.17
Heating
sensor
Sanitary
sensor
0 20 40 60 80 100
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
22000
24000
26000
28000
30000
32000
34000
0
RESISTANCE (ohm)
NOMINAL RESISTANCE
MINIMUM RESISTANCE
MAXIMUM RESISTANCE
TEMPERATURE (°C)

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Solenoid valves
Modulator
that gas flowing to the burner is stopped very quickly under
any faulty condition.
The modulator is an integral part of the gas valve; the operator
modulates by changing the current to the coil to let the right
quantity of gas to flow to the burner (Sect. 1.5.1 page 3).
1.5.18 Safety valve
(POS. 16 APPENDIX - A page 77)
The safety valve is located underneath the circulator (Sect. 1.5.3
page 3) and has the job of protecting water circulation from
eventual over pressure caused, for example, by an increase in
the volume of primary fluid due to heating effect. The valve is
gauged to an operating pressure of 3 bar.
1.5.19 Expansion tank (POS. 17 APPENDIX - A page 77)
The expansion tank is located between the two uprights of the
framework and has the job of compensating the increased
volume of primary fluid from heating effect, thanks to the work
done by a rubber membrane loaded with nitrogen beforehand
at 1 bar.
It has been scaled to meet with all engineering solutions
normally used in domestic central heating units. The current
production expansion tank has a capacity of 8 l. and is adequate
for a system containing about 100 l. It may eventually be
integrated with an auxiliary if it should prove to be insufficient.
1.5.20 Fan (C.S.I. only)
(POS. 18 APPENDIX - A page 77)
The fan is located above the combustion chamber (Sect. 1.5.2
page 3) and serves to expel combustion products from the air
box (Sect. 1.5.11 page 5).
Specifically designed for this kind of application, it has the
characteristic of being absolutely silent with top performance.
1.5.21 Venturi and Pitot tube (C.S.I. only)
(POS. 19 APPENDIX - A page 77)
TheVenturi andPitottube areinstalledon the fanscrewconveyor
(Sect. 1.5.20 page 7) and continuouslycorrect scavenging of
products of combustion.
The first device has the job of signalling static pressure value
as combusted gas flows through, while the second measures
thetotal pressure.The differenceinpressure workson thesafety
pressure switch membrane (Sect. 1.5.8 page 4), through two
small tubes, switching on the microswitch.
Fig. 1.19
Fig. 1.20
Fig. 1.21
Fig. 1.22
Fig. 1.18

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DHW
OUT IN
1.6 DESCRIPTION OF OPERATING
PRINCIPLES
1.6.1 Hydraulic operating principle in DHW
(Fig. 1.23)
When service water taking cock (1) is opened, system water
flows back to DHW input (2), through capacity regulator (3)
and the flow-meter (4). Water getting through the flow-meter,
exceeding a 2,5 l/min capacity, pushes float, located inside it,
upward. This movement allows closing the electric contact,
located in a device out of the flow-meter. By a connection ramp
(5), water flows from flow-meter to flow limiting device (6)
and then into bi-thermal exchanger (7).
1.6.2 Electric operating principle in DHW
(see APPENDIX - E pages 81, 82)
In order to get hot water ready only, in summer, set function
selector on « » DHW symbol. When hot water cock is
opened and capacity exceeds 2,5 l/min, the flow-meter,
measuring water flowing through the circuit, check pressure
switch closing by electric enabling; the pressure switch starts
ignition sequence:
- C.A.I. version:
When activated, water pressure switch enables ignition; gas
valve operating devices are fed.
- C.S.I. version:
When activated, water pressure switch feeds the fan, while
gas valve operating devices are fed.
Under temperature request condition, the burner switches on
and gas solenoid valve proportionally opens shutter to allow
slow burner ignition- automaticallyadjusted bymicroprocessor
- then maximum power is reached until temperature set on
selector is obtained.
According to taking capacity, burner flame automatically fits
hot water requests.
Both temperature selector and sensor provide for a resistance
value to board integrated component, which, at the beginning
(cold) controls burner maximum operation, until temperature
read on secondary by NTC sensor, compared by main board
integrated component, with resistance set on DHW temperature
selector, approaches temperature set: then minimum level is
reached in modulation phase.
The burner switches off 5°C after temperature set and switches
on 1°C below.
Finally, when DHW cock is opened, the operating sequence is
the following:
C.A.I. version
Flow-meter
Water pressure switch check
Burner
C.S.I. version
Flow-meter
Water pressure switch check
Quiescent safety pressure switch
Fan
Safety pressure switch enabled
Burner
1.6.3 DHW temperature adjustment
To adjust DHW temperature (bathrooms, shower, kitchen, etc.)
to adjust CH temperature, remove function selector and act on
right potentiometer (Fig. 1.24).
Fig. 1.23
Fig. 1.24