Arca Caldaie Aspiro 25 CTCA Quick start guide

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WOOD BOILER
ASPIRO
CTCA
SY 400 LCD 2022
I
In ns st ta al ll la at ti io on n
U
Us se e
M
Ma ai in nt te en na an nc ce e
www.arcacaldaie.com

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ARCA S.r.l. declines any responsibility for any inaccuracies that may be contained herein, if due to transcription or
printing errors. It also reserves the right to perform modifications on its products as deemed necessary or useful,
without affecting their basic features.
This documentation is also available in PDF format. Contact ARCA S.r.l. technical department for this request.
code: MAN1004SY400CTCA
pages: 59
edition: 2nd EDITION
revision: April 2022

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CO ON NT TE EN NT TS S
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1. . G GE EN NE ER RA AL L W WA AR RN NI IN NG GS S . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 6 6
1.1. PACKAGING AND TRANSPORT ................................................................................................................................................... 7
1.2. WARRANTY CONDITIONS ........................................................................................................................................................... 7
1.3. WARRANTY LIMITATIONS .......................................................................................................................................................... 7
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2. . T TE EC CH HN NI IC CA AL L S SP PE EC CI IF FI IC CA AT TI IO ON NS S A AN ND D S SI IZ ZE ES S . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 8 8
2.1. TECHNICAL FEATURES AND DIMENSIONS A25CTCA, A35CTCA, A50CTCA ................................................................................. 8
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3. . M MA AI IN N P PA AR RT TS S O OF F T TH HE E B BO OI IL LE ER R . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 9 9
3.1. WOOD STORAGE CHAMBER ....................................................................................................................................................... 9
3.2. MAIN STONE AND BARS ............................................................................................................................................................. 9
3.3. EXCHANGE ZONE AND CATALYST ............................................................................................................................................... 9
3.4. SMOKEBOX AND FAN ............................................................................................................................................................... 10
3.5. AIR DISTRIBUTION UNIT ........................................................................................................................................................... 10
3.6. DHW EXCHANGER .................................................................................................................................................................... 10
3.7. SAFETY HEAT EXCHANGER ....................................................................................................................................................... 10
3.8. WATER TEMPERATURE PROBE THERMOWELLS ....................................................................................................................... 10
3.9. RECIRCULATING PUMP (ANTI-CONDENSATION) ...................................................................................................................... 11
3.10. INSULATION ............................................................................................................................................................................. 11
3.11. SUPPLY WATER ........................................................................................................................................................................ 11
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4. . T TY YP PE E O OF F O OP PE ER RA AT TI IO ON N . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 1 11 1
4.1. GASIFICATION TECHNOLOGY .................................................................................................................................................. 11
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5. . I IN NS ST TA AL LL LA AT TI IO ON N . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 1 12 2
5.1. POSITIONING IN THE BOILER ROOM ........................................................................................................................................ 12
5.2. CASING PACKAGING ................................................................................................................................................................. 12
5.3. CASING ASSEMBLY ................................................................................................................................................................... 13
5.4. SHAKER LEVER ASSEMBLY ........................................................................................................................................................ 15
5.5. FLUE ......................................................................................................................................................................................... 15
5.5.1. CHIMNEY POT............................................................................................................................................................................................ 16
5.5.2. CHIMNEY HEIGHT ...................................................................................................................................................................................... 16
5.5.3. ROOF DRAIN WITH STEEL FLUE .................................................................................................................................................................. 17
5.5.4. ROOF DRAIN WITH TRADITIONAL FLUE ..................................................................................................................................................... 18
5.6. THERMAL EXHAUST VALVE CONNECTION ................................................................................................................................ 18
5.6.1. OPERATION OF THE THERMAL EXHAUST VALVE ........................................................................................................................................ 19
5.7. CORRECT SIZING OF THE BUFFER TANK .................................................................................................................................... 20
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6. . E EL LE EC CT TR RO ON NI IC C P PA AN NE EL L S SY Y 4 40 00 0 L LC CD D ( (C CO OD D. .P PE EL L0 01 10 00 0L LC CD DM MB B) ) . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 2 21 1
6.1. LCD KEYPAD ............................................................................................................................................................................. 21
6.2. LCD DISPLAY ............................................................................................................................................................................. 22
6.3. SY400 ELECTRONIC BOARD (INSIDE THE PANEL) ..................................................................................................................... 23
6.4. LAMBDA 100 ELECTRONIC BOARD ........................................................................................................................................... 24
6.5. PROBE CONNECTIONS ............................................................................................................................................................. 25
6.6. FLUE GAS PROBE CONNECTION ............................................................................................................................................... 25
6.7. TERMINAL BLOCK WIRING CONNECTIONS ............................................................................................................................... 26
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7. . D DI IS SP PL LA AY Y V VI IS SU UA AL LI IS SA AT TI IO ON N . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 2 27 7
7.1. KEYPAD LOCK ........................................................................................................................................................................... 27
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8. . O OP PE ER RA AT TI IO ON N . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 2 28 8
8.1. BOILER OFF .............................................................................................................................................................................. 28
8.2. BOILER IGNITION ...................................................................................................................................................................... 28
8.3. NORMAL OPERATION .............................................................................................................................................................. 29
8.4. MODULATION .......................................................................................................................................................................... 29
8.5. STANDBY .................................................................................................................................................................................. 29

