Arca Caldaie ASPIRO A 29 R/SA Owner's manual

ASPIRO
Installation
Operation
Maintenance
www.arcacaldaie.com

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The company ARCA s.r.l. will not be liable for any mistake or inaccuracy of translation and printing. In
the future, company ARCA reserves the right to apply modifications to its range of products should they
be useful or necessary.
The present documentation is also available as PDF files. Please fell free to contact our technical
department to get the files.
code: MAN1004
pages: 38
issue: 4th edition
revision: 2007, june

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INDEX
1. GENERAL PRESCRIPTIONS ........................................................................................................................6
2. TECHNICAL CHARACTERISTICS AND OVERALL DIMENSIONS ...............................................................7
3. GASIFICATION TECHNOLOGY ....................................................................................................................8
4. MAIN BOILER COMPONENTS......................................................................................................................8
4.1. WOOD CHARGING CHAMBER .................................................................................................................................8
4.2. MAIN BURNER REFRACTORY CEMENT FRAME AND BARS................................................................................. 8
4.3. HEAT EXCHANGE AREA AND CATALYST ELEMENTS ..........................................................................................8
4.4. SMOKE DRAFTING PASS-THROUGH CHAMBER AND FAN...................................................................................9
4.5. COMBUSTION AIR DISTRIBUTION ASSEMBLY ......................................................................................................9
4.6. HOT SANITARY WATER HEAT EXCHANGER .........................................................................................................9
4.7. EMERGENCY HEAT EXCHANGER...........................................................................................................................9
4.8. TEMPERATURE PROBES RECEPTACLES..............................................................................................................9
4.9. BYPASS PUMP ..........................................................................................................................................................9
4.10. INSULATION ..............................................................................................................................................................9
5. INSTALLATION............................................................................................................................................10
5.1. INSTALLATION IN A BOILER ROOM ......................................................................................................................10
5.2. EXTERNAL HOUSING MOUNTING......................................................................................................................... 10
5.3. SYSTEM EXPANSION TANK...................................................................................................................................11
5.4. FLUE DUCT..............................................................................................................................................................11
5.5. EMERGENCY HEATSINK RELIEF VALVE CONNECTION .....................................................................................12
6. ELECTRONIC PANEL, RELEASE 2007 ......................................................................................................13
6.1. GENERAL CHARACTERISTICS ..............................................................................................................................13
6.1.1. DEFAULT ENDOWMENT .................................................................................................................................13
6.1.2. OPTIONAL ENDOWMENT................................................................................................................................13
6.2. DISPLAY...................................................................................................................................................................13
6.3. OPERATION ENVIRONMENTS ...............................................................................................................................13
6.4. SCHEMATIC DIAGRAM AND ELECTRONIC BOARD WIRING...............................................................................14
6.5. TEMPERATURE PROBES ELECTRICAL CONNECTIONS..................................................................................... 15
6.6. BRACKET HARNESS WIRING ................................................................................................................................15
7. TEMPERATURE DISPLAYING, PARAMETERS CHANGING OR SETTING...............................................16
7.1. PROBES ENABLING AND DISABLING (FUNCTION PARAMETER #1) .................................................................16
7.2. BOILER AND ACCESORIES FUNCTIONAL SETTINGS (FUNCTION PARAMETER #2) .......................................17
7.3. DISPLAY LANGUAGE SELECTION.........................................................................................................................17
8. HEATING ONLY OPERATION.....................................................................................................................17
8.1. BOILER PARAMETERS SETTING “HEATING ONLY OPERATION”.......................................................................18
8.2. PARAMETERS DEFINITION “HEATING ONLY OPERATION” ................................................................................18
8.3. HYDRAULIC CONNECTIONS..................................................................................................................................19
8.3.1. GENERAL CONNECTION DIAGRAM FOR HEATING ONLY OPERATION WITH OPEN EXPANSION
TANK .................................................................................................................................................................19
8.3.2. GENERAL CONNECTION DIAGRAM FOR HEATING ONLY OPERATION WITH MIXING VALVE................. 20
8.3.3. GENERAL CONNECTION DIAGRAM FOR HEATING ONLY OPERATION WITH OPEN EXPANSION
TANK/CLOSED EXPANSION TANK .................................................................................................................20
9. HEATING AND HOT WATER PRODUCTION WITH INTERNAL HEAT EXCHANGER ...............................21
9.1. BOILER PARAMETERS SETTING “HEATING AND HOT WATER PRODUCTION BY MEAN OF AN
EXTERNAL TANK”..................................................................................................................................................22
9.2. PARAMETERS SETTING “HEATING AND HOT WATER PRODUCTION BY MEAN OF AN EXTERNAL TANK”... 22
9.3. HIDRAULIC CONNECTIONS ...................................................................................................................................23
9.3.1. GENERAL CONNECTION DIAGRAM FOR A BOILER WITH EXTERNAL HOT WATER PRODUCTION
TANK AND SOLAR PANELS ............................................................................................................................24
9.3.2. GENERAL CONNECTION DIAGRAM FOR A BOILER WITH SOLAR PANELS AND CLOSED EXPANSION
TANK .................................................................................................................................................................24
10. BOILER OPERATION WITH PUFFER OR PUFFER COMBI .......................................................................25
10.1. PARAMETERS SETTING “OPERATION WITH PUFFER OR PUFFER COMBI”..................................................... 26
10.2. PARAMETERS DEFINITION “OPERATION WITH PUFFER OR PUFFER COMBI” ................................................26
10.3. HIDRAULIC CONNECTION DIAGRAMS..................................................................................................................27
10.3.1. GENERAL CONNECTION DIAGRAM WITH PUFFER OR BOILER COMBI AND SOLAR PANELS................ 28
10.3.2. GENERAL CONNECTION DIAGRAM WITH HEAT EXCHANGER, PUFFER OR BOILER COMBI AND
SOLAR PANELS ...............................................................................................................................................28

