Manuale Mynute Csi_ing

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Mynute C.S.I.

T E C H N

I C A L M A

N U A L TECHNICAL MANUAL



T E C H N I C A L M A

N U A L



3

INTRODUCTION

Each product of Beretta range is the result of

careful studies aiming at meeting each user’sneeds. In brief, the main characteristics of

Mynute C.S.I. are the following:

• harmonious shape, allowing its installation

in all environments;

• limited dimensions making its installation

in narrow environments easier;

• cont inuous electronic modulat ion,

adjusting thermal capacity to burner in both

CH and DHW phases;

• new low-load-loss distribution hydraulic

unit;

• new DHW exchanger reducing waiting

times to half (only C.S.I.).

Certainly, the above-mentioned are

commercial optionals, but answers to each

performance, installation and maintenance

questions are available in the table of

contents.

Beretta




N U A L

Section 0 Reference TablesTab. A Measuring units PAGE 6

Tab. B Conversion of measuring units PAGE 7

Section 1 Technical data1.1 Model description PAGE 8

1.2 Safety devices PAGE 8

1.3 Technical characteristics PAGE 8

1.4 Table of technical data PAGE 9

1.5 Table of Law 10 PAGE 10

1.6 Overall dimensions PAGE 10

Section 2 Description of main components2.1 Primary heat exchanger PAGE 12

2.2 Combustion chamber PAGE 12

2.3 Main burner PAGE 12

2.4 Ignition and detection electrode PAGE 13

2.5 Air box PAGE 13

2.6 Circulator PAGE 13

2.7 Expansion tank PAGE 14

2.8 Hydraulic unit PAGE 14

2.9 Gas valves PAGE 17

2.10 Controlling appliances PAGE 18

2.11 Boiler feeder PAGE 18

2.12 Venturi and Pitot pipe PAGE 182.13 Limit thermostat PAGE 19

2.14 Fan PAGE 19

2.15 Safety pressure gauge PAGE 19

2.16 NTC control sensor PAGE 20

Section 3 Description of operating principles3.1 Hydraulic operating principle in DHW PAGE 20

3.2 Electric operating principle in DHW PAGE 21

3.3 Hydraulic operating principle in CH PAGE 22

3.4 Electric operating principle in CH PAGE 23

Section 4 Installation of appliance4.1 Equipment PAGE 25

4.2 Unpackage PAGE 25

4.3 Union plate installation PAGE 26

4.4 Connection of gas supply PAGE 26

4.5 CH delivery and return connection PAGE 27

4.6 DHW delivery and return connection PAGE 27

4.7 Safety valve exhaustion connection PAGE 27

4.8 System washing PAGE 27

4.9 CHsystem loading PAGE 27

4.10 Outdoor installation PAGE 27

TABLE OF CONTENTS




N U A L

Tab. AMeasuring units

DIMENSION UNIT DESCRIPTION

SECTION 0Reference tables

Heating power W Watt

kW kiloWatt

kcal/h kilocalories/hour

Electric power W Watt

Supply voltage V Volt alternate current

Vdc Volt direct current

Electric frequency Hz Hertz

Pressure bar bar

mbar millibar Atm Atmospheremm C.A. millimetres in colums

of water

Temperature °C degree centigrade (celsius)

Elettric current A Ampere

Time s secondmin minute

h hour

Volume l litre

Mass kg kilogram

Capacity l/min litre/minute

l/h litre/hour

Lenght mm millimetrem metre

Velocity m/s metres/second

m/min metres/minute

Angular velocity g/min revolutions/minute

Electric resistance ý ohm

k ý kilo ohm



7

Tab. BConversion of measuring units

m/s km/h m/min

1 3,6 60

0,277 1 16,62

0,0166 0,602 1

m/s

km/h

m/min

W kW kcal/h

1 10-3 0,863

103 1 8,63

1,16 1,16 • 10-3 1

W

kW

kcal/h

Pa (N/m2) Atm bar

1 9,9 • 10-6 10-5

1,01 • 105 1 1,013

10

5

9,9 • 10

-1

1

Pa (N/m2)

Atm

bar

mm C.A.

10,2

10,33 • 103

10,2 • 10

3

9,81 • 106 96,8mm C.A. 10,981 • 102

VELOCITY

POWER

PRESSURE




N U A L

1.1Model description

Research lead by Beretta has taken to Mynute

C.S.I., a boiler for heating and producingdomestic hot water. It is a C12-C22-C32 type

appliance, with tight combustion chamber equipped with intakes for combustionanalyses and double exhaustion. The

hydraulic circuit uses a new compact unit,conceived and designed for hydraulic andelectric interlocking of DHW and CH

operation.Burner is adjusted by continuous electronic

modulation.

1.2Safety devices

• Tight combustion chamber.

• Double-shutter gas valve.• Ionisation flame control appliance stops gas

flow when there is no flame and provides

for an alarm signal.• Limit safety thermostat with manual reset

acting on flame control appliance supply;reset by acting on selector off. It is enabled

at 105 ± 3°C.• Differential pressure valve acting on CH

circuit, switching burner off in case of water

shortage with capacity < 450 l/h.

• 3-bar safety valve on the heating system.• Differential pressure switch checking proper

operation of fan and combustion air suction

and exhaustion pipes.

SECTION 1Technical data

1.3Technical characteristics

• Flame continuous electronic modulation inDHW and CH.

• CH power pre-regulation device.• Electronic ignition with flame ionisation

control.

• Potentiometer to select CH temperature.• Potentiometer to select DHW water tem-

perature.• Pre-selection of slow ignition step.

• Off, DHW, DHW/CH selector and applianceunlock.

• NTC sensor to control primary temperatu-

re.• Circulator with CH air automatic bleeding

and separation device.• Heating circuit automatic by-pass.• Three-way valve with electric actuator and

flow-switch.• CH temperature and pressure control

thermal water gauge.• 8 l expansion tank.• Union plate to be connected to the system.

• Preparation for room thermostat and/or clock and local valve.

• CH filling device.• Braze-welded stainless steel exchanger

with limestone-proof device.• Appliance block signal.



9

Nominal heating capacity kWkcal/h

Nominal heating power kW

kcal/h

Reduced heating capacity CH kWkcal/h

Reduced heating power CH kW

kcal/h

Reduced heating capacity DHW kWkcal/h

Reduced heating power DHW kW

kcal/h

Electric power WSupply voltage V

Hz

CH operation - H2O max pressure bar

Max. temperature °C

EDHW operation - H2O max pressure bar Hot water quantity with 39 °C Ðt l/min

DHW minimum pressure bar

Selection field of DHW temperature °CSelection field of CH water temperature °CDHW minimum capacity l/min

L.P.G. nominal pressure (G 20) mbar

Liquid G.P.L. nominal pressure (G 30 - G 31) mbar

Pump: maximum head available for the system mbar at capacity l/h

Membrane expansion tank at capacity l

Hydraulic connections;

DHW input - output Ø”

CH input- output Ø”gas Ø”

Air suction - fumes exhaustion concentric pipes Ø mm

Maximum horizontal length m

Maximum vertical length m

Double system m Air fume separator m

Loss for elbow addition m

Wall crossing hole Ø mmFume capacity Nm3/h (max)

Air capacity Nm3/h (max)

Residual head (85-cm pipe) mbar

Residual head (tubeless boiler only) mbar Maximum CO without air p.p.m.

NOx s.a. p.p.m.

CO2

%

Minimum CO without air p.p.m.

NOx without air p.p.m.CO

2%

Boiler dimensions mm (H)

mm (L)

mm (P)Boiler weight kg

26,3

22.600

23,7

20.400

11,29.650

9,3

8.0009,8

8.450

8,1

6.950

125230

50

3

906

8

0,15

40÷7045÷86

2

20

29-37

380800

8

1/2”3/4”

3/4”

60-1003,4

5,25*

20+20**18+18**

0,8

10556,4

53,7

0,2

0,3580

130

5,5

150100

1,8

840

450

32244

1.4Technical characteristics

DESCRIZIONE

* Including 1.30-m long roof crossing end, not to be shortened

** The pipe alone must not exceed 25 m

UNITÀ C.S.I.




N U A L 1.5

Table of Law 10

Max heating power:

Useful kWFurnace kW

Conventional kW

Min. heating power:

Useful kW

Furnace kWConventional kW

Useful yield:

Max Nominal pressure %

Min. Nominal pressure %Reduced load 30% %

Max Nominal pressure:

Chimney losses with burner operation %

Skirt losses %Fumes temperature Ðt

Fumes capacity Nm3/h

Fume circuit residual head:

with flange (mbar)without flange (mbar)

Water content l

Max operating pressure bar Max Nominal pressure:

Combustion yield %CO

2%

Absorbed electric power W

22,7

26,323,1

9,3

11,210,4

90

83,784,2

9,1

0,9

12548

0,2

0,352,3

3

90,95,9

125

DESCRIPTION

1.6Overall dimensions (Fig. 1.1 - 1.2)

Fig. 1.1 Fig. 1.2

UNIT VALUE

WALL DRILLING



11

SECTION 2Description of main components

Fig. 2.1

LEGEND:

1 HYDRAULIC UNIT

2 CIRCULATOR

3 COMBUSTION CHAMBER AND HOOD4 FAN

5 VENTURI AND PITOT PIPE

6 AIR CASE

7 SAFETY PRESSURE SWITCH

8 EXPANSION TANK

9 HEAT EXCHANGER

10 MAIN BURNER

11 DETECTION AND IGNITION ELECTRODE

12 LIMIT THERMOSTAT

13 TEMPERATURE CONTROL SENSOR

14 CONTROL APPLIANCE

15 GAS VALVE

16 CONTROL APPLIANCE

OPTIONALHEATER




N U A L 2.1

Primary heat exchanger (Fig. 2.2)

The primary heat exchanger consists of an

oval-section coil with two pipes, located inside

a laminar pack increasing its heat exchange

surface.

Considering heat exchange intensity,

turbulators are located inside pipes to preventboth local water boiling and fluid layering and

also to prevent that exchange surface is not

fully used.