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8.6. TOTAL SHUTDOWN .................................................................................................................................................................. 29
8.7. TIPS FOR PROPER FUNCTIONING ............................................................................................................................................. 30
8.7.1. LOADING THE WOOD ................................................................................................................................................................................ 30
8.7.2. USABLE FUELS ........................................................................................................................................................................................... 30
8.7.3. WARNINGS AND FUEL ADVICE ................................................................................................................................................................... 30
8.7.4. THE CORRECT STORAGE OF WOOD ........................................................................................................................................................... 31
8.7.5. COMBUSTION AIR REGULATION ................................................................................................................................................................ 31
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9. . U US SE ER R M ME EN NU U
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.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 3 32 2
9.1. BOILER THERMOSTAT MENU ................................................................................................................................................... 33
9.2. SUMMER - WINTER MENU ....................................................................................................................................................... 34
9.3. WATER SYSTEM MENU (ENABLE PROBES) ............................................................................................................................... 34
9.4. OUTPUTS TEST MENU .............................................................................................................................................................. 35
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10 0. . C CU US ST TO OM MI IS SA AT TI IO ON NS S M ME EN NU U . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 3 36 6
10.1. CUSTOMISATION – KEYPAD SETTING ....................................................................................................................................... 37
10.2. CUSTOMISATION – KEYPAD MENU .......................................................................................................................................... 38
10.3. CUSTOMISATION – SYSTEM MENU .......................................................................................................................................... 39
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11 1. . W WA AT TE ER R C CI IR RC CU UI IT T D DI IA AG GR RA AM MS S . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 4 40 0
11.1. INDICATIVE DIAGRAMS FOR CLOSED VESSEL HEATING SYSTEM WITH BUFFER TANK OR BUFFER TANK COMBI ...................... 40
11.1.1. INDICATIVE DIAGRAM FOR CLOSED VESSEL HEATING WITH BUFFER STORAGE TANK ................................................................................. 41
11.1.2. INDICATIVE DIAGRAM FOR CLOSED VESSEL HEATING WITH COMBI BUFFER TANK + SOLAR PANELS .......................................................... 42
11.1.3. INDICATIVE DIAGRAM FOR CLOSED-VESSEL HEATING WITH BUFFER TANK AND HYDRAULIC BOX FOR INSTANT DOMESTIC HOT WATER
PRODUCTION (CODE CASGID) ...................................................................................................................................................................... 43
11.1.4. INDICATIVE DIAGRAM FOR CLOSED-VESSEL HEATING WITH BUFFER TANK AND HYDRAULIC BOX WITH MIXING FOR RADIANT PANEL
SYSTEMS (CODE CASMIX) ............................................................................................................................................................................. 44
11.1.1. INDICATIVE DIAGRAM FOR CLOSED VESSEL HEATING WITH COMBI BUFFER TANK, SOLAR PANELS AND GAS BOILER ................................ 45
11.2. INDICATIVE DIAGRAMS FOR CLOSED VESSEL HEATING SYSTEM WITH DHW STORAGE CYLINDER AND BUFFER TANK ............. 47
11.2.1. INDICATIVE DIAGRAM FOR CLOSED VESSEL HEATING WITH BUFFER TANK + TWO-COIL DHW STORAGE CYLINDER AND SOLAR
PANELS ....................................................................................................................................................................................................... 48
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12 2. . C CE EN NT TR RA AL L H HE EA AT TI IN NG G S SY YS ST TE EM M C CO ON NN NE EC CT TI IO ON NS S T TO O “ “N N” ” Z ZO ON NE ES S
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.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 5 50 0
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13 3. . M MA AI IN NT TE EN NA AN NC CE E A AN ND D C CL LE EA AN NI IN NG G . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 5 52 2
13.1. DAILY CLEANING ...................................................................................................................................................................... 52
13.2. WEEKLY CLEANING ................................................................................................................................................................... 52
13.3. MONTHLY MAINTENANCE ....................................................................................................................................................... 52
13.4. ANNUAL MAINTENANCE (PERFORMED BY THE SERVICE CENTRE) ........................................................................................... 53
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14 4. . T TR RO OU UB BL LE ES SH HO OO OT TI IN NG G . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 5 54 4
14.1. ELECTRONIC CONTROL PANEL TROUBLESHOOTING ................................................................................................................ 54
14.2. BOILER TROUBLESHOOTING .................................................................................................................................................... 56
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15 5. . G GE EN NE ER RA AL L T TE EC CH HN NI IC CA AL L S SU UG GG GE ES ST TI IO ON NS S . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 5 56 6
15.1. CALIBRATIONS AND MAXIMUM TEMPERATURES .................................................................................................................... 56
15.2. FIRST IGNITION ........................................................................................................................................................................ 57
15.3. REFRACTORY CEMENTS INSIDE THE BOILER ............................................................................................................................. 57
15.4. BOILER AUTONOMY AND RECHARGE FREQUENCY .................................................................................................................. 57
15.5. EXPLOSIONS ............................................................................................................................................................................. 57
15.6. CONSUMABLES ........................................................................................................................................................................ 57
15.7. WARNINGS............................................................................................................................................................................... 57
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16 6. . C CH HO OO OS SI IN NG G T TH HE E M MO OD DE EL L . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 5 58 8
16.1. BOILER POWER ........................................................................................................................................................................ 58