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11. “N” ZONES SYSTEMS CONNECTIONS......................................................................................................29
12. FIRING AND STOPPING .............................................................................................................................29
12.1. FIRING......................................................................................................................................................................29
12.2. FIRING CYCLE STARTING......................................................................................................................................30
12.3. FUEL CHARGING ....................................................................................................................................................30
12.4. COMBUSTION AIR ADJUSTING .............................................................................................................................30
12.5. WARNINGS ..............................................................................................................................................................31
13. MAINTENANCE AND CLEANING................................................................................................................31
13.1. DAILY CLEANING ....................................................................................................................................................31
13.2. WEEKLY CLEANING................................................................................................................................................31
13.3. MONTHLY CLEANING .............................................................................................................................................32
13.4. SPECIAL MAINTENANCE........................................................................................................................................32
13.5. MATERIALE DI CONSUMO .....................................................................................................................................32
14. TROUBLESHOOTING .................................................................................................................................34
14.1. CONTROL PANEL TROUBLESHOOTING TERMODUE .........................................................................................34
14.2. BOILER TROUBLESHOOTING................................................................................................................................35
15. OPERATION ANORMALITIES.....................................................................................................................36
15.1. ACUSTIC WARNING................................................................................................................................................36
16. GENERAL TECHNICAL TIPS .....................................................................................................................36
16.1. SETTINGS AND HIGHEST PERMITTED TEMPERATURES...................................................................................36
16.2. FIRST FIRING ..........................................................................................................................................................37
16.3. REFRACTORY CEMENT EXISTING IN THE BOILER.............................................................................................37
16.4. BOILER AUTONOMY AND FUEL CHARGING INTERVALS ...................................................................................37
16.5. EXPLOSIONS...........................................................................................................................................................37
17. MODEL CHOOSING ...................................................................................................................................37
17.1. BOILER POWER ......................................................................................................................................................37

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1. GENERAL WARNINGS
The instruction manual is an integral part of the product and is shipped along with it to the customer.
Carefully read any warning reported in this manual because they provide important informations concerning
safe operation, correct installation and use. Carefully store in a safe place this manual for any future needing.
The installation must be carried out only by qualified personnel or by an authorized ARCA technical center
following the producer’s recommendations and guidelines. A wrong installation may cause harm to people,
animals and objects being ARCA not liable for them.
Control for product integrity In case of doubt don’t use the product and address to your vendor. The packing
components must not be thrown away in the surrounding environment or left to the reach of children.
Before performing any changing or maintenance or cleaning operation on the system, turn off the boiler using
the main external switch.
In case of boiler fault, turn it off without performing any attempt to repair it by yourself. Address only to
qualified personnel. Any repair must be performed by an authorized technical center only, using only original
spare parts.
We take no responsibility for any damage which could result from wrong installation or use or from being not
respected the instructions and recommendations given in this manual.
Not respecting the instructions and guidelines of this manual may compromit the security level of the whole
system or of its components, causing danger for the customer, for which we take no responsibility.
WARNING !
The first firing and the final test of the boiler must be performed by an authorized
technical center only.