Shape of laminar pack is strictly connected

to the above; its density (distance between

sheets) allows to improve exchange surface,

without affecting fumes velocity (remember

that fumes flow is perpendicular to

exchanger), thus limiting load losses which

would affect exchanger yield. The transfer of

heat generated by combustion is performed

by heat exchange between fumes and

primary fluid flowing in the coil.The exchanger is fully coated by a lead-tin

alloy protecting it against corrosion.

Fig. 2.2

2.2Combustion chamber (Fig. 2.3)

The combustion chamber consists of a

properly curved sheet structure so that

ceramic-fibre insulating slabs can be inserted,

in contact with the inner surface. This material

has an operating temperature of about

1200°C and a melting point of about 1700°C.

For this reason, it is not affected by direct

contact with burner flame; in common use, it

is only affected by wrong mechanicaloperations.

Fig. 2.3

2.3Main burner (Fig. 2.4)

It consists of a series of stainless steel drilled

ramps, joined and properly spaced. Gas from

the valve flows through nozzles, then through

burner Venturi pipes, where it is mixed with

primary air; then, it flows out of ramps through

several openings and is burned. Air taken into

combustion chamber is used as secondary

air. Primary air is automatically dispensed

following nozzle diameter and it is not

necessary to adjust it during installation. The

routine maintenance of burner only requires

routine cleaning of gas outputs (nozzles)

when dirty. When obstructing burner nozzle,

also partially, different types of impurities

(putty, Teflon, spider webs, etc.) can provoke

bad combustion, with long and smoky flame.

Fig. 2.4



13

2.4Ignition and detectionelectrode (Fig. 2.5)

Two electrodes are installed on burner ends for flame detection to be signalled togas valve; these electrodes are fully

identical, under the structural point of view,but have di f ferent funct ions. The

electrodes, consisting of a metal core,have a ceramic outer coating electrically

insulated it.

The electrode, consisting of a metal core, has

a ceramic outer coating to electrically insulateit.

Metal end part is free from ceramic insulationand is located close to burner central ramp,at about 3 mm. Electrode must generate the

ignition spark and detect the flame on burner ramp.

Carefully check its proper position, since:• a contact point between electrode metal

end and main burner metal part does notallow flame signal

• electrode ground leak allows starting of

operating cycle, but stops it when safetytime has expired (9 ÷ 10 seconds)

• excessive distance between electrode andburner prevents flame detection andprovokes boiler shutdown.

Fig. 2.5

2.5Air box (Fig. 2.6)

The air box consists of four aluminium-sheet

parts assembled, with fumes sealing ensuredby neoprene gaskets. It contains all

components involved in combustion:flame ignition and detection electrode, burner,

combustion chamber, CH heat exchanger,fumes-conveying hood, fan, fumes pressure

gauge, heating sensor and limit thermostat.Thanks to sealed chamber, all componentsare completely insulated from surrounding

domestic environment. A compensation outlet is located on air box

bottom; this outlet is connected to gas valvepressure regulating device. On start-up, theoutlet allows stabilising membrane inside the

regulating device, by a small pipe. In this way,gas calibration is more accurate.

Fig. 2.6

2.6Circulator (Fig. 2.7)

The circulator located on boiler hydraulic

circuit return makes water circulation easier

during DHW or CH operation.

Fig. 2.7

7.0

6.5

6.0

5.5

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.00 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500

R E S I D U A L H E A D ( m C . A . )

SYSTEM CAPACITY (l/h)

H I G H - H E A D C I R C U L A T O R

S E R I A L C I R C U L A T O R




N U A L

2.7Expansion tank (Fig. 2.8)

It is a rubber membrane tank, with nitrogen

pre-charge under 0.8-bar pressure.N.B.: carefully check rubber compliance with

any anti-frost products poured in the heatingsystem.

The expansion tank balances volume

increase of primary fluid in a close (heating)circuit.

Its dimensioning is conceived to meet allsystem solutions normally used for single-

family heating systems. Should it not beenough for special installations, an auxiliaryexpansion tank can be added to the system.

Any check on ni trogen pressure insideexpansion tank has to be performed after

discharging heating system pressure. Theserial expansion tank has 8 litre capacity andcan operate with a system containing about

70 litres.

Fig. 2.8

2.8Hydraulic unit

The hydraulic unit is a single compact bodygathering all DHW and CH circuit functions.

It can be divided into three main sub-units:plate heat exchanger, three-way unit and

heating unit by automatic by-pass.

Heat exchanger (Fig. 2.9)

Fig. 2.9

The circulator is made of composite material

with built-in degassing device.

Technical characteristics of pump 15/50

(serial):

• supply voltage 230 V

• frequency 50 Hz

• current 0.42 A

• power 95 W

• condenser capacity 2µF

• revolution number 1700 RPM

Technical characteristics of pump

15/60 (high-head):

• supply voltage 230 V

• frequency 50 Hz

• current 0.51 A

• power 110 W

• condenser capacity 2.5µF

• revolution number 1750 RPM

A condenser is ho used insi de pump

connection box; it is very important for

circulator start-up.

Really, flowing of water quantity and head

inside the circuit requires an initial currenthigher than network current; thus,

condensator spark is necessary to rotate

pump motor on pickup and push water inside

the circuit.

Water inside pump body is circulated and

pushed to primary exchanger access by

impeller blades; impeller, submitted to

centrifugal force, tends to move towards the

side opposite to motor side.

At the same time, a depression is created

inside pump body requiring more water from

the circuit and starting circulation of primaryfluid.



15

1) Plate exchanger: it is braze welded,

consisting of a series of plates made of

stainless steel AISI 316, alternated with

copper plates. Each plate has beads (fluid

running channels) located in opposite

directions. Counter-current fluid flowing

makes heat exchange easier.

Contact points between two plates in

sequence are braze welded so that the whole

unit is involved in heat exchange

and a solid structure is obtained,able to resist to pressures up to

30 bars and temperatures about

180 °C. Duct system obtained in

this way allows fluid flowing (by

turbulent motion) ensuring an

optimal heat exchange.

Benefits of plate exchanger:

• limited dimensions, allowing,

with equal thermal flow, space

savings up to 90%, in some

cases, with respect to other solutions

• resistance to very high

pressures

• very low weight, al lowing

implementation of lighter hydraulic circuit

• higher breaking resistance in case of fluid

freezing, thanks to several inner welds.

2) Capacity limiting device: the capacity

limiting device reduces input water inflow to

secondary exchanger; it has a 8 l/min

calibration, thus it is white.

3) Check valve: located on primary water

input, it separates DHW exchanger from

primary circuit while heating. It consists of

a shutter and a 28-g pre-loaded spring.

4) Flow-switch (Fig. 2.10): device able

to detect water flow by a float consisting of a

Teflon shutter and a magnetic sector on the

upper part. When cold water flows in, a filter

protects flow-switch against impurities.

At the beginning, the flow is in quiescent

Fig. 2.10

position and inner contact is in opening

position. When water flows, float is raised

provoking sheets joining and flow-switch

contact closing; this contact electrically

enables circulator to start water flow to the

boiler.

Three-way valve (Fig. 2.11)

Fig. 2.11

The three-way valve consists of the following:

1) Shutter: it is cylindrical-cage shaped; a

flat gasket is located in the front part, while

the central hole houses three-way shaft. The

return-O-ring for DHW system is located on

mid-shutter.

2) Union and shaft: union drives andallows sliding of control shaft, ensuring safety

hydraulic valve sealing. During maintenance,

it is recommended to lubricate shaft by silicon

grease; if a union needs to be replaced,

carefully check shaft sliding surface and

replace the shaft in case of scoring.

3) Cap O-ring gasket: it ensures sealing

between cap and unit.

4) Cap: it closes all three-way hydraulic val-

ve components. It is made of plastic (pps)

and is fixed to the unit by six screws; the

stuffing union is screwed in the centre.

5) Three-way motor: 230-V motor; with

three electric terminals: neutral, DHW phase

and CH phase. The three-way valve, when

quiescent, is in DHW position. Switching from

DHW to CH hydraulic circuit is performed by

giving voltage to CH phase terminal. When

three-way valve shutter opens CH hydraulic

circuit and completely closes DHW circuit,

motor continues rotating for some degrees,

until a microswitch stops rotation by cuttingpower off.




N U A L

CH distribution unit (Fig. 2.12)

It is integral to hydraulic unit to make

maintenance easier. This component enablesmain burner ignition only when water circulation in CH exchanger is sufficient.

Really, burner ignition, also for few seconds,would be very dangerous when CH

exchanger is without water o water does notflow.

The distribution unit consists of the followingcomponents:

1) CH circuit automatic by-pass (Fig.

2.13): it consists of by-pass valve (similar tocheck valve used on primary circuit input of secondary exchanger) and its housing. Spring

is calibrated at 530 g. If high-head pump isused, it must be replaced by another spring,

with a higher load.

During normal operation, i.e. low loadlosses and, anyway, when water circulation

exceeds 450 l/h, automatic by-pass is notsubject to any stress on shutter spring,

Fig. 2.12

making primary fluid flow to CH system.On the contrary, if excessive load lossesexist on the system and minimum water quantity

required for circulation (450 l/h) cannot be ensured,

circulator unloads its head on

shutter surface, which movesenough to act on the spring

(overcoming its resistance),open communication with duct

(available on hydraulic unit)and connect system delivery to

return and start an inner re-circulation to be added to water quantity from system return.

N.B.: this mechanism isrelevant on high load losses

systems, which cannotensure proper appliance

operation. If, in hydraulicsystem, primary water tendsto re-circulate in the boiler,

valve can be replaced byanother one equipped with aspring standing for a higher

load. At the same time,Grundfoss 15/50 serial pump must be

replaced by a 15/60 high-head pump. Thesemeasures allow increasing water push to thesystem. Another successful usage is given

by systems equipped with thermostaticvalves or independent local valves controlled

by independent room thermostats allowingwater capacities variable in time according

to heating levels reached. Under normaloperations, with low load losses, the fluid,after f lowing through primary heat

exchanger, flows through the heatingsystems to get back to circulator.