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1. . G GE EN NE ER RA AL L W WA AR RN NI IN NG GS S
- This instruction booklet is an integral part of the product and must be provided to the user. Carefully read the
warnings contained in this booklet, as these provide important safety instructions for the installation, use and
maintenance of the product. This booklet should be carefully kept for future reference.
- Installation must be carried out by professionally qualified personnel or by an authorised service centre (in
compliance with Law 46/90) following the instructions provided by the manufacturer. The manufacturer is not
liable for any damage caused to people, animals or things due to incorrect installation.
- Make sure the product is intact. If in doubt do not use the product and contact the supplier. The parts of the
packaging must not be disposed of into the environment or left within the reach of children.
- Before performing any settings, maintenance or cleaning operations on the system, disconnect the appliance
from the mains power supply using the system switch or the corresponding on-off devices.
- In the event of faults or malfunctioning of the appliance or of the boiler, it should be deactivated. Do not attempt
to repair it. Contact professionally qualified personnel only. Any repairs must only be carried out by a
manufacturer’s authorised service centre, exclusively using original spare parts.
- Read this manual carefully before carrying out any work on the boiler.
- This booklet should be carefully kept for future reference.
- Connect the boiler to a 230V - 50Hz standard voltage power socket.
- Connect the boiler to the heating system; under no circumstances may the boiler be used without a hydraulic
connection and water charge.
- Check that the electrical system and sockets have the capacity to withstand the maximum power consumption of
the appliance stated in the manual.
- Some parts of the boiler, in particular the door, exhaust pipe, reach very high temperatures during operation;
avoid contact with such parts without suitable protection.
- Do not use flammable liquids or substances to ignite the boiler or rekindle the flame.
- The boiler must only be fired with fuels with the characteristics described in the manual.
- Ensure that the room where the boiler is to be installed is suitable and has minimum ventilation slots in
accordance with the regulations in force.
- Any unauthorised tampering, replacement and/or modification of boiler parts may cause harm to the user and
releases the manufacturer from any liability.
- Any tampering with, replacement or modification of the electronic part other than as described in the manual
will void the warranty.
- It is forbidden to modify safety or regulation devices.
- Do not use the boiler in any other way than intended.
IMPORTANT: the manufacture declines all liability, whether contractual or otherwise, for damage due to
improper installation or use and in any case failure to observe the instructions shown in this manual.
IMPORTANT: failure to heed the above warning may affect the effectiveness of the system or its individual
components, causing potential harm to the user. The manufacturer accepts no liability whatsoever in such
circumstances.
CAUTION: THE FIRST IGNITION AND TESTING OF THE BOILER MUST BE CARRIED OUT BY AN AUTHORISED
SERVICE CENTRE.