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2. TECHNICAL CHARACTERISTICS AND OVERALL DIMENSIONS
Key:
1 Primary air stream adjusting A1 Heating circuit delivery
2 Secondary air stream adjusting A2 Heating circuit return
3 Flame control bull's eye A3 Boiler water descharging
4 Bottom door (combustion chamber) A4 Sanitary hot water heat exchanger connections
(only SA version)
5 Upper door (wood chamber) A5 Security heat exchanger connections
6 Combustion air modulator A6 Temperature probes receptacles (S4)
7 Anti deflagration door A7 Temperature probe receptacle (S5)
8 Fan motor A8 Smoke outlet
9 Smoke chamber inspection door
Model
Minimum
rated
power
kcal/h
kW
Max.
rated
power
kcal/h
kW
Max.
power
to the
burner
kcal/h
kW
Boiler
weight
kg
Boiler
Water
content
liters
Insertion
losses
water side
m water
column
Insertion
losses
smoke side
Mm water
column
Max
rated
pressure
bar
Comb.
chamber
volume
liters
Wood
chamber
opening
size
mm
Maximum
wood
logs
length
cm
A 29 R/SA
14,000
16
26,000
30
29,500
34 380 95 0.10: 0,3 4 95
290 ×330 53
A 34 R/SA 20,000
23
25,000
29
29,600
34.5 470 115 0.08 0,4 4 135
340 ×430 53
A 43 R/SA
23,000
27
35,000
41
43,000
50 470 115 0,08 0,4 4 135
340 ×430 53
A 52 R/SA
28,000
33
42,000
49
52,000
60 555 135 0.10: 0,6 4 185
340 ×430 68
A 70 R/SA
38.000
44
59000
69
70.000
81 685 170 0,05 0,3 4 230 340X520 74
A 90 R/SA
52000
60
72000
84
90.000
105 920 215 0,10 0,5 4 320 340X520 105
Model
A
mm
B
mm
C
mm
D
mm
E
mm
F
mm
G
mm
H
mm
A1 A2
ø
A3
ø
A4
ø
A5
ø
A6 A7
ø
A8
ø
A 29 R/SA 550 850 1,200 190 150 980 80 1130 1”¼ ½” ½” ½” ½” 180
A 34 R/SA 650 850 1,300 190 150 1,080 80 1220 1”½ ½” ½” ½” ½” 180
A 43 R/SA 650 850 1.300 190 150 1.080 80 1220 1”½ ½” ½” ½” ½” 180
A 52 R/SA 650 1.030. 1,300 190 150 1,080 80 1220 1”½ ½” ½” ½” ½” 180
A 70 R/SA 760 1.120 1.425 190 150 1,070 100 1340 2” ½” ½” ½” ¾” 220
A90 R/SA 760 1.370 1.425 190 150 1,070 100 1340 2” ½” ½” ½” ¾” 220

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3. GASIFICATION TECHNOLOGY
Boiler ASPIRO operation is based upon the gasification technology applied to wood. The solid fuel, stored in
the upper collection chamber in contact with hot ashes in its bottom part, on the burner’s grate, releases
combustible gazes which may be fired when mixed with the main air stream. This flammable compound is
sucked through the slot existing in the bottom part of the wood collection chamber, where it will light
producing the characteristic
“reverse flame”.
The gasification principle, not allowing wood to burn directly as in any other classic arrangement but using
instead the gazes released under high temperature conditions, allows a complete burning of the fuel which
permits to get high thermal yield and a very low level of harmful emissions in the smoke released outside.
The boiler ASPIRO has been designed to limit to the maximum possible level the harmful action of the acid
condensate. The burner chamber has a 8 mm thickness walls and has no welding in its upper part;
furthermore, the rear and front walls are protected by a refractory cement layer and they are not in touch with
water (dry walls).
4. MAIN BOILER COMPONENTS
4.1. WOOD COLLECTION CHAMBER
It is the
fuel "tank" of the boiler. In this chamber, located in the boiler upper part, the wood logs are charged
after being succesfully performed the ignition procedure, getting a first layer of hot ashes.
4.2. MAIN BURNER REFRACTORY CEMENT FRAME AND BARS
In the middle part of the boiler, between the fuel chamber and the bottom part where the heat exchange
takes place, is located the burner, built with a special designed refractory cement frame with a slot in its
central part and a grate. The grate is formed by single elements (the “bars”), realized in chrome cast iron,
which support the ashes while letting the released gazes passing through downward.
4.3. HEAT EXCHANGE AREA AND CATALYST ELEMENTS
The gazes released by wood, after being passed through the cast iron bars, light producing a bluish vertical
reverse flame which touches a special shaped chrome cast iron cylinder called "the catalyst".
The flame, passing through this cast iron element which reaches a very high temperature, will have
completely burnt the main part of its residual carbon particles which were not burnt before. The combustion
gazes, flowing through the heat exchanging zone, warm up the water.
Key:
1 Primary air stream adjusting
2 Secondary air stream adjusting
3 Flame control bull's eye
4 Bottom door (combustion
chamber)
5 Upper door (wood chamber)
6 Combustion air modulator
7 Anti deflagration door
8 Fan motor
9 Hot sanitary water heat
exchanger (SA versions only)

