ARCA GRANOLA AUTOMATIC Series Specification sheet

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
G
GR RA AN NO OL LA A
A
AU UT TO OM MA AT TI IC C

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ARCA s.r.l. declines all liability for any imprecisions due to transcription or printing errors. It likewise
reserves the right to make any changes to its products that it considers necessary or useful, without
these affecting the essential features of such products. This documents is also available as a PDF file.
To request a copy contact the ARCA s.r.l. technical department.
code: MAN1037
pages: 48
edition: V EDITION
revision: June 2010

4
C
CO ON NT TE EN NT TS S
1. GENERAL WARNINGS ..............................................................................................................................6
2. TECHNICAL SPECIFICATIONS AND DIMENSIONS .................................................................................7
2.1. TECHNICAL SPECIFICATIONS AND DIMENSIONS OF MODELS GRA14RO,GRA20RO, GRA30RO ................7
2.2. TECHNICAL SPECIFICATIONS AND DIMENSIONS OF MODELS GRA40RO, GRA50RO ..................................8
2.3. TECHNICAL SPECIFICATIONS AND DIMENSIONS OF MODELS GRA80RO ..................................................... 9
2.4. TECHNICAL SPECIFICATIONS AND DIMENSIONS OF MODELS GRA115RO, GRA150RO ..............................9
3. MAIN PARTS OF THE BOILER ................................................................................................................10
3.1. FUEL FEED SCREW FOR MODELS GRANOLA 14, 20, 30, 40, 50.....................................................................10
3.2. SCREW (CODE COC0502) FOR MODELS GRA80RO, GRA115RO & GRA150RO............................................ 11
3.3. TANK (CODE CON0600) FOR MODELS GRA80RO, GRA115RO & GRA150RO ...............................................11
3.4. PELLET BURNER.................................................................................................................................................12
3.5. BOILER HEAT EXCHANGER AND FURNACE ....................................................................................................12
3.6. SMOKEBOX AND FAN .........................................................................................................................................13
3.7. WATER TEMPERATURE PROBE SOCKETS......................................................................................................13
3.8. RECIRCULATING PUMP (ANTI-CONDENSATION) ............................................................................................13
3.9. SUPPLY WATER ..................................................................................................................................................13
3.10. INSULATION.........................................................................................................................................................13
4. INSTALLATION.........................................................................................................................................14
4.1. POSITIONING IN THE BOILER ROOM ................................................................................................................14
4.2. EXPANSION VESSELS ........................................................................................................................................14
4.3. CHIMNEY..............................................................................................................................................................14
5. SY400 ELECTRONIC PANEL (CODE PEL0100DUO)..............................................................................15
5.1. DISPLAY ...............................................................................................................................................................15
5.2. ELECTRONIC BOARD .........................................................................................................................................16
5.3. PROBE CONNECTIONS ......................................................................................................................................17
5.4. FLUE GAS PROBE CONNECTION ......................................................................................................................17
5.5. TERMINAL BLOCK WIRING CONNECTIONS .....................................................................................................18
6. COMMISSIONING AND OPERATION ......................................................................................................19
6.1. BOILER IN STANDBY...........................................................................................................................................19
6.2. BOILER IGNITION ................................................................................................................................................19
6.3. FLAME STABILISATION.......................................................................................................................................19
6.4. NORMAL OPERATION.........................................................................................................................................20
6.5. BOILER TEMPERATURE SETTING.....................................................................................................................20
6.6. MODULATION ......................................................................................................................................................20
6.7. MAINTENANCE ....................................................................................................................................................20
6.8. TOTAL SHUTDOWN.............................................................................................................................................21
7. USER MENU.............................................................................................................................................21
7.1. WATER CIRCUIT CONFIGURATION MENU (ENABLE PROBES .......................................................................22
7.2. DISPLAY MENU (DISPLAY PROBE READINGS) ................................................................................................23
7.3. CLOCK MENU ......................................................................................................................................................25
7.4. TIMER PROGRAMMING MENU........................................................................................................................... 26
7.5. MANUAL SCREW LOADING MENU.....................................................................................................................31
7.6. TEST MENU..........................................................................................................................................................31
7.7. SUMMER / WINTER OPERATION .......................................................................................................................34
8. WATER CIRCUIT DIAGRAMS..................................................................................................................34
8.1. EXAMPLE DIAGRAMS FOR HEATING-ONLY SYSTEM WITH OPEN VESSEL .................................................34
8.1.1. EXAMPLE DIAGRAM FOR HEATING-ONLY WITH OPEN VESSEL .......................................................................................35
8.1.2. EXAMPLE DIAGRAM FOR HEATING-ONLY WITH OPEN VESSEL WITH MIXING VALVE ..................................................35
8.1.3. EXAMPLE DIAGRAM FOR HEATING-ONLY WITH PLATE HEAT EXCHANGER ..................................................................36
8.2. EXAMPLE DIAGRAMS FOR HEATING SYSTEM WITH DOMESTIC HOT WATER STORAGE CYLINDER.......36
8.2.1. EXAMPLE DIAGRAM FOR HEATING WITH DOMESTIC HOT WATER STORAGE CYLINDER ............................................37
8.2.2. EXAMPLE DIAGRAM FOR HEATING WITH TWO-COIL DHW STORAGE CYLINDER AND SOLAR PANELS .................... 38