2) Membrane: it is made of neoprene. Adevice existing on cover side (calibrated

depression flowing between membranefront and back part) allows depression

generated by circulator movement to affect

membrane back part, which inflates andpushes onto the pan, ensuring the release

of the shaft. This shaft closes safety micro-switch and starts-up boiler ignition.

Fig. 2.13

6) Three-way motor clip: it fixes valve

motor to three-way hydraulic unit.

7) O-ring: it ensures shutter tightening on

end-of-running with circuit in CH condition.

8) Shutter flat gasket: it ensures

tightening on DHW exchanger in CH

condition.

9) Shutter O-ring gasket: ensurestightening on CH side in DHW condition.

10) Spring: it loads shutter during CH

function.



17

3) Pan with shaft and spring: a pan,located on membrane outer side, with controlshaft housing in its centre, allows to transfer

strength applied onto the membrane by water circulating inside primary circuit. This pan

develops on the whole surface in order toconstantly exploit strength applied andtransfer it to the shaft, which is driven by head

union screwed into the cap. To make shaftsliding easier, a spherical housing is located

in the pan centre and the shaft coupling endis a semi-sphere; in this way an articulation

is obtained, allowing, independently of mem-brane position, free sliding inside the union. A spring is located between cap and pan

making membrane positioning easier, whenquiescent, with boiler off (circulator stopped).

During maintenance, it is recommended tolubricate shaft with silicon grease and, if aunion needs to be replaced, to carefully check

shaft sliding surface and replace it in case of scoring.

4) Cover: it houses membrane tighteningside. Depression outlet is located inside it by

machining in the unit. The external part hasa threaded blind hole to fix safety micro-

switch.

5) Union: it drives and allows control shaftsliding, ensuring sealing of safety hydraulicvalve. Union is different from three-way val-

ve union, as it has a flat-head end.

6) Safety valve: it protects hydraulic circuiton heating side from any overpressure

provoked by fluid volume increase in thecircuit. The safety valve switches main burner off when steam produced obstructs or

excessively slows water flow. With referenceto standard concerning product indu-strialisation, safety valves used on appliances

with potentiality < 34.8 kW open at 3-bar pressure.

7) Filling cock: it connects DHW circuitwith CH circuit to load or top them up.

2.9Gas valves (Fig. 2.14)

The gas valve supersedes burner ignition,adjustment and control. Industrialisation of this component provides for strict checks to

ensure maximum safety.This valve consists of an aluminium die-

casting containing two solenoid valves on gasinput, mechanically in series, but electricallyin parallel. The valve is also equipped with

two electrically-powered operators,electrically in parallel and mechanically in

series, in order to ensure higher safety level.The modulator is integral to gas valve;

modulation is performed by voltage variationto operator coil, which, at its turn, gradually

Fig. 2.14

opens - electromechanically - sending theright gas quantity to the burner. Thesemeasures, also required by standards, ensure

that - in case of malfunction - gas inflow tothe burner is stopped quickly. Ignition is only

allowed after restoring safety measuresrequired. Modulation adjustments areinserted in gas valve.

2.10Controlling appliances(Fig. 2.15)

The control appliance operates to performignition and flame control to the burner. It is

also directly connected to the gas valve bymale-female connection.

For ignition, a HT high-voltage generator -allowing cycle start-up - and a flame-detectioncircuit - exploiting ionisation - are contained

in the appliance. Under normal conditions, air

Fig. 2.15




N U A L

Fig. 2.16

2.12Venturi and Pitot pipe(Fig. 2.17)

Two devices are located on combustion gasexhaustion union.The former, named Pitot pipe, measures

impact pressure. The latter is a calibrated-section Venturi, signalling pressure value

when burnt gases flow. By connection topressure gauge, they act on its membraneand activate microswitch inside it, constantly

venturi

Pitot pipe

Fig. 2.17

2.13Limit thermostat (Fig. 2.18)

It prevents water in the boiler from boiling(temperatures exceeding 100 °C). It is a

contact thermostat, with automatic release.Thermostat sensor is located on delivery

ramp; it operates in order to stop electriccircuit of ionisation control appliance whenwater temperature inside main exchanger

reaches values close to boiling temperature.Block pilot light is on after its activation.

Activat ion temperature is equal to 105 ±3 °C.

Fig. 2.18

2.11Boiler feeder (Fig. 2.16)

The feeder is the component managing andchecking boiler adjustment function.It contains maximum/minimum CH trimmers,

as well as jumper to cut CH timing off.

block pilot

is a good insulating device, but, in special

conditions, atoms it consists of get someelectrons free; these electrodes make it an

excellent conductor. This phenomenon iscalled ionisation and is due to atoms which,after losing some electrons, are electrically

charged.CVI-M control appliance is equipped with a

trimmer to adjust slow ignition.

checking proper operation of air/fumes circuit.In order to check depression in combustionchamber, a depression meter must be

inserted, between Venturi, Pitot pipe and

pressure gauge. ÐP value, when cold, with

80-cm coaxial unload is 1.5 ÷ 1.6 mbar; with

coaxial, but also with maximum lengthallowed (3.4 m) it is 1.1 mbar.



19

2.14Fan (Fig. 2.19)

Expressly conceived for this type of appliance, it is completely silent and highlyperforming. The steel impeller is dynamically

balanced and directly connected to drivingshaft by a galvanised steel hub and a

hexagonal-head screw.Routine checks of internal impeller cleaning andmotor external parts, together with normal

maintenance on the boiler, ensure long-termoperation. Replace in case of mechanical

noises due to dragging or contact with externalcase.

Technical characteristics of fan FIMEGR0005:

• power voltage 240 V.• frequency 50 Hz.

• motor revolution number when impeller isoff 2250 RPM

• motor revolution number when impeller is

on 1850 RPM.

Fig. 2.19

2.15Safety pressure gauge(Fig. 2.20)

It is used for boiler control and safety, as itensure fan and fume exhaustion properly

operation. It consists of a silicon-rubber membrane, inside a double case. In caseof malfunction, by pressure change, the

membrane act ivates a microswitch,interrupting gas delivery from gas valve

main shutter.Calibration:

ON (contacts C-NO) 0.75 - 1.05 mbar-increasing pressureOFF (contacts C-NC) 0,8 - 0,65 mbar-

decreasing pressureCalibration field used:

40°C to 88°C.Two-wire electric connection sends an electricsignal to the board; this signal allows checking

fan efficiency and state in any moment.

Fig. 2.20




N U A L 2.16

NTC control sensor (Fig. 2.19)

NTC sensor - Negative Temperature Control,is a thermistor which, when temperatureincreases, decreases its resistance value.

The modulation circuit considers resistancevalue set on CH or DHW potentiometer; after

comparing value set and value measured by

NTC sensor (following supply currentcrossing them), the relevant signal returns to

the board; datum is processed, changingvoltage value sent to modulating coil.

In brief, when primary or secondary tempe-

rature increases, coil current value decreases,

modulating gas pressure to the burner.

The submersed sensor is located on deliveryramp, on primary exchanger output; it

instantly compares water effective tempera-ture and temperature set by user. The tem-

perature range used is 40°C ÷ 90°C.

If NTC sensor is electrically disconnected or

short-circuited, boiler and fan remain off, while

the circulator continues operating.

0 20 40 60 80 100

2000

4000

60008000

10000

12000

14000

16000

18000

20000

22000

24000

26000

28000

30000

32000

34000

0

RES ISTENZA NOMINALE

RES ISTENZA MINIMA

RES ISTENZA MAS S IMA

TEMP ERATUR A (°C)

Fig. 2.19

NOMINAL RESISTANCE

MINIMUM RESISTANCE

MAXIMUM RESISTANCE

R E S I S T A N C E

k w

TEMPERATURE (°C)



21

3.1Hydraulic operating princi-ple in DHW (Fig. 3.1)

When service water taking cock (1) is

opened, system water flows back to DHW

input (2), through capacity regulator (3) and

flow-switch (4). Water getting through the

SECTION 3Description of operating principles

Fig. 3.1

flow-switch, exceeding a 2 l/min capacity,

pushes float, located inside it, upward. This

movement allows to close the electric

contact, located in a device out of the flow-

switch. By a connection ramp (6), water flows

from flow-switch to flow limiting device

(5)(white-coloured: 8 l/min) then intosecondary exchanger (7).

CH

RETURN DELIVERY

DHW

OUTPUT INPUT




N U A L 3.2

Electric operatingprinciple in DHW (Fig. 3.2)

In order to get hotwater ready only, insummer, set function

selector on DHWsymbol. Considering

that the three-wayvalve is in DHW

quiescent posi t ion(quiescent = no heatrequested), when hot

water cock is openedand capacity exceeds

2 l /min, the f low-swi tch, measur ingwater flowing through

the circuit, feeds thecirculator by electric

enabl ing. Pr imary

circuit proper circu-lation is checked by

CH hydraulic valve,contro l l ing safety

micro-switch, which,hydraul ica l ly con-

nected, feeds, whenenabled the fan,while, when pressure

gauge is enabled, gasvalve operators are fed. Under tempera-

ture request condition, the burner switcheson and gas solenoid valve proportionally

opens shutter to allow slow burner ignition(automatically adjusted by CVI-M), thenmaximum power is reached until tempe-

rature set on selector is obtained.DHW temperature selector allows choosinga temperature between 54,5 ± 2,5 °C and

83 ± 2,5 °C. According to taking capacity,burner flame automatically fits hot water

requests. When low capacity of water istaken and temperature selector is idling or boiler is fed by pre-heating water, the burner

switches off 7 °C after temperature set andswitches on 1 °C below.

