DOMUSA TEKNIK BioClass iC 66 User manual

Bioclass iC 66
Biomass boiler
EN | INSTALLATION AND OPERATING INSTRUCTIONS

Thank you for choosing a DOMUSA TEKNIK heating boiler. Within the
product range offered by DOMUSA TEKNIK you have chosen BioClass iC
66 model. With a suitable hydraulic installation and with a correct fuel, this
boiler will provide the ideal level of comfort for your home.
This manual forms an essential part of the product and it must be given to
the user. We recommend you read the warnings and recommendations in
the manual carefully, as they contain important information on the safety,
use and maintenance of the installation.
These boilers must be installed by qualified personnel only, in accordance
with the legislation in force and following the manufacturer’s instructions.
Commissioning of these boilers and any maintenance operations must only
be carried out by DOMUSA TEKNIK’s Authorised Technical Assistance
Services.
Incorrect installation of these boilers could result in damage to people,
animals or property, and the manufacturer will hold no liability in such cases.
DOMUSA TEKNIK informs all parties concerned that, in compliance with
section 1 of the first additional provision of Law 11/1997, the responsibility
for delivering packaging waste or used packaging for its proper
environmental management will be that of the final owner of the product. At
the end of its useful life, the product must be taken to a selected collection
point for electrical and electronic equipment or must be returned to the
distributor at the time of purchasing a new equivalent appliance. For more
detailed information on the collection schemes available, contact either the
collection facilities of the local authority or the distributor where the purchase
was made

EN
4
BIOCLASS iC 66
ÍNDICE
1 LIST OF COMPONENTS ............................................................................................................... 6
2 INSTALLATIONS INSTRUCTIONS ................................................................................................ 8
2.1 LOCATION .............................................................................................................................................. 8
2.2 HYDRAULIC INSTALLATION .......................................................................................................................... 9
2.3 INSTALLING A SANIT HOT WATER TANK (OPTIONAL) .......................................................................................... 9
2.4 FUEL .................................................................................................................................................. 10
2.5 INSTALLING THE HOPPER .......................................................................................................................... 11
2.6 INSTALLATION OF A ROOM TEMPERATURE SENSOR OR THERMOSTAT ...................................................................... 12
2.7 ELECTRICAL CONNECTION ........................................................................................................................ 13
2.8 COMBUSTION PRODUCT REMOVAL ............................................................................................................... 13
2.9 PRESSURE DROP CURVES .......................................................................................................................... 14
2.10 INSTALLATION WITH A BT BUFFER TANK (OPTIONAL) .................................................................................... 14
2.11 INSTALLATION WITH A BT-DUO BUFFER TANK (OPTIONAL) ............................................................................. 19
3 COMMISSIONING OF THE BOILER ............................................................................................ 21
3.1 PRIOR WARNINGS .................................................................................................................................. 21
3.2 FILLING THE INSTALLATION ....................................................................................................................... 21
3.3 INITIAL CALIBRATION OF THE FEED AUGER .................................................................................................... 21
3.4 COMMISSIONING ................................................................................................................................... 21
3.5 INSTALLATION DELIVERY .......................................................................................................................... 22
4 DIGITAL DISPLAY .................................................................................................................... 23
5 OPERATION ............................................................................................................................. 26
5.1 “ONLY HEATING” OPERATION .................................................................................................................... 26
5.2 OPERATING WITH A SANIT DHW TANK (OPTION) ........................................................................................... 26
5.3 BOILER TEMPERATURE SET POINT SELECTION ................................................................................................. 27
5.4 DHW TEMPERATURE SET POINT SELECTION (WITH DHW TANK INSTALLED ONLY) .................................................... 27
5.5 SELECTING THE SET POINT TEMPERATURE OF THE BUFFER TANK (ONLY WITH BUFFER TANK) ........................................ 28
6 OPERATION WITH A BT BUFFER TANK (OPTIONAL) .................................................................. 29
6.1 OPERATION WITH A TEMPERATURE SENSOR IN THE BT BUFFER TANK (P.08 = 1 OR 2) .............................................. 29
6.2 OPERATION WITH A CONTROL THERMOSTAT IN THE BT BUFFER TANK (P.08 = 3 OR 4) ............................................. 30
7 OPERATION WITH A BT-DUO BUFFER TANK (OPTIONAL) .......................................................... 31
8 "
ICONNECT " CONNECTIVITY .................................................................................................... 32
8.1 REQUIREMENTS FOR CONNECTING TO ICONNECT ............................................................................................. 32
8.2 BOILER REGISTRATION IN ICONNECT ........................................................................................................... 33
8.3 DESCRIPTION OF THE ICONNECT APPLICATION ............................................................................................... 34
8.4 ICONNECT APP MAP ............................................................................................................................... 34
9 OPERATING WITH LAGO FB OT+ REMOTE CONTROL (OPTIONAL) ............................................. 36
10 USER MENU ........................................................................................................................... 37
10.1 ASHTRAY STATUS ................................................................................................................................. 39
11 SETUP MENU ......................................................................................................................... 40
11.1 TIMERS PROGRAMMING PROCESS .............................................................................................................. 41
11.2 HEATING TIME SCHEDULES ...................................................................................................................... 43
11.3 BOILER TIMER PROGRAMMING .................................................................................................................. 43
11.4 PROGRAMMING THE FUEL SUCTION SYSTEM ................................................................................................. 43
11.5 DHW RECIRCULATION FUNCTION TIMER PROGRAMMING (DHW TANK OPTION ONLY) ............................................... 43
11.6 TIME SETTING ..................................................................................................................................... 44
11.7 EMPTY ASH BOX NOTICE ......................................................................................................................... 44
11.8 MANUAL SETTING OF FEED AUGER CALIBRATION ............................................................................................ 45
11.9 REGISTRATION OF THE BOILER IN ICONNECT ................................................................................................ 45
11.10 SCREEN CONTRAST SETTING .................................................................................................................. 45
12 CALIBRATION MENU .............................................................................................................. 46
12.1 FEED AUGER FILLING ............................................................................................................................. 4 7
12.2 FEED AUGER CALIBRATION ...................................................................................................................... 48
12.3 MANUAL SETTING OF FEED AUGER CALIBRATION ............................................................................................ 49
12.4 MANUAL ASH CLEANING ACTIVATION .......................................................................................................... 49
12.5 MANUAL CIRCULATION PUMPS ACTIVATION .................................................................................................. 49