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8.2.3. EXAMPLE DIAGRAM FOR HEATING WITH CLOSED VESSEL, PLATE HEAT EXCHANGER, TWO-COIL DHW
STORAGE CYLINDER AND SOLAR PANELS .........................................................................................................................38
8.3. EXAMPLE DIAGRAMS FOR HEATING SYSTEM WITH BUFFER TANK OR COMBI BUFFER TANK................39
8.3.1. EXAMPLE DIAGRAM FOR HEATING WITH COMBI BUFFER TANK AND SOLAR PANELS.................................................40
8.3.2. EXAMPLE DIAGRAM FOR HEATING WITH CLOSED VESSEL, PLATE HEAT EXCHANGER, COMBI BUFFER TANK
AND SOLAR PANELS...............................................................................................................................................................40
8.4. EXAMPLE DIAGRAMS FOR HEATING SYSTEM WITH DOMESTIC HOT WATER STORAGE CYLINDER
AND BUFFER TANK.............................................................................................................................................41
8.4.1. EXAMPLE DIAGRAM FOR WITH BUFFER TANK, TWO-COIL DHW STORAGE CYLINDER AND SOLAR PANELS ...........42
9. CENTRAL HEATING SYSTEM CONNECTION TO “N” ZONES ...............................................................43
10. MAINTENANCE AND CLEANING ............................................................................................................44
10.1. WEEKLY CLEANING ............................................................................................................................................44
10.2. MONTHLY MAINTENANCE..................................................................................................................................44
12.3. ANNUAL MAINTENANCE (PERFORMED BY THE SERVICE CENTRE)............................................................. 45
11. TROUBLESHOOTING ..............................................................................................................................45
11.1. CONTROL PANEL TROUBLESHOOTING ...........................................................................................................45
11.2. BOILER TROUBLESHOOTING ............................................................................................................................46

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1. GENERAL WARNINGS
This instruction booklet is an integral and essential 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.
The appliance must be installed by professionally qualified personnel or by our service centre in compliance
with local legislation in force and 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 complete. In case of 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, disconnect the appliance from the
mains power supply using the system switch and/or the corresponding on-off devices.
In the event of faults and/or malfunctioning of the appliance, it should be deactivated. Do not attempt to repair
the appliance. Contact professionally qualified personnel only. Any repairs must only be carried out by a
manufacturer’s authorised service centre, exclusively using original spare parts.
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.
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.
WARNING !
The boiler must be commissioned and tested by an authorised service centre.