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4.4. SMOKE DRAFTING PASS-THROUGH CHAMBER AND FAN
The gazes resulting from the combustion process, after being released their heat charge to the water, are
collected in the smoke pass-through chamber located in the rear part of the boiler. In the smoke chamber has
place the drafting fan with horizontal axle arrangement, realized with an electric motor and the impeller. The
fan is easy to be maintained being fixed with wing nuts.
4.5. AIR DISTRIBUTION ASSEMBLY
In the front part of the boiler, in the middle between the upper and the bottom door, is located the combustion
air suction port. The immission duct has an internal gravitational closing door which closes the air passage
when the drafting fan stops, and another temperature commanded external closing.
The air entering in the air chamber is then divided in primary and secondary air stream. The main air stream
enters the wood collecting chamber and creates the combustible mixture which is fired after passing through
the cast iron grate. The secondary air stream flows through some internal ducts realized in the refractory
cement layer thickness encountering the wood gazes in the burner central slot, where starts the flame,
optimizing the combustion process.
4.6. HOT SANITARY WATER HEAT EXCHANGER
The ASPIRO boiler may be equipped with an internal real time heat exchanger for hot sanitary water
production purposes (SA models only). The heat exchanger is realized with a copper pipe coil plunged in the
heating circuit water gap, around the boiler main body, with the hidraulic connections in the rear part of the
boiler.
4.7. EMERGENCY HEAT EXCHANGER
The boiler is equipped with a security heat exchanger. Its function is to let the boiler cooling down in the
evenience of reaching excessive temperature by the mean of a heat relief valve connected to the security
exchanger (refer to paragraph 5.5). This is realized by a steel pipe coil with its hidraulic connections in the
rear part of the boiler (connections “A5”). The temperature sensor of the heat relief valve is to be positioned
on the A6 connection.
4.8. PROBES RECEPTACLES
In the rear part of the boiler are two holes (A6) both with a ½” pipe coupling having the following function:
 to fit the copper receptacle for installing the thermostatic sensors used by the electronic control board;
 to fit another copper receptacle for other temperature sensing device.
4.9. BYPASS PUMP
With the aim to reduce any condensation in the boiler it is mandatory to install a bypass pump . The bypass
pump must be connected between the delivery connection (A1) and the return connection (A2) with water
flux direction upward. Our company may deliver the whole bypass kit, complete with bypass pump, pipes and
fittings.
4.10. INSULATION
Insulation of ASPIRO boiler is obtained using a 60 mm thickness mineral fiber layer in touch with the boiler
body which is covered by the external boiler housing, realized by sheet metal panels painted with epoxy
powder paint.