DHW water in modulation phase can oscil-late by ± 1 °C, maximum, 5 ± 1 °C when

off. Both temperature selector and sensor provide for a resistance value (ohm) toboard integrated component, which, at the

beginning (cold) controls burner maximumoperation, unti l temperature read on

secondary by NTC sensor, compared bymain board integrated component, withresistance set on DHW temperature

selector, approaches temperature set: :then minimum level is reached in

modulation phase and switches off when

temperature is reached.The modulating coil on the gas valve,

reaches a lower or higher current valuedepending on value measured by sensor

Fig. 3.2

and by the same resistance value set onselector, until burner switches off as tem-perature is reached.

Flow-switch

Circulator

Micro-safety device

Quiescent pressure gauge

Fan

Enabling pressure gauge

Burner (Ignition-control gas valve)

Finally, when DHW cock is opened, theoperating sequence is the following:



23

Fig. 3.3

CH

RETURN DELIVERY

DHW

OUTPUT INPUT

3.3Hydraulic operatingprinciple in CH(Fig. 3.3)

When temperature is requested by roomthermostat, the three-way electric valve is setto flow primary water into CH circuit. When

request is set on CH side, circulator (A) is

fed, generating a depression on return (R),affecting front part of safety hydraulic unitmembrane (C). At the same time, water, pushed into primary

exchanger (D) by circulator, flows along theconnection ramp to check valve (E) of DHW

exchanger; being this valve close becausethree-way valve is in CH position, it cannotovercome spring resistance and the flow

continues to system delivery.Pushed by circulator, water in the system

flows through primary exchanger (D), andreaches a pressure acting on membrane back

side (F); then, thanks to depressiongenerated by circulator, the membrane

moves activating the exit of safetymicroswitch control shaft. In this way, burner ignition is started up.

During normal operating conditions, i.e. low-load-loss system or water circulation

exceeding 450 l/h, the automatic by-pass (G)is pushed by shutter spring in directionopposite to safety membrane direction; then

water flows directly to the heating system(system delivery).

On the contrary, if relevant load losses existon the system, the circulator unloads its head

onto the by-pass shutter surface (I); the by-pass pushes the spring connecting return anddelivery by duct (H) and internal recirculation

is obtained, to be added to water coming fromsystem return.




N U A L 3.4

Electric operatingprinciple in CH(Fig. 3.4)

When selector is in DHW/CH position, withroom thermostat request, the three-way val-

ve is set to heating and circulator is activated.By heating membrane unit, proper water

circulation is checked and burner ignition isnot enabled in case of no circulation or insufficient capacity.

Now, if primary water temperature read byNTC sensor located primary exchanger

output ramp is lower than temperature set onthe control panel, the relay (RY1) is supplied

and, by safety microswitch (MS), enables thefan. Fan movement generates pressure anddepression, repeatedly read by Venturi and

Pitot pipe, acting act on the pressure gauge,which, closing internal electric circuit, enables

gas valve operators and, at the same time,

starts up ignition by CVI appliance.Gas solenoid valve proportionately opens theshutter, to allow slow ignition of the burner;

the burner operates at maximum power untiltemperature set on the boiler temperature

selector is reached, to be adjusted between40 ± 2.5 °C and 84 ± 2.5 °C.Shutdown is activated when temperature set

on boiler temperature selector plus 6 °C isexceeded, unless room thermostat is

activated when temperature set by the user is reached.When CH selector sets temperature, the main

board automatically adjusts power to systemrequest. If, when idling, power supplied

exceeds temperature required (as checkedby measuring temperature on primary by NTCsensor), the main board shuts the burner

down and allows its re-ignition only after aminimum time equal to 3' ± 30". Delay before

re-ignition only appears after appliancethermostat relay is activated (RY1). Noactivation is delayed for the following: general

switch, room thermostat, micro-safety, three-way micro. DHW taking cancels CH timing, if

existing.

Briefly, when DHW cock is closed, theoperating sequence in CH position is thefollowing:

Fig. 3.4

Room thermostat enabling

Circulator

Micro-safety device

Quiescent pressure gauge

Fan

Enabling pressure gauge

Burner (Ignition-control gas valve)



25

4.1Equipment

When delivered, this appliance is packed in

a cardboard box, with wide holes for

transportation.

It contains: warranty, instruction manual, pre-

installation template, connection kit.

The fumes exhaustion kit is delivered in se-

parate packages (optional).

4.2Unpackage

Place the package on the floor, with writing

oriented upward. Open both sides of the box.

Do not use a knife.

SECTION 4Installation of appliance

Fig. 4.1

Remove the package by placing the frame

on a support plane. Remove two polystyrene

blocks above and under the boiler. Remove

the template from the polystyrene block which

protects the panels.

Take out the box containing the installation

kit in polystyrene lower side, as well as the

cover for boiler unions.

The installation kit (Fig. 4.1) contains:

• installation template, to show fastening

holes posi t ion of upper and lower

supports.

• connecting unions: 2 CH water elbows, 2

DHW elbows (only C.S.I.), 2 biconic

unions 3/4", 2 biconic unions 1/2", 1 gas

cock, 1 DHW cock, water and gas seals.

CH DELIVERY 3/4”

CH RETURN 3/4”

HOT WATER 1/2”

COLD WATER 1/2”

CH COCKS (UPON REQUEST)




N U A L 4.3

Union plate installation(Fig. 4.2 - 4.3)

The union plate

consists of two parts;

the lower part is the

reference plate for

pipe distance between

centres,the upper part is used

to hook boiler to the

wall. The distance

between two plates is

defined by plastic

band included, which

is to be removed after

pre-installation.

Fix the union plate to

the wall by using the

two pre-set holes, as

shown in fig. 4.2;

carefully checkhorizontal level by a spirit level.

Locate boiler support plate following this

operating sequence:

• insert two template tags in rectangular

holes set in the final part of plastic band,

and close tags;

• place the support plate by a spirit level to

check its horizontal level;

• mark all manual fixing points by a punch;

• remove plastic and drill;

• insert two screws M6x45 supplied in theproper holes (with tiles, block the two screw

with nuts M6);

• fix the plate to the wall by proper inserts;

• fix the support plate, remove the plastic

band;

• install the boiler on the support plate and

fix by using nuts and washers supplied.

On the basis of the fumes exhaustion chosen,

it is necessary to make a hole in the wall (or

more holes, for separate system) having

dimensions suitable to duct diameters.

WARNING:

- All details about fumes exhaustion systems

are widely described in FUMES

EXHAUSTION technical manual.

- Fix the template on a vertical smooth wall.

- Install the boiler on a fire-proof wall.

If impossible, the wall must be protected

by a coating of fire-proof material.

If this appliance is used in buildings with

wooden structures, apply it in compliance withregulations in force. In case of doubt, contact

the competent gas supply body.

Fig. 4.2

Fig. 4.3

4.4Connection of gas supply

The gas canalisation is outdoor; if the pipe

crosses the wall,

it must get through the central hole of lower

plate. Connect a 15-mm diameter pipe to the

service gas cock and tighten the connection

nut to fasten cock to the appliance.

Ideal seal of unions is obtained by applying a

driving torque between 1÷2 kgm.

TEAR

CH RETURN 3/4”

CH DELIVERT 3/4”

HOT WATER 1/2”

COLD WATER 1/2”



27

4.5CH delivery and returnconnection(Fig. 4.4)

Connect CH pipes to 3/4" unions, delivery on

the right side, return on the left side of the

system. Fix nuts at a driving torque between

1÷2 kgm.

4.6DHW delivery and returnconnection (Fig. 4.4)

Connect DHW pipes to 1/2" unions, connect

loading cock on cold water inlet (supplied).

Fix nuts at a driving torque between 1÷2

kgm.

Fig. 4.4

4.7Safety valve exhaustionconnection

The safety valve, regulated at 3 bars, is builtinto circulator suction union. It is

recommended to set, under the safety valve,

a water collection connection with its bleed,

in case of leak due to overpressure.

This valve is also equipped with 1/2" threaded

outlet to connect an exhaust pipe.

During connection, check exhaustion position

allows water drain, also hot water, without any

damage or problems. Anyway, this drain

system must be located in a clearly visible

position.

4.8System washing

Close CH system cocks, if existing, as well

as cold water inlet cock.

If no system cock exists, close water general

cock, take a water supply pipe and connect

to CH return; then, locate a drain duct on CH

delivery, start water flow and let it leak until

clean water starts leaking.

Empty the system by bleeding caps in the

lower parts, close caps and connect system

cocks or ramps.

Load CH system.

4.9CH system loading

The expansion tank (8 - Fig. 2.1) is loaded

before at 0.8-mbar pressure and is

dimensioned to meet water volume in CH

circuit accounting for about 70 l. System is tobe filled at about 1 bar.

Anyway, do not exhaust nitrogen from CH

expansion tank. System cold filling

is to be performed by its cock, checking on

thermal water gauge that pressure is kept at

about 1 bar.

4.10Outdoor installation

This boiler is not designed for outdoor installation without any cover, but this

installation can be performed if special

measures are adopted.

Do not definitely submit the boiler to

atmospheric agents, such as wind, humidity,

frost, which could seriously affect its

operation.

In case of improper installation, warranty is

automatically invalidated.

Anyway, for outdoor installations a cover

technical area must be set for protection.

NUT

NUT

COPPER PIPE

NIPPLE

PIPE FASTENER

WASHER

SYSTEM




N U A L

5.2Electric connection toboiler (Fig. 5.1 - 5.2)

Access to electric connection terminal board

is allowed by the following instructions andas shown in the figures:

• untighten dashboard fastening screws(1).

• rotate dashboard downward.• insert power cable in the proper chock (2).• unt ighten terminal board cover (4)

screws (3), remove and make

connections.

Refer to electric diagrams in the next pagefor proper electric connections, as well as to

connect the room thermostat or the clock.Current power cable from switch and

terminal board must be flexible, with three0.75-mm cables, in compliance with tablesin force. Appliance input cable must be able

to stand for a contact with hot surface, upto 90°C. The power cable is connected to

the terminal board by phase cable to L-marked terminal, neutral cable to N-marked

terminal and green/yellow ground cable toterminal marked with ground symbol. Do notconnect other terminals to this terminal

board. When operations are completed,tighten fixing screws of terminal board cap

and re-install the dashboard.