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2. TECHNICAL SPECIFICATIONS AND DIMENSIONS
2.1. Technical specifications and dimensions of models GRA14RO, GRA20RO and
GRA30RO
Key:
1 Fuel container (granular fuel storage) A1 Central heating flow outlet
2 Fuel inlet A2 Central heating return inlet
3 Flame inspection opening A3 Boiler drain
4 Top door (furnace) A4 Safety heat exchanger attachments
5 Burner cover plate A5 Boiler probe socket attachment (S4)
6 Bottom door (ash dump) A6 Chimney attachment
7 Cleanout door A7 Thermal relief valve socket attachment
8 Fan motor (flue gas exhaust) A8 Boiler probe socket attachment (S5)
9 Fuel container screw gear motor (fuel
supply)
Model
Minimum
heat
output
kcal/h
kW
Maximum
heat
output
kcal/h
kW
Minimum
heat
input
kcal/h
kW
Maximum
heat
input
kcal/h
kW
Weight
kg
Fuel
container
capacity
kg
Boiler
capacity
litres
Water side
pressure
drop
mbar.
Flue gas
side
pressure
drop
mbar.
Operating
pressure
bar.
Max test
pressure
bar.
GRA14RO 5.040
6
12.068
14
6.020
7
13.330
15,5 200 110 47 10 0.03 3 4.5
GRA20RO 8.600
10
17.200
20
9.460
11
18.920
22 200 110 47 10 0.03 3 4.5
GRA30RO 17.200
20
25.800
30
18.920
22
28.380
33 280 196 68 10 0.03 3 4.5
Model A
mm
B
mm
B1
mm
C
mm
C1
mm
C2
mm
L
mm
H
mm
F
mm
G
mm
A1 A2
ø
A3
ø
A4
ø
A5
ø
A6
ø
A7
ø
A8
ø
GRA14RO 550 1237 770 1460 632 180 243 575 475 135 1” ½” ½” ½” 99 ½” ½”
GRA20RO 550 1237 770 1460 632 180 243 575 475 135 1” ½” ½” ½” 99 ½” ½”
GRA30RO 620 1310 900 1600 830 180 260 715 560 170 1” ¼ ½” ½” ½” 138 ½” ½”

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2.2. Technical specifications and dimensions of models GRA40RO and GRA50RO
Key:
1 Fuel container (granular fuel storage) A1 Central heating flow outlet
2 Fuel inlet A2 Central heating return inlet
3 Flame inspection opening A3 Boiler drain
4 Top door (furnace) A4 Safety heat exchanger attachments
5 Burner cover plate A5 Boiler probe socket attachment (S4)
6 Bottom door (ash dump) A6 Chimney attachment
7 Cleanout door A7 Thermal relief valve socket attachment
8 Fan motor (flue gas exhaust) A8 Boiler probe socket attachment (S5)
9 Fuel container screw gear motor (fuel
supply)
Model
Minimum
heat
output
kcal/h
kW
Maximum
heat
output
kcal/h
kW
Minimum
heat
input
kcal/h
kW
Maximum
heat
input
kcal/h
kW
Weight
kg
Fuel
container
capacity
kg
Boiler
capacity
litres
Water side
pressure
drop
mbar.
Flue gas
side
pressure
drop
mbar.
Operating
pressure
bar.
Max test
pressure
bar.
GRA40RO 25800
30
34400
40
28380
33
37840
44 370 280 117 10 0.06 3 4.5
GRA50RO 34400
40
43000
50
37840
44
47300
55 370 280 117 10 0.06 3 4.5
Model A
mm
B
mm
B1
mm
C
mm
C1
mm
L
mm
H
mm
F
mm
G
mm
A1 A2
ø
A3
ø
A4
ø
A5
ø
A6
ø
A7
ø
A8
ø
GRA40RO 690 1510 1100 1780 830 260 880 763 192 1” ¼ ½” ½” ½” 150 ½” ½”
GRA50RO 690 1510 1100 1780 830 260 880 763 192 1” ¼ ½” ½” ½” 150 ½” ½”