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5. INSTALLATION
The ASPIRO boiler does not feature any difference from an ordinary solid fuel boiler; therefore, no other
installation prescriptions than what stated by the regulations in force is applicable. The installation room has
to be equipped with venting openings having a total surface not less than 0,5 m2. In order to make simpler
smoke passages cleaning, a free space not less than boiler depth must be leaved in front of it and the boiler
door must be free to open at least 90°.
The boiler can be put directly in touch with the floor, because is equipped with a self-bearing chassis.
Anyway, if the floor is very wet, it is better to build a concrete platform where to position the boiler on. After
positioning, the boiler must be in horizontal and stable position in order to reduce vibrations and noise.
5.1. INSTALLATION IN A BOILER ROOM
The ASPIRO boilers must be installed only in rooms having the characteristics stated by the rules and
regulations in force regarding boilers installation rooms (please contact the fire department to get more
details).
The distances for the correct positioning of the boiler in the installation room are as follows:
5.2. EXTERNAL HOUSING MOUNTING
 Install the boiler 1in its installation room and complete the hidraulic connections.
 Put the mineral fibre insulation layer all around the boiler body 2fixing it with the metal bands 3.
 Fix the antideflagration doors at the base of the smoke chamber tightening the screws 4.
 Install the fan 5in place in the smoke chamber fixing it with the wing nuts.
 Position in place the side parts 6and 7, being careful to correctly insert their upper bends in the slots
on the upper part of the front and rear boiler body plates, while inserting the lower bends in the
internal side of the L shaped base frame.
 Put the upper part of the housing 8over the side parts 6and 7, carefully inserting the studs on the
side parts in the holes on the cover, then gently press down to have the studs retained by the cover
holes springs
 Fix the electronic control panel 9to the housing cover 8straightening the thermostats capillary tubes
and letting them pass under the external housing to the rear part of the boiler where they will have
their bulbs fitted in the receptacles on the back of the boiler.
 Fit the back panel 10, fixing it to the side parts studs 6and 7with the back panel retaining springs.
 Fit to the wood collecting chamber the protection panel 11, with its handle M fixed.
 Fix the hood 13 on the middle door using the bayonet joints.
 Fix the protection panel 12 to the bottom door with its knob Pmounted.

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5.3. EXPANSION TANK
According to the regulations in force in Italy, any heating appliance with solid fuels must be equipped with
open expansion tanks.
5.4. FLUE DUCT
The flue duct is very important for the proper operation of the boiler; it must be seal and thermal insulated.
Old or new flue ducts, built without respecting the above prescriptions, can be reused introducing a metal
duct in the interior. Another metal duct must be introduced in the interior of the existing flue duct filling the
gap between the external surface of the inner duct and the internal surfaces of the old duct with insulating
materials. Flue ducts realized with cement blocks must have any joint perfectly sealed to avoid the
condensate sticking to the inner surfaces staining the external wall.
The construction of new flue ducts requires setting up a project satisfying any prescription required by the
regulations in force.
In any case the flue duct must feature a good draft, at least 2 mm of water column depression at the base of
the duct when cold. Lower draft values will cause the boiler cutting off completely during the stand by periods
and tar and condensate will stick in the air inlet passages. On the other hand, too high draft values will cause
high thermal inertia and poor fuel economy.
We recommend anyway the use of a draft adjusting device to keep a constant depression value in the duct,
to avoid unwanted power raising.

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5.5. THERMAL RELIEF VALVE CONNECTION
Key:
A3 Boiler water descharging
A5 EMERGENCY HEAT EXCHANGER
A6 Probes receptacles S4
A7 Probe receptacles S5
 Connect the heatsink relief valve to one of the two A5 connections.
 Connect cold water supply to the heatsink relief valve.
 Connect the free A5 fitting (hot water waste) to an exhaust duct.
 Insert the heat relief valve temperature sensing bulb in the free A6 receptacle.
Note: the heatsink relief valve could be installed even on the waste hot water outlet, but this wouldn't add
anything from the point of view of the overall operation security level of the boiler, and debris in the heat
exchanger could plug or stick the relief valve.