5
BIOCLASS iC 66
13 TECHNICAL MENU .................................................................................................................. 50
13.1 ENTRY AND SET THE ACCESS CODE ("COD", P.25) ......................................................................................... 54
14 BOILER'S SETUP PARAMETERS ............................................................................................... 55
14.1 BOILER MODEL (P.01) .......................................................................................................................... 55
14.2 BOILER HEAT OUTPUT (P.02, P.03) .......................................................................................................... 55
14.3 GENERAL FAN SPEED FACTOR (P.04) ......................................................................................................... 55
14.4 FUEL FOR IGNITION (P.05) ..................................................................................................................... 55
14.5 FUEL CONSUMPTION (P.06) .................................................................................................................... 55
14.6 MANAGING BT AND BT-DUO BUFFER TANKS (P.08, P.28, P.50) ..................................................................... 56
14.7 AUXILIARY PARAMETER FOR FUEL SELECTION (P.26) ...................................................................................... 56
14.8 BOILER MINIMUM TEMPERATURE MODE (P.13, P.14) ..................................................................................... 56
15 HEATING CIRCUIT'S SETUP PARAMETERS ............................................................................... 57
15.1 HEATING PUMP POST-CIRCULATION TIME (P.15) ........................................................................................... 57
15.2 BOILER'S PUMP OPERATING MODE (P.18) ................................................................................................... 57
15.3 MINIMUM BOILER WATER PRESSURE (P.19) ................................................................................................. 57
15.4 TYPE OF ROOM TEMPERATURE DEVICE (P.46, P.47, P.48) .............................................................................. 57
15.5 ROOM TEMPERATURE HYSTERESIS (P.49) ................................................................................................... 58
15.6 ROOM TEMPERATURE CORRECTION (P.51, P.52, P.53) .................................................................................. 58
16 DHW CIRCUIT'S SETUP PARAMETERS ..................................................................................... 59
16.1 DHW INSTALLATION MODE (P.09) ........................................................................................................... 59
16.2 DHW PUMP POST-CIRCULATION TIME (P.16) .............................................................................................. 59
16.3 LEGIONELLA PROTECTION FUNCTION (P.17) ................................................................................................ 59
16.4 DHW RE-CIRCULATION FUNCTION (P.20 = 2) ............................................................................................. 59
17 ADDITIONAL FUNCTIONS ....................................................................................................... 60
17.1 TIME OF THE FUEL SUCTION SYSTEM CYCLE (P.22) ........................................................................................ 60
17.2 RESET DEFAULT VALUES (P.24) ............................................................................................................... 60
17.3 PUMPS ANTI-LOCK FUNCTION ................................................................................................................... 60
17.4 ANTI-FROST FUNCTION .......................................................................................................................... 60
17.5 BOILER PRESSURE SENSOR FUNCTION ......................................................................................................... 60
17.6 CONNECTING THE LAGO FB OT+ REMOTE CONTROL ..................................................................................... 60
17.7 ROOM THERMOSTAT CONNECTION ............................................................................................................. 61
17.8 CONNECTING THE ROOM SENSOR .............................................................................................................. 61
18 MULTI-FUNCTIONAL RELAY (P.20) .......................................................................................... 62
18.1 BOILER ALARMS EXTERNAL SIGNAL (P.20 = 1) ............................................................................................. 62
18.2 DHW RE-CIRCULATION FUNCTION (P.20 = 2) ............................................................................................. 62
18.3 AUTOMATIC WATER FILLING FUNCTION (P.20 = 3) ....................................................................................... 62
19 SAFETY LOCK-OUTS ............................................................................................................... 63
19.1 TEMPERATURE SAFETY LOCK .................................................................................................................... 63
19.2 FUEL ENTRANCE TUBE OVERHEAT SAFETY CUT-OUT ........................................................................................ 64
19.3 LOW PRESSURE LOCK-OUT ...................................................................................................................... 64
20 SHUTTING DOWN THE BOILER ............................................................................................... 64
21 EMPTYING THE BOILER .......................................................................................................... 64
22 BOILER MAINTENANCE ........................................................................................................... 65
22.1 FREQUENCY OF MAINTENANCE OF THE BOILER AND CHIMNEY ............................................................................. 65
22.2 BURNER CLEANING PROCEDURE ................................................................................................................ 65
22.3 HEAT EXCHANGER CLEANING PROCEDURE .................................................................................................... 67
22.4 DRAINING THE CONDENSATE WATER .......................................................................................................... 68
22.5 BOILER WATER CHARACTERISTICS ............................................................................................................. 68
23 DIAGRAMS AND MEASUREMENTS ........................................................................................... 69
24 CONNECTIONS DIAGRAM ....................................................................................................... 70
24.1 BOILER ............................................................................................................................................. 70
24.2 BURNER ............................................................................................................................................ 71
24.3 ELECTRICAL DIAGRAM ............................................................................................................................ 72
25 TECHNICAL DATA .................................................................................................................. 73
26 ALARM CODES ....................................................................................................................... 75