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2.3. Technical specifications and dimensions of models GRA80RO
Key:
1 Fuel inlet A2 Central heating return inlet
2 Flame inspection opening A3 Boiler drain
3 Top door (furnace) A4 Safety heat exchanger attachments
4 Burner cover plate A5 Boiler probe socket attachment (S4)
5 Bottom door (ash dump) A6 Chimney attachment
6 Cleanout door A7 Thermal relief valve socket attachment
7 Fan motor (flue gas exhaust) A8 Boiler probe socket attachment (S5)
A1 Central heating flow outlet A9 Available for cleaning accessories
Model
Minimu
m heat
output
kcal/h
kW
Maximu
m heat
output
kcal/h
kW
Minimum
heat
input
kcal/h
kW
Maximum
heat
input
kcal/h
kW
Weight
kg
Boiler
capacity
litres
Water side
pressure
drop
mbar.
Flue gas
side
pressure
drop
mbar.
Operating
pressure
bar.
Max test
pressure
bar.
GRA80RO 60200
70
68800
80
66220
77
75680
88 400 190 5 0.03 3 4.5
Model A
mm
B
mm
C
mm
D
mm
H
mm
F
mm
G
mm
E
mm
L
mm
A1 A2
ø
A3
ø
A4
ø
A5
ø
A6
ø
A7
ø
A8
ø
A9
ø
GRA80RO 768 1120 1129 190 1035 870 380 376 260 1” ¼ ½” ½” ½” 178 ½” ½” 28
2.4. Technical specifications and dimensions of models GRA115RO and GRA150RO
Key:
1 Fuel inlet A3 Boiler drain
2 Flame inspection opening A4 Safety heat exchanger attachments
3 Top door (furnace) A5 Boiler probe socket attachment (S4)
4 Burner cover plate A6 Chimney attachment
5 Bottom door (ash dump) A7 Thermal relief valve socket attachment
6 Cleanout door A8 Boiler probe socket attachment (S5)
7 Fan motor (flue gas exhaust) A9 Available for cleaning accessories
A1 Central heating flow outlet A10 Recirculating pump attachment (anti-condensation)
A2 Central heating return inlet

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Model
Minimu
m heat
output
kcal/h
kW
Maximu
m heat
output
kcal/h
kW
Minimum
heat
input
kcal/h
kW
Maximum
heat
input
kcal/h
kW
Weight
kg
Boiler
capacity
litres
Water side
pressure
drop
mbar.
Flue gas
side
pressure
drop
mbar.
Operating
pressure
bar.
Max test
pressure
bar.
GRA115RO 77400
90
94600
110
85140
99
98900
115 560 276 10 0.05 3 4.5
GRA150RO 103200
120
129000
150
113520
132
141900
165 670 362 12 0.05 3 4.5
Model A
mm
B
mm
C
mm
D
mm
H
mm
F
mm
G
mm
E
mm
L
mm
A1 A2
ø
A3
ø
A4
ø
A5
ø
A6
ø
A7
ø
A8
ø
A9
ø
A10
ø
GRA115RO 862 1130 1352 190 1253 1030 350 376 260 2’’ ½”
3/4” ½” 200 ½” ½” 28 1”
GRA150RO 862 1480 1352 190 1253 1030 350 376 260 2’’ ½”
3/4” ½” 200 ½” ½” 28 1”
3. MAIN PARTS OF THE BOILER
3.1. Fuel feed screw for models GRANOLA 14, 20, 30, 40, 50
Ke
y
:
1. Screw gear motor
2. Pellet container
3. Fuel feed screw
4. Pellet burner
The fuel container located
above the boiler bod
y
includes
the feed screw; this is
mana
g
ed automaticall
y
b
y
the
electronic panel based on the
parameter settings.
TOP VIEW (CONTAINER LOCATED
ABOVE THE BOILER BODY)