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1. .1 1. . P Pa ac ck ka ag gi in ng g a an nd d t tr ra an ns sp po or rt t
The boiler is delivered complete with all its electrical and mechanical components and factory tested.
Open the packaging and ensure that the boiler is complete and undamaged; if in doubt, contact the seller.
The installer is responsible for fitting the casing (see section 5.2.)
Disposal or recycling of the packaging is the responsibility of the end user.
The document envelope contains:
 boiler rating plate
 test certificate
 warranty
 user and installation manual
The boiler must always be moved in an upright position by means of manual or mechanical trolleys, which can lift the
pallet on which it is packed or directly the boiler itself.
The boiler is equipped with a lifting hook as shown in the figure.
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1. .2 2. . W Wa ar rr ra an nt ty y c co on nd di it ti io on ns s
The manufacturer guarantees the appliance, with the exception of the wear parts listed in section 1.3, for 24 months
on all electrical and mechanical components, 3 years on the steel boiler body only, 10 years on the stainless steel
boiler body only.
The warranty is only valid if tested by an authorised ARCA service centre and the accompanying warranty certificate is
filled out.
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1. .3 3. . W Wa ar rr ra an nt ty y l li im mi it ta at ti io on ns s
The warranty does NOT cover any parts that are damaged or defective due to incorrect use, negligence or careless
maintenance, incorrect installation or failure to comply with this manual.
The manufacturer accepts no liability for any damage that may occur to persons, property or animals as a result of
non-compliance with the rules and instructions written in this manual regarding installation, use and maintenance.
The warranty does not cover:
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- damage caused by the transport of the product;
- damage resulting from chemical, electro-chemical, atmospheric agents, fire, lightning, floods, glaciation,
earthquakes, natural disasters, defective electrical installations;
- damage to masonry;
- damage from the use of fuels that do not comply with what is described in the manual;
- damage caused by normal corrosion phenomena;
- damage to the electrical system, plumbing, or flue if the instructions in this manual are not followed;
- damage to the boiler body if no anti-condensation circuit is installed;
- damage caused by modifications or tampering with the electrical, hydraulic, mechanical part of the boiler and/or
other causes not resulting from the manufacture of the product;
- damage caused by the use of non-original spare parts.
- all routine cleaning and maintenance work, nor any activities to access the product such as removal of casings or
otherwise.
Furthermore, the warranty does not cover:
- parts subject to wear such as: refractory top (main stone), cement catalyst, bars.
- all parts subject to colour variations, coloured details, covers, handles and electrical cables.
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2. . T TE EC CH HN NI IC CA AL L S SP PE EC CI IF FI IC CA AT TI IO ON NS S A AN ND D S SI IZ ZE ES S
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2. .1 1. . T Te ec ch hn ni ic ca al l f fe ea at tu ur re es s a an nd d d di im me en ns si io on ns s A A2 25 5C CT TC CA A – – A A3 35 5C CT TC CA A - - A A5 50 0C CT TC CA A
Key:
1 Electronic panel A4 Safety heat exchanger connections
8 2-speed fan motor A5 Domestic hot water exchanger connections (only
ver. SA)
9 Blast door A6 Boiler probe thermowell connections (S4)
A1 System flow outlet A7 Boiler probe thermowell connection (S5)
A2
System return inlet
A8
Chimney connection
A3 Boiler drain A9 Flue gas probe thermowell connection

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SIZE
Model A
mm
B
mm
C
mm
D
mm
E
mm
F
mm
G
mm
A1 A2
ø
A3
ø
A4
ø
A5
ø
A6 A7
ø
A8
ø
Aspiro 25 CTCA 550 1,050 1,200 190 150 1,080 80 1” ¼ ½” ½” ½” ½” 150
Aspiro 35 CTCA 650 1,050 1,300 190 150 1,150 80 1”½ ½” ½” ½” ½” 180
Aspiro 50 CTCA 650 1,230 1,300 190 150 1,150 80 1”½ ½” ½” ½” ½” 180
TECHNICAL DATA
u.m.
Aspiro
25 CTCA
Aspiro
35 CTCA
Aspiro
50 CTCA
Nominal heat output (Qn) kW 24.08 31.30 41.14
Maximum firebox output kW 26.53 34.68 45.96
Minimum rated thermal output (Qmin) kW 16.86 21.91 28.80
Burning period (Tb) Hours 3.5 3.5 3
Flue gas temperature at rated power °C 140 140 140
Exhaust gas flow at rated power kg/s 0.0186 0.0222 0.0272
Minimum flue draught mbar 0.20 0.20 0.20
Boiler flue gas outlet diameter mm 150 180 180
Maximum operating pressure bar 4 4 4
Boiler body water content L 95 115 135
Mains voltage V 230 230 230
Frequency Hz 50 50 50
Electrical consumption at rated power W 122 122 182
Boiler weight kg 380 470 555
Class ref. UNI EN 303-5:2012 5 5 5
Efficiency at rated power % 90.78 90.24 89.51
Environmental classification stars
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3. . M MA AI IN N P PA AR RT TS S O OF F T TH HE E B BO OI IL LE ER R
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3. .1 1. . W Wo oo od d s st to or ra ag ge e c ch ha am mb be er r
It is the tank of the wood boiler. In this compartment, which is located in the upper part of the boiler, wood logs are
loaded after ignition and the production of embers.
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3. .2 2. . M Ma ai in n s st to on ne e a an nd d b ba ar rs s
In the central part of the boiler between the wood storage chamber and the lower exchange area, the main refractory
concrete stone is positioned, which has a longitudinal slit in the centre with a recess to house the grid plate. The latter
is composed of elements called bars, made of refractory cement, whose function is to support the embers and,
through the central slits, to allow the passage of combustible gas.
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3. .3 3. . E Ex xc ch ha an ng ge e z zo on ne e a an nd d c ca at ta al ly ys st t
The wood gas, as it passes through the bars, produces a flame that, developing downwards, grazes a refractory
concrete conveyor, known as the lower firebox.
The flame, passing through a high-temperature zone, promotes the elimination of the remaining unburnt carbon
particles. As the combustion gases pass through the vertical rear exchange zone, they release heat to the water.