Fig. 5.1

Fig. 5.2

5.1General

The connection to electric network must be

performed by bipolar switch with minimum3-mm opening to contacts. When

connect ing, comply with l ine-neutralpolarity. The appliance operates with 230V alternate current, 50 Hz, 125 W electric

power and complies with standard CEI 61-1 EN 60335-1. Connection with safe

grounding is compulsory, in compliancewith regulations in force. Using gas or water pipes as electr ic appl iances

grounding is strictly forbidden. For electricconnection, a cable type IMQ HAR H05V

V-F UNEL 35746 3 G 0.75 - 3 x 0.75 mm,with maximum outer diameter equal to 7

mm. During cable connection for external

controls, do not interfere with harnessinside the appliance and installed in shop.

It is fundamental that all external controlcircuits and harness are generated from

the same electric insulator of the appliance.The Manufacturer is not responsible for damages provoked by non-respect of the

above-mentioned advises.

SECTION 5Electric connections



29

5.3 Electric connections

Basic connection

When installing the clock, connections must be as shown in the figure. Contact operates

at 230 V.

When installing the room thermostat, connections

must be as shown in the figure. Contact operates at

230 V.

When installing the clock and the room thermostat,connections must be as shown in the figure. Contact

operates at 230 V.

Roomthermostat connection

Clockconnection

Clock and roomthermostat connection

T O B

O I L E R

T O B

O I L E R

T O B

O I L E R

T O B

O I L E R

b l u e

w h i t e - r o u g e

b l a c k

r o u g e - b l a c k

b l u e


b l a c k





N U A L

NOTE: L-N POLARIZATION IS COMPULSORY

0 BOILER OFF

E SELECTOR IN DHW POSITION

I SELECTOR IN CH POSITION

T.A. ROOM THERMOSTAT

P.F. FUME PRESSURE SWITCH

T.L. LIMIT THERMOSTAT M.S. NO-WATER MICRO-SAFETY

SAN DHW REQUEST FLOW SWITCH

L1 BLOCK SIGNAL LIGHT

S1 PRIMARY TEMPERATURE (NTC)

SENSOR

P.T.R. CH TEMPERATURE SELECTION

POTENTIOMETER

P.T.S. DHW TEMPERATURE

SELECTION POTENTIOMETER

R.R. CH POWER ADJUSTMENT

R.M.R. CH MINIMUM POWER

ADJUSTMENT

F1 2 A F FUSE

E.A. IGNITION ELECTRODE

E.R. DETECTION ELECTRODE

3V THREE-WAY ELECTRIC VALVE

P PUMP

V FAN

S.C. BOARD ON DASHBOARD

S.V. BOARD ON GAS VALVE

RY1 TEMPERATURE RELAY

RY2 PUMP RELAY

RY3 THREE-WAY RELAY

NOTE: L-N POLARIZATION IS COMPULSORY.

The room thermostat is to be connected between terminals 1 and 3 after removing the jumper.

Room thermostat contacts must be dimensioned for 230 V. A class II thermostat only can be used.

5.4 Multi-wire electric diagram

5.5 Operating diagram

b l u e

b r o w n

b l u e

w h i t e

b l u e

b r o w n

b l a c k

D H W

C H

white-black

white-black

DHW

b r o w n

b l u e - b l a c k

v i o l e t

v i o l e t

b l a c k

w h i t e

o r a n g e

v i o l e t

v i o l e t

o r a n g e

b r o w n

b l u e

b l u e - b l a c k

r o u g e


o r a n g e

o r a n g e

r o u g e



w h i t e - r o u g e w

h i t e - b r o w n

white-brown

b r o w n

b l u e

b l a c k

b l u e w h i t e

g r e y

g r e y

r o s e

r o s e



31

5.6 Position of adjustment potentiometers

R.R.

R.M.R.

5.7 Connection to accessories

LOCAL VALVES CONNCECTING DIAGRAM

Standard system

System with timed relays

POTENTIOMETER

BOILER

BOILER




N U A L

LEGEND

1 FILLING COCK 2 CH MEMBRANE UNIT

WITH AUTOMATIC BY-PASS

3 SAFETY VALVE

4 3-WAY ELECTRIC VALVE

5 CIRCULATION PUMP

6 DHW EXCHANGER (only C.S.I.)

7 AIR BLEEDING VALVE

8 DETECTION ELECTRODE

9 FAN

10 PRESSURE TAKING TUBE

11 DEPRESSION MEASURE PIPE

12 AIR FLANGE

13 DIFFERENTIAL PRESSURE SWITCH

14 EXPANSION TANK

15 MAIN EXCHANGER

16 MAIN BURNER

17 IGNITION ELECTRODE

18 LIMIT THERMOSTAT

19 FLAME CONTROL APPLIANCE

AND GAS VALVE

20 DHW SHUTTER COCK (only C.S.I.)

21 APPLIANCE SHUTDOWN PILOT LIGHT

22 FUNCTION SELECTOR

23 CH TEMPERATURE SELECTOR

24 DHW TEMPERATURE SELECTOR

(only C.S.I.)

25 THERMAL WATER GAUGE

26 CLOCK CAP

Fig. 6.1

SECTION 6First ignition modesPreliminary operations



33

6.1General

Check pressure in gas network is sufficient,

13.5 bars, minimum. Also consider that boiler only operates if water circulation in heatexchanger is sufficient. Before ignition, check

the boiler is set to operate with gas available.The type of gas is specified on boiler package

and on characteristic data tag applied on the

boiler. If a pre-existing system is used, it isrecommended to thoroughly wash all pipesto remove any residues possibly affectingappliance proper operation. In order to access

to electric, hydraulic and gas parts of theboiler, push the dashboard forward, as shown

in figure 6.2.For more information about disinstallation,refer to section 8.

6.2Gas supply

To install gas pipes, follow detailedinstructions in standards UNI-CIG 7129, 7131and relevant updates. For a complete

reference to the relevant standards, refer tovolume “Laws and standards” properly set by

Beretta Caldaie.

For further information also refer to paragraph4, section 4.

6.3Sealing components

Some boiler organs can be damaged by

impurities in the heating system on ignition.It is recommended to disconnect the boiler

from hydraulic system when starting it up,check it is cleaned and wash the system. It isalso recommended to check blocks on

delivery and return on CH side are opened.If boiler external controls are connected

Fig. 6.2

(sensor, room thermostat, chronothermostat,etc.), ensure they are in the CH requestposition. It these accessories are installed,

the jumper, which cancels ignition enablingby external controls, can be placed on

terminal board TA contacts, to make operationsetting more rapid. This jumper is installed inshop on all models without external controls.




N U A L

7.1Operations for boiler ignition and use

Ignition(FIG. 7.1 - 7.2)

Open the gas cock by rotating the knobunder the boiler counter-clockwise, to allow

fuel flow.

SECTION 7First ignition and adjustmentprocedure

Fig. 7.1

Place function selector on symbol «

» or « » following the operation

selected.

Fig. 7.2

CH operationCH operationCH operationCH operationCH operation(FIG. 7.3 - 7.4)For CH use, place function selector on symbol

« » (CH). Boiler is activated to pro-

duce heating and domestic hot water

(bathrooms, kitchen, etc.).

N.B. If a clock is installed, it must be on “On”position.

Rotate knob with symbol « », to adjustCH water temperature .

Fig. 7.3

Fig. 7.4

openingposition



35

DHW operationDHW operationDHW operationDHW operationDHW operation(FIG. 7.3 - 7.4)FOR DHW use, place function selector on «

», i.e. the boiler only produces domestic

hot water (bathrooms, kitchen, etc.).

Fig. 7.5

Rotate knob with symbol « », to adjustDHW temperature.

Fig. 7.6

Block pilot light(Fig. 7.7)If the boiler does not switch on within 9-10seconds after ignition spark, the appliance

shuts down and the red pilot light switcheson. The same pilot light also switches onwhen limit thermostats activates. To reset,

follow the steps below for unblocking.

Release function

In order to restore initial conditions, takefunction selector on “0”, then to the positionrequired, checking pilot light is off. After

necessary operat ions have beenperformed and correct operating logic is

restored, the boiler automatically startsagain (also refer to sect ion 9,troubleshooting).

Shutdown(Fig 7.8 - 7.9)

For complete shutdown, take selector knob

to symbol «0».

Fig. 7.8

In case of long absences, close gas cockknob under the boiler.

Fig. 7.9Fig. 7.7 block pilot light

close cock




N U A L Check (Fig. 7.10 - 7,11)

During operation, the water gauge on

BOILER dashboard must show, when systemis cold, pressure values between 0.6 and 1.5bar (blue-coloured scale), to avoid system

noise due to air.If water circulation is not sufficient, the boiler

stops. Water pressure must never be lower than 0.5 bar (red field).

Fig. 7.10

Fig. 7.11

7.2Gas transformation, cali-bration and adjustmentprocedures(Fig. 7.12)

Shifting from a gas to another, belonging to

another group, is easy also when the boiler is already installed. For the relevant pressure

values, refer to “MULTIGAS” table on page38.

OPERATIONS TO PERFORM ON THEBOILER AND ON THE GAS VALVE TOSHIFT FROM GAS G20 TO GAS G31AND VICEVERSA

Stop boiler voltage and close gas centralcock.

Replace burner nozzles as follows:• remove boiler skirt and cover of air

chamber;

• remove combustion chamber front cover;• remove burner unit by untightening screws

(A) fixing it to gas manifold (fig. 7.12).

Now, replace nozzle with manifold installed

on the boiler; install nozzles using newgaskets available in the transformation kit.

Carefully check nozzle cleaning: also a partialobstruction would seriously affectcombustion.

Carefully re-assemble the whole unit.

Fig. 7.12

If this happens (for example because of system losses or repeated air bleeds), restore

pressure by opening filling cock under theboiler as long as necessary and, at the sametime, checking pressure on water gauge.