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6. ELECTRONIC PANEL, RELEASE 2007
The electronic panel equipped with the TERMODUE control board is designed to control all the wood fueled
ARCA boilers.
1
2
45 6
12
13
10
11
8
9
7
3
Key:
1 Main switch (with green telltale) 8 Controls and functions keyboard
2 Security thermostat 9 “E” button for parameters and temperature settings
3 Reset button 10: Automatic/Manual operation button
4 Green indicator; solar panels 11 Turn on/turn off boiler functions button
5 Yellow indicator: sanitary hot water production
tank pump
12 Yellow indicator: bypass pump
6 Red indicator: system pump 13 Red indicator: fan
7 Control panel display ACUSTIC WARNING: EXCESSIVE BOILER TEMPERATURE
6.1. GENERAL CHARACTERISTICS
 Microprocessor controlled, equipped with EEPROM memory (in case of blackout, all settings return to
the state they were before).
 Non volatile memory (the stored data will be retained for about 10 years without power).
 4 rows liquid crystal display.
 Self diagnostic program to detect internal errors or wrong probes connections.
6.1.1. DEFAULT ENDOWMENT
 The electronic control board TERMODUE is equipped with a preprogrammed microprocessor for the
whole range of wood fueled ARCA boilers.
 Basic endowment with 3 PTC insulated temperature probes.
 230/12 V AC transformer (code TRA0002).
 Mechanical security thermostat with manual reset.
6.1.2. OPTIONAL ENDOWMENT
 Expansion board for multiple zones systems (SCH0005C), see paragraph 11 (page 30).
6.2. DISPLAY
6.3. OPERATION MODES
The electronic board is designed to manage three different operation modes. Operation modes “HEATING
ONLY”, “HEATING AND HOT SANITARY WATER PRODUCTION WITH SINGLE OR DOUBLE COIL HEAT
EXCHANGER ARRANGEMENT”, “HEATING AND PUFFER TANK MANAGEMENT”. The parameters
settings are specific to each operation mode of the boiler. PUFFER is a term which describes a heat
accumulating device, as a relatively large tank.
(
In the picture are shown the main boiler
functions which can be displayed).
When the red button on the control panel is
pressed (
)
the boiler is turned ON and
the drafting fan starts.

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6.4. SCHEMATIC DIAGRAM AND ELECTRONIC BOARD WIRING
Key:
IMain switch S1 Solar panels temperature probe
SGreen telltale S2 Puffer low temperature probe
TRA 220/12 V AC transformer S3 Puffer high temperature probe
TA Room thermostat S4 Heating system delivery temperature probe
FFuse S5 Heating system return temperature probe
MP Door microswitch PR Bypass pump
PPS Solar panels pump V Fan
PB Puffer tank pump TS Security thermostat
PI System pump

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6.5. PROBES CONNECTION
NOTE: to avoid erratic temperature displaying, if the probe connection cable is near to other power cables or
longer than 3 mt, it is necessary to use shielded cable. The following drawings show how the hot terminal of
each probe must be connected to the odd board terminal while the shield must be connected to the even
board terminal. By this way a shielded connection is got, getting rid of any electrical noise.
6.6. BRACKET HARNESS WIRING
NOTE:
Terminals 21 and 22 are bridged to allow system pump operation if a room thermostat is not employed.
WARNING:
When a room thermostat is used, remove the wire bridge and control for a right connection to the room
thermostat. If the system pump does not work, control for a faulty room thermostat.

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7. TEMPERATURE DISPLAYING AND PARAMETERS CHANGING OR
SETTING
Displaying procedure:
Step 1: You can browse the various options using the arrow buttons and on the panel.
Setting procedure:
Step 1: To enter the functional parameters setting procedure press and hold the button for about
15'' until PROG> is displayed.
Step 2: When the next screen appears, the first parameter with its actual value will be shown.
Step 3: You can move through the various options using the arrow buttons and on the panel.
Step 4: With the parameter whose value is intended to be changed displayed, use the arrow button
to change the value; the parameter starts blinking. Using the buttons and the
parameter value is changed. As soon as the parameter will reach the requested value, it can
be stored pressing the arrow.
Step 5: To have other parameters changed you can browse them using the directional arrows
and on the panel.
Step 6: After being finished with parameters setting or modifying, in order to have them transferred
on the board non volatile memory press button for about 10-15''.
7.1. PROBES ENABLING AND DISABLING (FUNCTION PARAMETER #1)
To have each probe ON or OFF the parameter “Function parameter #1” must have a numeric value which is
the result of the weighted sum of all the probes:
S1 (solar panels circuit delivery temperature) 1
S2 (heat exchanger low temperature) 2
S3 (heat exchanger temperature) 4
S4 (system delivery temperature) 8
S5 (system return temperature) 16
The number is obtained by adding the weights of the required probes for the operation mode choosen by the
next parameter “Function parameter #2”.
Function parameter #1 setting example
For example, if the boiler is intended to work in heating only mode, refer to schematic diagrams 8.3.1, 8.3.2,
8.3.3., must be present the two probes S4 and S5. Therefore the values 8 and 16 are added = 24. Setting the
value 24 the two required probes are abled.
Note:
In the evenience of problems during a probe installation, better you will have the two terminals on the board
for that probe wire bridged to avoid the warning message of missing or faulty probe being displayed.