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3. .4 4. . S Sm mo ok ke eb bo ox x a an nd d f fa an n
The combustion gas, after having given up energy to the water, accumulates inside the smokebox located at the rear
of the boiler. The smokebox houses the two-speed fan, fitted horizontally and consisting of an electric motor and
impeller. The fan allows easy maintenance, being secured in place using wing nuts.
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3. .5 5. . A Ai ir r d di is st tr ri ib bu ut ti io on n u un ni it t
At the front of the boiler, between the upper and lower door, is the combustion air intake. The inlet duct is equipped
with an internal, gravity-driven clapet valve that closes when the fan stops.
The air entering the unit is divided into primary and secondary. The primary air goes to the wood storage chamber
and, mixing with the distilled gas, creates the combustible mixture, which burns through the grid plate. Secondary air,
on the other hand, passes through the two cavities of the main stone and the bars, providing an injection of oxygen
directly into the flame formation zone, thereby optimising combustion. The secondary air is then regulated by the
front servomotor, which takes its movement signal via the oxygen percentage reading from the lambda sensor located
in the smoke box.
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3. .6 6. . D DH HW W e ex xc ch ha an ng ge er r ( (S SA A v ve er rs si io on ns s o on nl ly y) )
The Aspiro CTCA boiler can be equipped with an internal instantaneous heat exchanger for the production of domestic
hot water (SA models only). The heat exchanger consists of a copper tube immersed in the water jacket, around the
body of the wood boiler, with the inlet and outlet plumbing connections at the rear of the boiler.
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3. .7 7. . S Sa af fe et ty y h he ea at t e ex xc ch ha an ng ge er r
The boiler is equipped as standard with a safety heat exchanger for the wood-fired part. Its function is to cool the
boiler in the event of overtemperature by means of a thermal exhaust valve hydraulically connected to the heat
exchanger inlet (see section 5.6). It consists of a steel coil with an inlet and outlet at the rear of the wood boiler (A4
connections). The sensing element of the thermal exhaust valve is positioned in connection A6.
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3. .8 8. . W Wa at te er r t te em mp pe er ra at tu ur re e p pr ro ob be e t th he er rm mo ow we el ll ls s
At the top of the boiler are two identical thermowells (A6) both with a ½” coupling, and with the following functions:
 housing for the copper sheath that holds the probes connected to the electronic control panel;
 free housing for a second copper sheath or temperature measuring device (thermal relief valve)
Key:
1 Wood storage chamber
2 Burner grid plate
3 Primary air inlet
4 Secondary air inlet
5 Combustion zone
6 Exchange zone
7 Fan motor
8 Mobile turbulators