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3.2. Screw (CODE COC0502) for models GRA80RO, GRA115RO, GRA150RO
In versions 80, 115 and 150 the screw is supplied separately.
Versions 30, 40, 50 can be supplied with the fuel container and screw separately on request.
1694
1920
1
2
2
3.3. Tank (CODE CON0600) for models GRA80RO, GRA115RO, GRA150RO
When startin
g
the boiler for the first time the
screw should be powered directly (USER MENU
- “LOAD”) so as to load the screw and ensure a
regular flow of fuel, thus optimising boiler
operation.
Ke
y
:
1. Screw gear motor
2. Fuel feed screw
WARNING
for correct screw operation this
should be kept at the maximum
possible incline.

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3.4. Pellet burner
Key:
1 Photocell 5 Power outlet for boiler panel connection
2 Secondary air adjustment 6 Door for primary air adjustment
3 Ignition heater 7 Flame inspection opening cover
4 Stainless steel perforated grid plate 8 Pellet inlet
3.5. Boiler heat exchanger and furnace
Key:
1 Screw 9 Ash dump
2 Fuel supply 10 Smokebox
3 Flame inspection opening 11 Fan
4 Secondary air 12 Furnace with dry heat exchanger
5 Ignition heater 13 Flue gas outlet
6 Electric heater housing 14 Dry heat exchanger
7 Primary air 15 Safety heat exchanger
8 Burner draught tube
WARNING:
The cover on inspection
opening 7 must be kept
closed during ignition
and shut-down.

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3.6. Smokebox and fan
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.
3.7. Water temperature probe sockets
At the rear of the boiler are two identical sockets, A5 and A7, both with a 1/2" coupling, and have the
following function:
 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).
3.8. Recirculating pump (anti-condensation)
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.
For correct boiler operation the recirculating pump must be installed.
THE WARRANTY WILL BE VOID IF
THE RECIRCULATING PUMP IS NOT INSTALLED
3.9. Supply water
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’s 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 weaken the metal
structures, leading to breakage. It’s 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 alkaline dispersants.
3.10. Insulation
The Granola automatic 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.

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4. INSTALLATION
The Granola AUTOMATIC 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 reduce any vibrations and noise.
4.1. Positioning in the boiler room
The boiler 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.
4.2. Expansion vessels
In accordance with standards in force (in Italy), solid fuel boilers with manual loading must be installed in
systems fitted with “open” expansion vessels. For automatic loading, systems with closed vessels are
permitted.
4.3. Chimney
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,
however with special modifications. A metal flue needs to be entered inside the existing chimney, filling the
space between the metal flue and the chimney 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.
Construction of new chimneys must be based on an approved design, as required by the relevant standards
in force.
In any case, the chimney must feature good draught, equal to at least 2 mm WC of negative pressure at the
base when cold. Chimneys with insufficient draught will cause the boiler to shutdown 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 pellet consumption.
A draught register should always be installed so as to maintain constant negative pressure in the chimney.
This will avoid any unwanted increases in heat output.

15
5. SY400 ELECTRONIC PANEL (CODE PEL0100DUO)
Key:
1. Main switch
2. Safety thermostat
3. Display keypad
5.1. Display
The figure below shows the control unit operator panel, with the key to the functions of each component:

16
5.2. Electronic board (inside the panel)

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5.3. Probe connections
For correct boiler operation the water temperature probes and safety thermostat sensor must be positioned
correctly. The control unit comes pre-wired with the outlet probe S4 - 3 m of cable (terminals 47, 48 page 15),
the return probe S5 - 3 m of cable (terminals 45, 46 page 15) and the safety thermostat (terminals 63, 64
page15).
These must be positioned as shown in the following figure:
5.4. Flue gas probe connection
The flue
g
as probe is alread
y
wired on the
electronic board to terminals 31 – 32, as shown
in the figure on page 15.
This must be fitted at the rear of the boiler:
near the chimne
y
attachment is a socket fo
r
inserting the probe.