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7.2. BOILER AND ACCESORIES SETTINGS (FUNCTION PARAMETER #2)
This parameter sets the electronic board for each of the three different operation modes (“HEATING ONLY”,
“HEATING AND HOT SANITARY WATER PRODUCTION WITH SINGLE OR DOUBLE COIL HEAT
EXCHANGE ARRANGEMENT”, “HEATING AND PUFFER TANK MANAGEMENT”). The functional settings
follow the same logic of the “Function parameter #1”. To calculate the required value you will add the
weighted values assigned to each function in the following way:
Functional settings:
Without SOLAR PANELS set “0
With SOLAR PANELS set “1”
With BYPASS PUMP set “0”
Without BYPASS PUMP set “2”
Without external hot sanitary water tank set “0”
With external hot sanitary water tank set “4”
External tank, type with heat exchanger coil set “0”
External tank, type PUFFER or PUFFER COMBO set “8”
WARNING:
to set a Puffer or Puffer combo type tank add 8, but must also be added the value 4 for the external tank
setting up. In this example, you will have to introduce the value 12.
Function parameter #2 setting example
If setting up an external coil type hot water production tank is required, along with solar panels and
the bypass feature, the following calculation will be performed:
Parameter value Function 2 = 1 (with solar panels) + 0(bypass feature present) + 4 (external hot water tank)
+ 0(coil type tank) Total = 5.
7.3. DISPLAY LANGUAGE SELECTION.
Parameter #12 selects the display language.
4 languages are available:
Value 00: italian
Value 02 : romanian
Value 04 : french
Value 06 : spanish
8. “HEATING ONLY” OPERATION
To connect the boiler in heating only mode refer to connection diagrams 8.3.1 - 8.3.2 - 8.3.3. controls the
system pump and the bypass pump The required probes are S4 (system delivery high point probe) and S5
(system return low point probe). These settings are valid even for models SA with real time hot sanitary water
production heat exchanger.
To have the boiler turned ON and to start the "timed operation cycle" must be pressed the red button on the
control panel ( ); the drafting fan is started and the display changes from OFF (standby) to ON. The fan
remains ON until the water temperature reaches the value set by the parameter “Boiler working temperature”.
NOTE: it is important to remember that any time the button ( ) is pressed, the timing options and the
options related to the operation mode AUT (Automatic) or MAN (Manual) are stored on a non volatile
memory. In the case of black-out, the boiler will start from the point where it was at that moment.
The system pump is controlled by the room thermostat, but only if the boiler water temperature is more than
the value set by the parameter “Minimum boiler temperature” and “Temperature difference in heating mode”.
If the boiler does not reach the temperature required during its ON timed cycle, will pass to the standby
mode.
The bypass function avoid water temperature stratification between its highest and lowest points. The
parameter “Maximum boiler body temperature differential” turns ON the bypass pump if the temperature
difference between the high and the low point of the boiler is more than the preset value. The bypass circuit
is always ON both in standby and in “Timed operation cycle” at any temperature.