EN
6
BIOCLASS iC 66
1 LIST OF COMPONENTS
1 2 3 4
5
6
7
8
9
11
10
12
13
1. Feed auger.
2. Sensor housing.
3. Automatic Air vent.
4. Fan.
5. Heat exchanger cleaning system.
6. Water pressure sensor.
7. Fuel entrance safety thermostat.
8. Boiler body.
9. Ash drawer.
10. Air pressure sensor.
11. Burner.
12. Peephole.
13. External ash box.

7
BIOCLASS iC 66
CONTROL COMPONENTS
17 1820
16
19
1514
14. MENU touch button:
This button is used to access and browse through
the "User Menu".
15. Digital display:
It is the main boiler functioning display, on which
all the operating information, settings and values
appear. This display is also used to access the
appliance's user and service settings. In standard
operating mode (default display), the actual
boiler temperature is shown. If malfunction
occurs, an alarm code will appear on the digital
display instead of the temperature.
16. RESET touch button:
This button is used to restore functioning of the
boiler after a lock-out situation. Also it is used to
exit from any of the menus or parameters of the
boiler without saving it and to return to the
previous menu level.
17. ON touch button:
This button switches on and off the boiler.
18. Boiler temperature touch button:
This button is used to select the boiler set point
temperature. It is also used to disable the hot
water function.
19. DHW temperature touch button:
This button is used to select the desired domestic
hot water set point temperature (only if a DHW
tank is connected to the boiler). It is also used to
disable the DHW function.
20. SET touch button:
This button is used to access and browse through
the "Setup menu". Touch this button to access
the settings options.