18
5.5. Terminal block wiring connections
KEY:
PI Central heating system pump
PR Recirculating pump (anti-condensation)
PB DHW storage cylinder or buffer tank/combi
buffer tank pump
PPS Solar panel pump
TA Room thermostat
MP Door micro switch
VD Selector valve
NOTE:
Contacts 16 and 17
(
TA
)
are jumpered to allo
w
continuous operation of the s
y
stem pump if the room
thermostat is not connected.
WARNING:
If a room thermostat is connected, remove the jumpe
r
and make sure the two connectors are attached to the
device. Failure of the s
y
stem pump to operate ma
y
be
due to incorrect wirin
g
to the device or the device itsel
f
bein
g
fault
y
. Make sure that the room thermostat
connection has a voltage-free contact.
The door micro switch is alread
y
fitted on the support;
simply connect the two wires to terminals 18 and 19.

19
6. COMMISSIONING AND OPERATION
Before starting the boiler, check that:
a) the system is full of water and vented
b) any on-off devices are open and that the pumps are not blocked; moreover:
− Before performing any maintenance always disconnect power to the boiler and wait for the appliance to
reach room temperature.
− Never drain the water from the system unless absolutely unavoidable.
− Periodically check operation of the flue gas exhaust device and/or flue.
− Do not use flammable substances (petrol, alcohol, solvents, etc.) to clean the boiler.
Warning: for models with separate fuel containers, where the fuel is supplied by a hopper, when starting the
first time the screw must be completely filled with fuel.
6.1. Boiler in standby
When the boiler is at rest the fan is off and the top
display shows the time.
The bottom right display always shows the outlet
temperature.
6.2. Boiler ignition
Press button 7 for around 5 seconds to start the
ignition cycle.
When the operating cycle starts the top display shows “CHEC” and the fan operates at maximum speed to
vent the pellet burner draught tube. This stage lasts 2 minutes.
At the end of the two minutes the top display shows
“ACC”.
This stage involves pre-heating by the ignition heater, as indicated by a point on the bottom left display. It
lasts 2 minutes and the fan switches to minimum speed.
Once the pre-heating stage has ended the control
unit activates the screw motor to pre-load pellets into
the burner and ignite the flame. When the screw is
operating, the bottom left display shows a clockwise
movement.

20
Ignition time may vary due to the different types of pellets available on the market (the maximum duration
allowed for each attempt is set at 10 minutes).
6.3. Flame stabilisation
Once the flame has ignited the flame stabilisation
stage begins (fixed duration 3 minutes) and the top
display shows “STB”.
In this stage the heater is off, the fan operates at maximum speed and the screw motor starts running to load
pellets into the burner, based on the parameters set on the electronic board.
6.4. Normal operation
Once the stabilisation stage has ended normal
operation begins and the top display shows “ NOR “,
indicating normal boiler output; in this stage the fan
operates at maximum speed.
6.5. Boiler temperature setting
To set the boiler operating temperature use buttons
5 and 6. The bottom display will show the set
temperature.
WARNING: the operating temperature setting must
be within a minimum and maximum value, i.e.
cannot be below 65°C nor exceed 80°C.
6.6. Modulation
On reaching the set temperature and more precisely
5°C below the operating temperature, the top display
will show the text “ MOD “ indicating modulating
operation; in this stage the fan operates at minimum
speed. This message may also be shown when the
boiler starts modulating operation due to excessive
flue gas temperature (maximum setting 190°C).
6.7. Maintenance
Once time the set temperature has been reached the
top display will show “ MAN “, indicating the
temperature maintenance stage; in this stage the
boiler starts the cycle to extinguish the flame by
stopping the screw motor. Once the flue gas
temperature falls below 120°C and flame brightness
falls below the value 15 the fan starts a post-
ventilation cycle lasting 2 minutes and then stops.
When the temperature falls 5°C below the set value
the boiler will start again, repeating the ignition cycle.