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3
3. .9 9. . R Re ec ci ir rc cu ul la at ti in ng g p pu um mp p ( (a an nt ti i- -c co on nd de en ns sa at ti io on n) )
To minimise the possibility of condensate forming in the wood-fired boiler, a recirculating pump needs to be installed.
The pump is connected between the outlet (A1) and return (A2) fittings, with the direction of flow from top down.
ARCA supplies a recirculating pump kit as an accessory, including pump, connection piping and fittings.
IMPORTANT: For correct generator operation the recirculating pump must be installed.
THE WARRANTY WILL BE VOID IF THE RECIRCULATING PUMP IS NOT INSTALLED.
3
3. .1 10 0. . I In ns su ul la at ti io on n
The Aspiro CTCA boiler is insulated by a 60 mm thick layer of mineral wool placed in contact with the boiler body, in
turn protected by the outer casing, made from epoxy powder coated steel panels.
3
3. .1 11 1. . S Su up pp pl ly y w wa at te er r
For correct operation and safety of the central heating system information must be available on the chemical-physical
characteristics of the system and top-up water. The main problem caused by using very hard water is fouling of the
heat exchange surfaces. It is well-known that high concentrations of calcium and magnesium carbonates (lime scale)
precipitate when heating, forming scale. These lime deposits have low thermal conductivity and consequently prevent
heat exchange, creating localised overheating that weakens the metal structures, leading to breakage. It is therefore
recommended to adopt water treatment in the following cases:
 very hard top-up water (over 20°f)
 high capacity (large) systems
 frequent topping up due to leaks
 frequent filling due to maintenance on the system.
IMPORTANT: if the boiler is used as a replacement in an existing system, this should be washed chemically
beforehand using basic dispersants.
4
4. . T TY YP PE E O OF F O OP PE ER RA AT TI IO ON N
The Aspiro CTCA boiler is a biomass boiler running on wood, using the traditional method of wood gasification with a
reversed flame.
4
4. .1 1. . G Ga as si if fi ic ca at ti io on n t te ec ch hn no ol lo og gy y
The Aspiro CTCA boiler bases its operation on the principle of gasification (or distillation) of wood. The solid fuel,
placed in the upper compartment of the boiler (wood storage chamber), in contact with the embers produced on the
grid plate develops gases that combine with the combustion air (primary air) to create a combustible mixture. This
mixture is drawn through the grid plate slits into the lower area of the firebox (exchange zone) where it will give rise
to the characteristic 'upturned flame'.
Gasification, by not burning wood directly, but using the gases contained in it, allows total exploitation of the solid
fuel, meaning high combustion efficiency and a very low environmental impact due to the absence of unburnt and
harmful substances in the fumes.
The Aspiro CTCA boiler is designed to minimise the negative effects of acid condensation. The firebox is 8 mm thick in
the steel version and 5 mm thick in the stainless steel version, and is seamless in the upper area of the wood storage
chamber.

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5
5. . I IN NS ST TA AL LL LA AT TI IO ON N
The Aspiro CTCA boiler is no different from a normal solid fuel boiler; therefore, there are no specific installation
instructions beyond the safety requirements of the relevant standards in force. The room must be well-ventilated;
ventilation openings must have a minimum total surface area no less than 0.5 m2. To simplify cleaning of the flue gas
circuit, a free space no less than the length of the boiler should be left at the front, making sure that the door can
open 90° without being obstructed.
The boiler can rest directly on the floor, as it comes with a self-supporting frame. Nonetheless, in very damp boiler
rooms, a concrete base is recommended. Once installation is complete, the boiler must be perfectly horizontal and
stable so as to reduce any vibrations and noise.
5
5. .1 1. . P Po os si it ti io on ni in ng g i in n t th he e b bo oi il le er r r ro oo om m
Aspiro CTCA Generators must be installed in the boiler room in compliance with the relevant legislation in force (for
further details contact your local fire station).
The distances for positioning the boiler in the boiler room are illustrated below.
5.2. Casing packaging
The Aspiro Monomatic boiler is delivered dismantled: the casing and the casing accessory kit are packed separately in
cardboard boxes.
CASING PACKAGING:
Key:
1 Packaging cardboard
2 Accessory bag
3 Right side panel
4 Boiler body insulation
5 Lid
6 Left side panel
7 Front centre cover plate
8 Lower back
9 Lower front door cover
10 Upper front door cover
11 Upper back

13
CASING KIT PACKAGING:
5.3. Casing assembly
 Position generator 1 in the boiler room and make the hydraulic connections.
 Wrap the boiler body with the rockwool insulation mat 2 and secure it with the clamps 3.
 Screw the blast doors to the base of the smoke chamber 4.
 Install the fan 5 in the smoke box housing.
 Position the casing sides 6 and 7, taking care to insert the upper fold into the slots on the top of the plates, and
the lower fold into the base angle of the boiler.
 Place the cover 8 on the side panels 6 and 7, taking care to match the pins on the side panels to the clip holes in
the cover itself, and fit them by applying light pressure
 Attach control panel 9 to cover 10, unwind the thermostat capillaries and pass them under the cover through the
hole provided. When unwinding the capillaries, care must be taken to ensure that they are not bent in such a way
that they present very sharp curves, which would prevent the normal expansion/reduction of the heat-sensitive
substance inside them; always try to unwind the capillaries in such a way that they present slight curves.
 Place cover 10 on side panels 6 and 7, taking care to match the pins on the side panels to the holes provided with
clips on the cover itself, and fit them with light pressure.
 Fasten the protective panel 11 to the wood storage chamber door, not before screwing in the handle M.
 Attach protective panel 12 to the lower door, not before screwing in knob P.
 Mount the rear panels 14 and 15 by fixing them to the pins on the side panels 6 and 7
 Insert lever 16 for cleaning the mobile turbulators on the pin on the side of the smoke box, securing it with the
hexagon screw provided.
 Mount the door as shown:
- Insert door 8 into the screw that serves as the pin of bracket B.
- Bring door 8 closer to bracket A and fasten the screw that should centre hole X symmetrical to the hole
centred in the previous step.
- Check that the door 8 rotates properly and secure the cover 9 by inserting the pegs into the springs with
light pressure.
Key:
1 Packaging cardboard
2 Upper door cover
3 Spacers
4 Upper back
5 Lower back
6 Front door
7 Lower horizontal back
8 Upper horizontal back
9 Right rear side panel
10 Left rear side panel