Before performing the above-mentioned

operation, it is recommended to place generalfunction switch on symbol «0». If pressuredrops are too frequent, losses in heating

circuit must be identified.

BLIND PLATE



37

If shifting is to LPG, remove propagationdeflector on burner unit. Refer to fig. 6.19 and

act as follows:

a) Gas propagation front grid:• place grid on the burner and fasten by

screws (D) available;• insert plates (C) in grid slots, in

correspondence with ignition and

detection electrodes;

• re-install the burner and tighten four screws (A).

b) Air protection rear grid:

• untighten manifold upper screws (B);• insert grid between manifold and air

case;• rotate grid by 90° and locate so that slots

(E) are inserted between heads of screws (B) and manifold;

• tighten screws (B).

7.3Pressure calibration on theburner, preliminary checks(Fig. 7.13)

Fig. 7.13

Use a (digital or column of water) pressure

meter, as well as a small and a big cutscrewdriver, to calibrate and check. Act as

described in the following (fig. 7.13).

• connect water gauge to pressure outlet (B)upstream of gas valve;

• check that static pressure, with boiler off,does not exceed the limit value of 50mbar;

• switch-on the boiler;• enable DHW operation by dashboard

controls;• select maximum DHW temperature value;• fully open DHW cock and check, by water

gauge connected, that gas dynamicpressure is not below the following values:

- 15 mbar for methane- 37 mbar for LPG

• disconnect water gauge and close outlet(B).

7.4Pressure calibration on theburner (Fig. 7.14)

• untighten dashboard fastening screws;• rotate the dashboard forward;

• remove board cover, untightening twofastening screws;

• use a differential pressure gauge;• disconnect gas valve compensation intake;• connect a pressure gauge end to pressure

intake (A) downstream of gas valve;connect the other pressure gauge end to

compensation end on air case;• remove aluminium cap from gas valve ser-

vo-regulator (D);

• select, by dashboard controls, CH andDHW maximum water temperature.

Fig. 7.14

R.R.

R.M.R.

AIR CHAMBER

POTENTIOMETER

VIEW FROM X




N U A L

Liquid gas

PARAMETERSpropane

(G 31)butane(G 30)

Methane(G 20)

Lower Wobbe index

(at 15°C-1013 mbar)

Supply nominal pressure

mbar (mm H2O)

Supply minimum pressure

mbar (mm H2O)

Main burner:

10 nozzles Ø mm.

CH maximum gas capacity m3/h

kg/h

DHW maximum gas capacity m3/h

kg/h

CH minimum gas capacity m3/h

kg/h

DHW minimum gas capacity m3/h

kg/h

Slow ignition calibration pressure mbar (mm C.A.)

Maximum pressure downstream CH valve mbar (mm C.A.)

Maximum pressure downstream DHW valve mbar (mm C.A.)

Minimum pressure downstream CH valve mbar (mm C.A.)

Minimum pressure downstream DHW valve mbar (mm C.A.)

80,90

29 (295,7)

0,77

2,19

2,19

0,93

0,81

16,7 (170)

28,0 (286)

28,0 (286)

5,0 (51)

3,8 (39)

45,70

20 (203,9)

13,5 (137,7)

1,35

2,78

2,78

1187

1,04

4,0 (41)

10,1 (103)

10,1 (103)

1,85 (19)

1,45 (15)

70,90

37 (377,3)

0,77

2,15

2,15

0,92

0,80

16,7 (170)

36,0 (367)

36,0 (367)

6,5 (66)

5,1 (52)

Calibrate by measuring differential pressure between pressure intake downstream of gas valve and air case

compensation intake.

Mechanical idling

• Switch boiler on, placing function selector on CH;

• Rotate RMR and RR potentiometers,located on the board (fig. 7.15), counter-

clockwise.If operation is correct, the burner tends toswitch off.

Now, calibrate mechanical idling by rotatingadjustment screw (C) counter-clockwise, until

values specified in MULTIGAS table arereached.

Mechanical maximum value

Fully rotate RR potentiometer counter-

clockwise. Act on the plastic screw located under the

previously-removed aluminium cap to adjustpressure to maximum value until valuesspecified in MULTIGAS table are reached.

During calibration, check water temperaturein the boiler does not exceed 70°C and supply

pressure is within the following values: 20 ±

0.3 mbar at MTN and 37 ± 0.8 mbar a LPG.When the aluminium cap is re-positioned, thecompensating intake automatically activates;

then gas pressure can be reduced by about0.4 mbar from the initially calibrated value.

Slow ignition

Adjust by taking mass detection electrode

and, by slow ignition adjustment roller (L.A.Fig. 7.13) located in ignition board right side,

take gas pressure to the level required. It isrecommended to calibrate slow ignition during

decrease, starting from max position(clockwise), decreasing until the correctposition is reached (counter-clockwise

position). RMR idling potentiometer is notused.



39

HEATING SYSTEM POWER ADJUSTEMNT DIAGRAMS

0

1

2

3

4

5

6

7

8

9

10

11

12

13

6 8 10 12 14 16 18 20 22

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

6 8 10 12 14 16 18 20 22

Ã

Ã

Ã

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

32

34

36

38

6 8 10 12 14 16 18 20 22

N O Z Z L E S G A S P R E S S U R E

( m b a r )

N O Z Z L E S G A S

P R E S S U R E

( m b a r )

N O

Z Z L E S G A S P R E S S U R E

( m b a r )

GAS G20

USEFUL POWER (kW)

GAS G30

USEFUL POWER (kW)

GAS G31

USEFUL POWER (kW)




N U A L

8.1General checks

This boiler is to be delivered to the user only

after the first starting and the relevant checks

have been performed by qualified personnel.

In particular:

a) installation must comply with standards

UNI-CIG 7129-7131 and amendments

thereof (for gas system part) and with

standards CEI for electric components;

b) fumes exhaustion duct and the final part

must be installed in compliance with

instructions, in particular, with boiler on,

no combustion product can leak from any

seal.

For further information on types and

standards concerning fume exhausts,refer to FUME EXHAUSTION manual;

c) connect the boiler to 230 V, 50 Hz electric

supply by bipolar switch with minimum

3-mm contact opening; electric power

absorbed accounts for 125 W;

d) the safety valve inside the boiler must

never be blocked: activated it shortly for

this check;

e) after opening gas general cock, check no

leak has occurred on seals;

f) rotate function selector to CH functionand check room thermostat, programmer

and chronothermostat are enabled. If the

burner is not switched on, read section 9

(troubleshooting).

8.2Maintenance

In order to ensure boiler constant efficiency,

it is recommended to check its operation

regularly.

SECTION 8Maintenance

8.3Removal of boiler skirt(Fig. 8.1)

Remove two screws fastening the skirt and

extract it upwards.

Fig. 8.1

The frequency of these checks will depend

on installation and use conditions.

Perform routine maintenance once a year.

Before starting maintenance, disconnect main

power supply and boiler current intake (if

required); if an electric contact is used,

remove the safety fuse. Close gas supply

cock upstream of the boiler.



41

8.4Removal of air box frontcover (Fig. 8.2)

Remove front cover by untightening six

fastening screws. Inspect box seal; replace

it if damaged or worn.

Fig. 8.2

8.5Burner and ignition anddetection electrodes(Fig. 8.3 - 8.4)

Remove cover from combustion chamber by

untightening five screws (fig. 8.2). Untighten

the nut fixing the connection ramp between

gas valve and burner. Remove four screws

fastening the burner (fig.8.3) which is tilted

forward: extract and carefully place it on the

combustion chamber.

Fig. 8.3

Fig. 8.4

Untighten electrode fastening screws and

remove them carefully (fig. 8.4). Check

electric connections on control and regulation

appliances, with reference to electric

diagrams shown in section 5. Assemble following the reverse process.

8.6Burner nozzles(Fig. 8.5)

Brass nozzles are used and have different

sections, following the type of gas delivered:

MTN 1.35 mm - LPG 0.80 mm.

Transformation from a gas family to another one can be easily performed, also with boiler

installed.

Disinstall the burner as previously described.

Take the burner out to have access to gas

ramp and nozzles (fig. 8.5). Nozzles can be

easily replaced with manifold installed on the

boiler; install new seals available.

Carefully check that nozzles are not

obstructed, even partially, as this would affect

combustion.

Carefully re-install.

After insta lla tion, test sealing of all gas

connections.

Fig. 8.5




N U A L 8.7

Main heat exchanger (Fig. 8.6)

Remove CH main exchanger as follows:

• remove boiler skirt as described in

paragraph 8.3;

• remove air-tight case front cover as

described in paragraph 8.4;

• remove combustion chamber cover as


• remove two side panels of combustion

chamber;

• close any CH valves;

• close central cock if no CH valves are

installed;

• discharge hydraulic circuit inside the boiler

as follows:

- close network water inlet cock and open

filling cock of CH circuit;

- in this way, the DHW circuit is connectedto CH circuit and allows discharging water

in CH circuit from one of the lowest DHW

cocks on the boiler.

Disconnect two side ramps for hydraulic

connection (fig. 8.6): now, exchanger can be

taken out from its support slides.

During disinstallation, do not wet boiler

electric components.

When operations are completed, assemble

following the reverse procedure and using

new seals to connect hydraulic circuit ramps.

Fig. 8.6

8.8Fan (Fig 8.7)

Before removing the fan, the following is to

be removed:

• boiler skirt, as described in paragraph 8.3;

• airtight case front cover, as described in

paragraph 8.4;

• combustion chamber cover, as described

in paragraph 8.5;

• two side insulating panels of combustion

chamber;

• left side of air case, untighten screws

fastening fume hood fan is attached to and

screws fastening fume exhaust duct band.

When removing fume hood, carefully check

side air deflector which are fixed by the same

screws fastening the hood.

Now, after disconnecting the fan electric

power connector and extracting fumes

exhaustion duct, hood and fan are free.Untighten 4 fastening screws of fan to fume

hood and extract the fan scroll.

If fan is replaced, transfer aluminium fume

exhaustion elbow on the new fan.