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8.1 BOILER PARAMETERS SETTING “HEATING ONLY MODE”
FUNCTIONAL PARAMETERS
Modifying these parameters or wrong values may cause boiler malfunctions and in consequence problems
on the whole system. We recommend to have the boiler fired for the first time only by technical skilled
personnel or by an authorized service center.
8.2. PARAMETERS SETTINGS “HEATING ONLY OPERATION”
0. Working boiler temperature: it means the temperature at which the boiler will enter the standby
mode. When the set temperature is reached, the electronic control turns OFF the fan. The fan will be
started again when the water temperature falls under the “temperature difference in heating mode”
(usually 2 °C) plus another hysteresis degree.
Example: “Working boiler temperature”= 80°C - (2+1)= 77°C; therefore, when the system pump or
the hot water tank pump are stopped, if the boiler temperature falls down under 77 °C and the
temperature of 80 °C won't be reached within the time set in the parameter “Standby delay time”, the
boiler will enter back the standby mode.
1. Minimum boiler temperature: The minimum boiler temperature is that value under which the pumps
are stopped to avoid condensation issues. In the same time, if the boiler remains under this
temperature for the time “Standby delay time”, the boiler gets back in standby mode.
2. Maximum allowed temperature in thermal inertial mode: The maximum temperature allowed for the
boiler; if the temperature is more than this, the boiler will stop producing an ALARM sound. In this
case the electronic control board starts the system pump and the bypass pump to dissipate the
exceeding heat. If the temperature reaches 104 °C the manual reset security thermostat opens the
supply circuit to the fan stopping it until it won’t be rearmed.
NOTE: if the boiler temperature reaches frequently its maximum allowed value, check for a good
closing of the round air port door (not more than 2 mm air passage) when the boiler reaches its
working temperature, or for poor doors seal or for damaged doors gaskets.
3. Minimum hot water tank temperature: not used in this operation mode.
4. Maximum hot water tank temperature: not used in this operation mode.
5. Temperature differential in heating mode: Sets the system pump on/off hysteresis. If the minimum
boiler temperature is 60 °C and the differential is set to 2 °C, when the room thermostat calls for heat
(contacts 21-22 closed), the system pump starts at 62°C and stops at 61°C (hysteresis on all
parameters). Furthermore, the same parameter sets the drafting fan on/off temperature differential
(see parameter “Working boiler temperature”).
6. Hot water preparing temperature differential: not used in this operation mode.
7. Solar panels heating temperature differential: not used in this operation mode.
Parameter description Recommended values
0 Boiler operating temperature 80°C
1 Boiler minimum temperature 65°C
2 Maximum boiler temperature in thermal inertial
phase
88°C
3 Minimum hot water tank temperature 45°C
4 Maximum hot water tank temperature 65°C
5 Temperature differential in heating mode 2.0°C
6 Temperature differential in hot water preparing mode 3.0°C
7 Temperature difference in solar panel heating mode 5.0°C
8 Maximum boiler body temperature difference 4.0°C
9 Boiler standby delay 50 min.
10: Function parameter #1:
Probes activation and deactivation. 24 (heating only )
11 Function parameter #2:
Boiler and accessories setting. 0 (heating only )
12 Language selection 00 (italian)

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8. Boiler body maximum temperature differential: If the system delivery temperature is more than that of
return by a difference more than the value set by this parameter, the bypass pump will be started to
balance the temperature difference between the boiler highest and lowest point.
9. Standby delay time: Sets the "timed operation cycle" when the boiler is operative. The cycle
activation is performed pressing the button ( ); the drafting fan starts. If the boiler temperature
falls down under the value “Minimum boiler temperature” (usually 60 °C), the boiler has the time set
by this parameter (usually 50’) to rise its temperature back above the said value, otherwise it will
enter the standby mode.
10. Function parameter #1 (probes activation/deactivation): See probes activation procedure description
(page16).
11. Function parameter #2 (optional setting): See optional settings description (page17).
12. Display language selection: See display language selection description (page17).
8.3. HYDRAULIC SCHEMATIC DIAGRAMS
All the schematic diagrams in this manual are given as reference only, and they must be validated by
authorized engineers. The company ARCA s.r.l. takes no responsibility for any harm to objects, persons and
animals caused by a wrong system project. For any other schematic diagram you may need, feel free to
contact ARCA technical department. Putting in service heating systems realized differently from what
recommended in this manual, or otherwise not authorized, will cause void of warranty.
Note:
The correct operation of the boiler requires the bypass pump to avoid harmful water temperature
stratifications.
The absence of the bypass pump will void the warranty.
8.3.1. GENERAL CONNECTION DIAGRAM FOR HEATING ONLY OPERATION WITH
OPEN EXPANSION TANK
S4
S5
PR
IR
PI
V
V
Key:
PI System pump V Non return valve
PR Bypass pump S4 Heating system delivery temperature probe
IR Heating system S5 Heating system return temperature probe

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8.3.2. GENERAL CONNECTION DIAGRAM FOR HEATING ONLY OPERATION WITH
MIXING VALVE
S4
S5
PR
VM
IR
PI
V
V
Key:
PI System pump VM Mixing valve
PR Bypass pump S4 Heating system delivery temperature probe
IR Heating system S5 Heating system return temperature probe
V Non return valve
8.3.3. GENERAL CONNECTION DIAGRAM FOR HEATING ONLY OPERATION WITH
OPEN EXPANSION TANK/CLOSED EXPANSION TANK
Key:
PI System pump V Non return valve
PR Bypass pump S4 Heating system delivery temperature probe
IR Heating system S5 Heating system return temperature probe
SP Plate heat exchanger