14

15
5
5. .4 4. . S Sh ha ak ke er r l le ev ve er r a as ss se em mb bl ly y
5
5. .5 5. . F Fl lu ue e
The chimney plays a fundamental role in ensuring good boiler operation: the chimney must be impermeable and well-
insulated. Old or new chimneys not built in compliance with the above specifications can be used, but with special
modifications. A metal flue needs to be inserted inside the existing chimney, and the space between the metal flue
and the chimney has to be filled with special insulation. Chimneys made from prefabricated blocks must have
perfectly sealed joints to prevent condensate in the flue gas from fouling the walls due to absorption.
We strongly recommend the use of a flue pipe that complies with current standards, and in particular with EN 1806,
which require resistance to a flue gas temperature of up to 1000°C. The user is liable for damage caused by the use of
unsuitable rods.
In any case, the chimney must feature good draught, equal to at least 15 Pa of negative pressure at the base.
Chimneys with insufficient draught will cause the wood boiler to shut down when the system is not operating, with tar
and condensate forming along the air inlet. Vice-versa, a chimney with excessive natural draught will cause problems
of thermal inertia as well as high wood consumption.
A draught regulator should always be installed so as to maintain constant negative pressure in the chimney. This will
avoid any unwanted increases in heat output.
WARNINGS
 the flue must have a pipe diameter no smaller than that of the boiler outlet connection.
 the flue must be as vertical as possible.
 the flue must be perfectly sealed to prevent it from cooling down.
 the flue must have a constant, free, independent internal cross-section, free of bottlenecks.
 flue pipes must not pass through rooms in which the installation of combustion appliances is prohibited.
 hoses are not permitted.
 a 'T' pipe must be installed immediately after the boiler outlet so that residues can be cleaned out periodically.
 a collective flue cannot be used.
 only exhaust ducts suitable for the type of fuel used must be used.
 avoid the construction of completely horizontal sections.
 The room in which the boiler is to be installed must not have an extraction hood.
 direct wall exhaust is not permitted.
 install an inspection valve to allow any condensate that may have formed to drain away.
 use a rainproof and windproof terminal.
On the side of the casing there is a hole
where you can insert the lever for cleaning
the mobile turbulators to be mounted on the
pin on the side of the smoke box, securing it
with the appropriate hexagon screw.
The shaker pin can be mounted on either the
right or left side.
SHAKER PIN

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5
5. .5 5. .1 1. . C Ch hi im mn ne ey y p po ot t
The chimney pot must meet the following requirements:
 have a cross-section and internal shape equivalent to that
of the flue;
 have a useful outlet cross-section not less than twice that
of the flue;
 be constructed in such a way as to prevent the penetration
of rain, snow and foreign bodies and, in the event of
winds, ensure the normal flow of smoke;
 be positioned so as to ensure adequate dispersion and
dilution of combustion products and in any case outside
the reflux zone.
5
5. .5 5. .2 2. . C Ch hi im mn ne ey y h he ei ig gh ht t
The height of the part of the chimney projecting from the roof depends on the type of roof, its slope and its position.
FLAT ROOF
SLOPING ROOF
ROOF PITCH REFLUX ZONE DISTANCE BETWEEN RIDGE
AND CHIMNEY MINIMUM CHIMNEY HEIGHT
β m A H
15° 0.50m ≤ 1.85m 0.50m over the ridge
> 1.85m 1.00 m from the roof
30° 0.80m ≤ 1.30m 0.50m over the ridge
> 1.30m 1.20m from the roof
45° 1.50m ≤ 1.50m 0.50m over the ridge
> 1.50m 2.00m from the roof
60° 2.10m ≤ 1.20m 0.50m over the ridge
> 1.20m 2.60m from the roof

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5
5. .5 5. .3 3. . R Ro oo of f d dr ra ai in n w wi it th h s st te ee el l f fl lu ue e
When installing the flue, always ensure an inspection valve for periodic soot cleaning and evacuation of any
condensate.
If the flue gas duct is to be installed completely outdoors, it should be made completely of double-walled stainless
steel to ensure better weather resistance and adequate flue gas discharge temperature.