Check seal between hood and fan and

replace it, if worn.

Assemble following the reverse process,

carefully positioning the aluminium elbow first,

with its fastening band.

When operations are completed, always

check proper positioning and seal of band.

Fig. 8.7



43

8.9Air pressure switch (Fig.8.8)

To remove air pressure switch remove the

following:

• boiler skirt, as described in paragraph 8.3;

• airtight case front cover, as described in

paragraph 8.4;

• screws fastening pressure switch to air

case (fig. 8.8).

Disconnect electric connections and silicone

pipes for pressure-taking and depression

detection.

Replace the pressure switch, install following

the reverse process.

Fig. 8.8

8.10Gas valve and control

appliance (Fig. 8.9)

Close gas supply.

Disconnect electric harness from gas valve.

Untighten seal union (wrench no. 29) to

burner gas ramp.

Untighten four cross screws fastening valve

support bracket.

Untighten seal union of gas blocking inlet

cock.

Now, remove gas valve and replace it, if

necessary, together with seals.

It is important to perform a sealing test withgas blocking cock open, in compliance with

standard UNI 7129/92 and amendments

thereof.

Fig. 8.9

8.11Combustion chamber insulating panels

Act as follows to remove combustion chamber

insulating panels:

• remove boiler skirt, as described in

paragraph 8.3;

• remove airt ight case front cover, as


• remove combustion chamber cover, as

described in paragraph 8.5;• remove two side insulating panels in the

combustion chamber;

• remove main heat exchanger, as described

in paragraph 8.7.

Now, access is allowed to rear insulation

panel, which can be removed by a

screwdriver.

The fourth panel, i.e. the front panel, is

fastened by beads to combustion chamber

cover.

After replacing damaged panels, instal l

following the reverse process.

To replace the appliance, act on the screw

fastening gas valve and take it out.




N U A L 8.12

Circulator (Fig. 8.10)

For circulator removal, first remove boiler

skirt as described in paragraph 8.3, then:

• close CH circuit delivery and return

valves, if installed;

• if valves are not installed, close general

cock;

• empty the hydraulic circuit;

• untighten connection unions to primary

circuit return rump, extracting the

fastening key;

• untighten the fastening screw of support

bracket;

• untighten connection union to hydraulic

unit.

• disconnect electric harness in circulator

terminal board and extract it.

Install circulator following the reverse

process, carefully replacing seals.Connect power to terminal board as

follows: line - L, neutral - N , yellow/green

- grounding.

It is necessary to remove circulator from

boiler, to check blower and motor; simply

remove 4 socket head screws fastening

motor and check.

Fig. 8.10

8.13Hydraulic unit (Fig. 8.11)

Preliminary operations

Operate as follows to remove and install thehydraulic unit:

• remove skirt as described in paragraph 8.3;

• stop electric power by bipolar switch or power intake;

• close network water inlet cock;

• open CH system filling cock.

Fig. 8.11

These three operations connect CH and DHWcircuits, allowing discharge CH side water inthe boiler from the closet DHW taking; ensure

that discharge taking is lower than boiler. If the system is set with any block cocks on

delivery and return, close them. Viceversa,the system will empty down to the taking point.Use a cross screwdriver to untighten

fastening screws of safety microswitches.

Unmounting of hydraulic unitUnmount connection ramps for easy access

to unit sub-assemblies and relevant operatingcomponents (flow switch, water distributionunit, three-way electric valve and CH

hydraulic unit. Use a 29-mm wrench todisconnect the ramp connecting to main

exchanger (1) and ramp connected tosecondary exchanger (2) and CH unit (3).Use a cut screwdriver to take the check val-

ve out of the secondary exchange connectionunion.

Unmounting of safety unit andautomatic by-pass (Fig. 8.12).Untighten three screws (1) on safety unit (2)cover by using a 7-mm hexagonal wrench.

Remove spring (3), cap (4) and take themembrane (5) out. Use a cut screwdriver toextract the by-pass unit.



45

Fig. 8.12

Fig. 8.13

8.14Expansion tank

Valve for nitrogen load and control is locatedin tank upper part. This tank, pre-loaded by a0.8-bar pressure, can stand for a system with

total water content accounting for about 70litres. Nitrogen pressure in expansion tank

must be checked whenever DHW water pressure is eliminated, i.e. when the systemis empty.

Replace the tank by untightening the nut of the ramp connected to the hydraulic unit and

the fastening screw connecting chassis; then,take it out upwards; assemble by following

the reverse procedure.

1

2

8.15Removal of safetymicro-switches

Block micro-switch and untighten screw

fastening the support bracket. Removeelectric connections.

After installing the new switch, assemble byfollowing the reverse procedure.

8.16NTC sensor (Fig. 8.15)

Empty water from boiler circuit, as describedin paragraph 8.13. Remove connection plug

to NTC sensor.Untighten NTC sensor from its seat on circuit

delivery ramp. Assemble by following thereverse procedure.

Fig. 8.15

8.17Feeder (Fig. 8.16)

Remove boiler control appliance by removing

knobs fastened to potentiometers. Reversethe dashboard forward, after untightening

fastening screws, disconnect appliance

electric harness. Untighten screws fasteningcover and two screws fastening the appliance;

take appliance out. Assemble by following thereverse procedure.

Fig. 8.16

Unmounting of DHW exchanger (Fig.8.13).Unmount secondary exchanger untightening

- by a cross screwdriver - the left tie-rod, (1fig. 8.13) fastening exchanger to the unit, and

the right tie-rod by a 7-mm socket wrench(2 fig. 8.13).




N U A L 8.18

Setting of combustionanalysis intakes (Fig. 8.17)

The air case is set to allow analysing thecombustion parameters without skirt removal.

Measure is performed by two sumps, locatedon air case upper

part, where sensorsto measure air tem-perature and CO

concentration arelocated, after

removing screw

plugs. The referencevalues are shown on

the table concerninglaw 10 on page 10.

Fig. 8.17

8.19 TABLE OF SCHEDULED ROUTINE MAINTENANCE

OPERATIONS TO BE PERFORMEDAFTER THE FIRST YEAR

1°year

2°year

3°year

BURNER CLEANING AND NOZZLE CHECK (REPLACE IFOBSTRUCTED)

PRIMARY EXCHANGER CLEANING (CALCIUM REMOVINGWASHING, IF NECESSARY)

FAN CLEANING, VENTURI AND PITOT; EXHAUST DUCT CHECK AND ASPIRATION AND TERMINALS RELATIVE

ELECTRODE CHECK AND CLEANING

SHAFTS CHECK AND LUBRICATION(REPLACE IF NECESSARY)

MEMBRANE AND STUFFING BOX CHECK (REPLACE IF

NECESSARY)

CHECK ON FILTER, CAPACITY LIMITING DEVICE, BY-PASS,

SEALS AND LOADING COCK

DHW START-UP CHECK WITH 2 l/min CAPACITY

EXCHANGER EFFICIENCY CHECK

CALIBRATIONS AND ADJUSTMENTS CHECK

CHECKS ON BLOCK SAFETY DEVICES, MODULATION,

OPERATORS CLOSING AFTER FLAME EXTINGUISHING

X X X

EXPANSION TANK LOAD CHECK

COMBUSTION ANALYSIS

4°year

FUMES AIR

X

X X XX

X X XX

X X XX

X X XX

X X

X X

X X

X X

X X

X X

X X XX

X X XX



47

SECTION 9Troubleshooting

This section shows flowcharts of boiler

operating tests.Refer to electric diagram in fig. 9.1 toidentify the components.

When referring to tests, consider that >means higher and < means lower.

Fig. 9.1

NOTE: L-N POLARIZATION IS COMPULSORY.

The room thermostat is to be connected between terminals 1 and 3 after removing the jumper.

Room thermostat contacts must be dimensioned for 230 V.

A class II thermostat only can be used.

b l u e

b r o w n

b l u e

w h i t e

b l u e

b r o w n

b l a c k

D H W

C H

white-black

white-black

DHW

b r o w n

b l u e - b l a c k

v i o l e t

v i o l e t

b l a c k

w h i t e

o r a n g e

v i o l e t

v i o l e t

o r a n g e

b r o w n

b l u e

b l u e - b l a c k

r o u g e


o r a n g e

o r a n g e

r o u g e



w h i t e - r o u g e w

h i t e

- b r o w n

white-brown

b r o w n

b l u e

b l a c k

b l u e w h i t e

g r e y

g r e y

r o s e

r o s e




N U A L TEST A

OPERATING TEST FOR BOILER START UP

BEGINNING

PLACE ROTATING

SELECTOR

ON DHW

AND SET DHW

TEMPERATURE

TO MAXIMUM

OPEN HOT WATER

AT CAPACITY >

2.5 l/min

noPUMP STARTS UP

THREE-WAY VALVE

IN DHW

POSITION

no

40VBETWEEN

TERMINALS x 4.16AND N ONCONTROL

BOARD

no

yes

no

no

A 2

A 1

CHECK

HARNESS AND

CONNECTIONS

OR DHW MICRO-

SWITCH

230VBETWEEN

TERMINALS x 2.3AND x 2.5 ON

CONTROLBOARD

CHECK

HARNESS AND

CONNECTIONS

FAN OPERATES

DOES PUMPOPERATE?REPLACEPUMP

yes

yes

no

no

no

yes

REPLACEFUSE

CHECK

FUSE ON

CONTROL

BOARD

230VBETWEEN

TERMINALS x 3.6AND 3.7 ON

CONTROLBOARD

230 V ON

TERMINAL L AND N

ON POWER TERMINAL

BOARD

CHECK BOILER

POWER ON

COUNTER

CHECK

HARNESS AND

CONNECTIONS

FUSE OK

yes

yes40VBETWEEN

TERMINALS x 4.15AND N ONCONTROL

BOARD

no

yes RETURN TO THE

BEGIN-NING OF

TEST A

230V BETWEEN

BLUE AND BLACKON THREE-WAYVALVE

yes

CHECK AND/ORREPLACEELECTRIC

THREE-WAYVALVE

230V

BETWEENTERMINALS x 1.1 AND

x 1.2 ON CONTROL

BOARD

nono

yes

yes

REPLACE

CONTROL

BOARD

REPLACE

CONTROL

BOARD

UNLOCK PUMP

BY ACTING ON

ROTOR BY A

SCREWDRIVER

230V

BETWEEN BLUE

AND BROWN WIRES

ON PUMP

no

yes

yes

no

yes



49

A1

CONTROL

BOARD DHW

THERMOSTAT

ACTIVATED

230VBETWEEN

TERMINALS x 3.8 AND x 3.9 ON

CONTROL BOARD

WAIT FOR HEAT

REQUEST BYCONTROL BOARD

DHW THERMOSTAT

MEMBRANE

UNIT SHAFT OUT OF

ITS SEAT?

CHECK MICRO-

SAFETY DEVICE

CONTINUITY,REPLACE IF

NECESSARY

230V

BETWEEN

TERMINALS x 3.11 AND

N ON CONTROL

BOARD

CHECK AND/OR

REPLACE

HARNESS

230VBETWEEN

TERMINALS x 3.12 AND N ON CONTROL

BOARD

REPLACE

CONTROL

BOARD

no

yes

no

yes

yes

no

yesno

no

yes

no

yes

yes

no

no

no

REPLACE

FLAME

CONTROL

BOARD

CHECK FAN HARNESS

AND CONNECTIONSREPLACE FAN

no

230VBETWEEN

TERMINALS x 3.10 AND N ONCONTROL

BOARD

yes

230V BETWEEN

TERMINALS 4 AND 12

ON FLAME CONTROL

BOARD

yes

UNIT

MEMBRANE

INTACT?

FUME PRESSURESWITCH CONTACT

CLOSE

230V

BETWEEN

TERMINALS 4 AND 10

ON FLAME CONTROL

BOARD

CHECK AND/OR

REPLACE FUME

PRESSURE

SWITCH

230V BETWEEN

TERMINALS 5 AND 5

ON FLAME CONTROL

BOARD

yes

no

yes230V BETWEEN

BLUE/BLACK AND

BROWN WIRES

ON FAN

yes

yes

no

DOES PUMP

ROTATE AT 3RD

SPEED?

REPLACE

MEMBRANE

SHIFT SWITCH TO 3RD

SPEED OR REPLACE

PUMP IF IT SHOULDN’T

WORK

CHECK OR REPLACE

SHAFT (FOR EX.

LUBRICATE IT)

REPLACE

CONTROLBOARD




N U A L A 2

IGNITION

ELECTRODE

SPARK

IGNITION

BLOCK AFTER

IGNITION

END

MECHANICAL

OPENING OF

GAS VALVE

CONTROLS?

CHECK AND/OR

REPLACE

PRESSURE

SWITCH AND/OR

CONNECTIONS

REPLACE

PRESSURE

SWITCH

VENTURI AND

SILICONE PIPES ARE

CLEAN

SWITCHESPRESSURE SWITCH

CONTACT

REPLACE

FLAME

CONTROL

APPLIANCE

THERE ARE 230 VBETWEEN

TERMINALS 7 AND NON FLAME CONTROL

BOARD

yes

no

no

CHECK

AND/ORREPLACE

FLAME

CONTROL UNIT

IS IGNITION

ELECTRODE

TERMINAL POWERED?

ATTENTION:

10 kV PRESENT

CHECK AND/OR

CLEAN

no

no

yes

no

yes

yes

nono

yesyes

yes

yes

no

no

no

yes

noyes

A 3

THERE ARE230 V BETWEEN

TERMINALS 8 AND N ONFLAME CONTROL

BOARD

CHECK AND/OR

REPLACE

IGNITION

ELECTRODE

no

no

yes

yes

DEPRESSIONBETWEEN VENTURI AND

PITOT PIPE IS > 11 mmCOLUMN OF

WATER

CHECK FUME

EXHAUSTION

AND FAN

GAS

PRESSURE ON

INPUT EXCEED

13.7 BARS

WARN

USER

FLAME CONTROL

APPLIANCE OK?

REPLACE

FLAME

CONTROL

APPLIANCE

REPLACE GAS

VALVE



51

IS SLOW STARTING

PRESSURE LOW?

no

IS DETECTION

ELECTRODE TO BE

CHECKED?

REPLACE

DETECTION

ELECTRODE

yes

no IS DETECTION

ELECTRODE OK?

REVERSE

TERMINAL BOARD

POLARITY

INSTALL PHASE-TO-

PHASE KIT

IS POWER

POLARITY REVERSED?

RESET

BOILER

no

yes

no

yes

no

A 3

yes

yes

PHASE-TO-PHASE

POWER

LIMIT THERMOSTAT

ACTIVATED

REPLACE FLAME

CONTROL APPLIANCE

Note: check power polarity is correct byswitching tester to alternate current andchecking that 230V exist between line and

ground terminals, with 0 V voltagebetween neutral and ground terminals.

Install phase-to-phase kit if voltagebetween line and ground terminals andbetween neutral and ground terminals is

+/- 110 V.

INCREASE SLOW

STARTING

PRESSURE




N U A L

SELECT DHW MODEWITH MAXIMUM DHW

TEMPERATURE

yes

no

no

yes

no

TEST BBOILER OPERATION IN DHW MODE

OPEN

HOT WATER

COCK

BURNER

SWITCHES ON

CHECK

BOILER

BY TEST A

VOLTAGE

ON TERMINALS

1 AND 2 ON

FLAME CONTROL

BOARD

IS > 10 Vdc

VOLTAGE > 10Vdc

ON TERMINALS x 5.17

AND x 5.18 ON

CONTROL BOARD

REPLACE

CONTROL

BOARD

REPLACE

HARNESS AND

CONNECTIONS

yes

no

yesWAIT UNTIL VOLTAGE

ON TERMINALS 1

AND 2 OF FLAME

CONTROL BOARD

IS < 1.2 V

VOLTAGE

ON TERMINALS

1 AND 2 OF

FLAME CONTROL

BOARD IS < 1.2 V

yes

no

TAKE DHW

TO MINIMUM

TEMPERATURE

PRIMARY

TEMPERATURE

> 80°C

REPLACE NTC

SENSOR

no

yes

yes

REPLACE

CONTROL

BOARD

NTC SENSOR OK

no

no

yesyes

BURNER

AND FAN

SWITCH OFF

B1

WAIT UNTIL

PRIMARY TEM-

PERATURE

IS > 40°C

PRIMARY

TEMPERATURE

IS HIGHER THAN

40°C

REPLACE

CONTROLBOARD

BEGINNING



53

B1

TAKE DHW

TEMPERATURE TO

MAXIMUM

no

yes

yes

yes

yes

no

BURNER AND

FAN SWITCH ON WAIT UNTIL PRIMARY

TEMPERATURE IS < 80°C

PRIMARY

TEMPERATURE

IS > 80°C

REPLACE CONTROL

BOARD

CLOSE HOT

WATER COCK

BURNER, PUMP

AND FAN

SWITCH OFF

noEND

DHW

FLOW-SWITCH OK

CHECK AND/OR

REPLACE DHW

FLOW-SWITCH

REPLACE CONTROL

BOARD

no




N U A L TEST C

BOILER OPERATION IN CH MODE

BEGINNING

no

yes

yes

no

yesno

no

yes

BURNER

SWITCHES ON

SELECT CH MODE

WITH MAXIMUM CH

TEMPERATURE

CLOSE TERMINALS 1-3 ON THE

TERMINAL BOARD, BY ACTIVATING

ROOM THERMOSTAT OR

CONNECTING TERMINALS 1-3 TO

TERMINAL BOARD

VOLTAGE

ON TERMINALS

x 4.14 AND N ON

CONTROL

BOARDVOLTAGE ON

TERMINALS 1 AND 2

OF FLAME-CONTROL

BOARD IS > 6Vdc

VOLTAGE

ON TERMINALS

x 4.13 AND N ON

CONTROL

BOARD

CHECK

BOILER BY

TEST A

CHECK AND/ORREPLACE

HARNESS ANDCONNECTIONS,

AS WELL AS ROOMTHERMOSTAT OR

CONNECTIONBETWEEN TER-MINALS 1 AND 3

yes

VOLTAGE

> 6Vdc ONTERMINALS x 5.17

AND x 5.18 ONCONTROL

BOARD

CHECK AND/OR

REPLACE

HARNESS AND

CONNECTIONS

REPLACE

CONTROL

BOARD

WAIT UNTIL VOLTAGE

ON TERMINALS 1 AND 2

ON FLAME CONTROL

BOARD IS < 1.2 V

VOLTAGE

ON MODULATOR

COIL IS < 1.2 V

TAKE CH

TEMPERATURE

TO MINIMUM

noyes

REPLACE

CONTROL

BOARD

BURNER AND

FAN ARE OFF

TAKE CH

TEMPERATURE

TO MAXIMUM

C1

no

no

no

yes

yes

PRIMARY

TEMPERATURE

IS > 80°C

WAIT UNTIL

PRIMARY

TEMPERATURE

IS > 80°C

REPLACE NTC

SENSOR

NTC SENSOR OK

REPLACE

CONTROL

BOARD

no

yes



55

BURNER

AND FAN SWITCH ONyes

C1

yes

no

no

WAIT FOR 3

MINUTES

BURNER AND

FAN SWITCH ON

VON/VOFF

JUMPER ACTIVATED

no

REPLACE CONTROL

BOARD

REPEAT TEST

FROM THE

BEGINNING

REMOVE

JUMPER

OPEN TERMINALS 1-3

ON TERMINAL BOARD OR

ROOM THERMOSTAT

no

no

yes

END

TERMINALS 1-3

ARE ON AND ROOM

THERMOSTAT

OPERATES

OPEN TERMINALS 1-3

OR CHECK ROOM

THERMOSTAT

BURNER AND

PUMP SWITCH OFF

REPLACE

CONTROL

BOARD

yes

yes



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