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5
5. .5 5. .4 4. . R Ro oo of f d dr ra ai in n w wi it th h t tr ra ad di it ti io on na al l f fl lu ue e
Combustion gases can also be evacuated using an existing traditional flue as long as it is built to standard.
It must comply with the following rules:
 must be provided with adequate insulation in the exposed outer section;
 the internal section must be constant;
 must be made of material that is resistant to high temperatures, the action of combustion products and any
condensation that may form;
 predominantly vertical course with deviation from the axis not exceeding 45°;
 must be equipped with a soot and condensate collection chamber that can be inspected through a door.
5
5. .6 6. . T Th he er rm ma al l e ex xh ha au us st t v va al lv ve e c co on nn ne ec ct ti io on n
IMPORTANT: it is recommended to install
a thermal relief valve in the coil input and
a drain pipe near the heat exchanger
outlet.
DRAIN
INLET
COLD WATER

19
Note: the thermal relief valve could also be placed on the used hot water outlet, but this would not be
beneficial from a safety point of view and you would run the risk that the sediments in the heat exchanger
interfere with correct operation of the valve itself.
5
5. .6 6. .1 1. . O Op pe er ra at ti io on n o of f t th he e t th he er rm ma al l e ex xh ha au us st t v va al lv ve e
The valve, regardless of pressure, opens when the temperature of the primary circuit reaches approximately 95°C.
Opening the valve results in a constant discharge of water, which prevents the temperature from reaching 110°C.
Note: it is recommended to test the safety valve once installed by bringing the boiler to the valve opening
temperature.
It is absolutely forbidden to produce domestic hot water by means of the safety heat exchanger. The heat exchanger
must be permanently connected to a thermal safety valve and must be able to intervene with maximum efficiency to
cool the boiler in an emergency.
CORRECT
INSTALLATION WRONG
INSTALLATION
Drain
Cold water
inlet
Drain
Cold water
inlet

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5
5. .7 7. . C Co or rr re ec ct t s si iz zi in ng g o of f t th he e b bu uf ff fe er r t ta an nk k
The boiler installation always includes the connection to the system of a buffer tank (thermal flywheel), consisting of a
storage tank, with thermal insulation, in which the water heated by the boiler circulates.
This allows rapid temperature increases or decreases to be absorbed, increasing the system's operating range.
In the Aspiro 25/35/50 CTCA wood boiler, the fuel cannot be metered as in a pellet, gas or oil boiler, so once loaded it
must be consumed in one go. In modulation steady state operation, the minimum power output is 30% higher than
the nominal heat output, therefore, it is necessary to install a correctly dimensioned buffer tank according to EN 303-
5:2012 (paragraph 4.4.6) which provides the following calculation formula:
Vsp = 15 TB QN (1-0,3QH/Qmin) (in litres)
Where:
 Vsp is the volume of the storage tank in litres;
 QN is the rated output of the boiler in kilowatts;
 TB is the burning period in hours;
 QH is the heat demand of the installation site in kilowatts (a value that depends on the building's
dispersion and must be assessed by the heating engineer);
 Qmin is the minimum boiler output in kilowatts.
Aspiro 25 CTCA Aspiro 35 CTCA Aspiro 50 CTCA
QN - Boiler nominal output 24.08 kW 31.3 kW 41.14 kW
TB - Burning period 3.5 h 3.5 h 3 h
Qmin- Minimum boiler output 16.8 kW 21.9 kW 28.8 kW
The volume of the storage tank therefore depends on both the boiler characteristics (table above) and the 'thermal'
characteristics of the building (QH ) served by the boiler. The table below shows the minimum storage volumes to be
provided depending on the value of the building's energy demand in the cases of 100%; 80% and 50% QN:
Buffer tank sizing for Aspiro 25, 35 and 50 CTCA according to EN 303-5:2012
Boiler model V with Qh=Qn Litres/kW V with Qh=80%Qn Litres/kW V with Qh=50%Qn Litres/kW
Aspiro 25 CTCA 722 30 831 35 993 41
Aspiro 35 CTCA 939 30 1080 35 1291 41
Aspiro 50 CTCA 1058 26 1217 30 1455 35
The closer the boiler output is to the building's energy demand, the smaller the volume of the storage tank will be. It is
therefore advisable that the designer does not tend to oversize the generator because this would result in having to
install large tanks with a consequent increase in system costs.
Caution: in order to obtain Conto Termico 2.0. incentives, the storage tank must comply with EN 303-5:2012
and must be dimensioned as above.