EN
8
BIOCLASS iC 66
2 INSTALLATIONS INSTRUCTIONS
The boiler must be installed by personnel authorised by the Ministry of Industry, in compliance with the
applicable laws and regulations.
This boiler is suitable for heating water to a temperature below boiling point at atmospheric pressure. It
must be connected to a heating installation and/or a domestic hot water distribution network, which must
always be compatible with its performance and power.
This appliance must only be used for the purpose for which it has been expressly designed. Any other use
is considered unsuitable and therefore hazardous. The manufacturer shall not be considered liable under
any circumstances for damage caused by unsuitable, erroneous or irrational use.
Remove all the packaging and check the contents are complete. In case of doubt, do not use the boiler.
Contact your supplier. Keep the packaging elements out of reach of children, as they can be dangerous.
Be aware that the base of the boiler is fixed to the wooden pallet with four screws.
When you no longer wish to use the boiler, disable the parts that could be a potential source of hazard.
2.1 Location
The boiler must be installed in a sufficiently ventilated site, away from humidity. It must be located so
that the air grilles on the premises are not obstructed and normal boiler maintenance is possible even
if it is placed between items of furniture. One metre of free space must be left above the boiler for this
purpose.
If you want to connect the boiler with the iConnect Internet platform or register it in the iConnect
user application, it will also be essential to have coverage of the home's Wi-Fi network in the place
where the boiler is located.
You must maintain the minimum distances to the surrounding components:
a
b
c
d
e
a = mín. 500 mm.
b = mín. 500 mm.
c = mín. 1000 mm.
d = mín. 500 mm.
e = mín. 2500 mm.

9
BIOCLASS iC 66
2.2 Hydraulic installation
The hydraulic installation must be made by qualified personnel. The applicable installation legislation is
to be complied with, and the following recommendations should also be taken into account:
• It is essential to install the external circulation kit (back in protection Kit) with the boiler,
to prevent any water condensation in the heat exchanger. If this requirement is not complied
with, DOMUSA TEKNIK’s guarantee of the appliance will automatically be null and void.
• The inside of the installation piping should be thoroughly cleaned before switching on the
boiler.
• We recommend inserting cut-off valves between the installation piping and the boiler to
simplify maintenance tasks.
• Leave a free space around the boiler for carrying out any maintenance and repair operations.
• Drain valves and suitable devices for correctly bleeding the air from the circuit during the
boiler filling stage should be fitted.
• Install all the necessary safety elements (expansion vessel, safety valve, etc.) to comply with
the applicable regulations for the installation.
• If the boiler is installed at a lower height than the heating installation, it is recommendable
to create a siphon at the boiler outlet, to prevent the installation from heating up due to
natural convection when heating is not required.
2.3 Installing a Sanit hot water tank (Optional)
For a correct electrical connection of a Sanit DHW hot water tank with BioClass iC 66 boiler, these
steps should be followed:
• Unplug the boiler from the mains power.
• Connect a DHW temperature sensor (supplied optionally) to the sensor terminal strip J7 (Sa;
terminals 16 and 17)
(see "Connections Diagram") .
• Insert the temperature sensor bulb in the bulb-holder sheath provided on the hot water tank.
• Connect the 3-way DHW diverter valve or the hot water tank booster pump (depending on
the installation, modify parameter P.09) to the supply terminal strip J3 (BA; terminals 6 and
N)
(see "Connections Diagram") .
• Connect the boiler pump to the supply terminal strip J3 (BC; terminals 5 and N)
(see
"Connections Diagram")
.

EN
10
BIOCLASS iC 66
The hydraulic installation for the 3-way DHW diverter valve should be made so that the heating circuit
can flow through the valve when it is in rest position (not energised):
HEATING
BOILER
D.H.W.
NC
V
3V (BA)
OPTIÓN WITH V3V (P.09 = 0)
HEATING (BC)
BOILER
OPTIÓN WITH 2 PUMP CIRCULATION(P.09 = 1)
D.H.W. (BA)
(BA)
NO
For correct hydraulic installation of the hot water tank, carefully follow the assembly and connection
instructions enclosed with the same.
When the hot water tank is installed next to a buffer tank, see
"Installing a BT Buffer tank (Optional)"
in this manual to select the appropriate parameters.
2.4 Fuel
BioClass iC 66 boiler must be fuelled by EN Plus-A1 or DIN PLUS certified wood pellet. The DIN
PLUS or EN Plus-A1certificate assures that the fuel’s humidity levels and calorific value are ideal for
optimum boiler functioning. If this requirement is not complied with, DOMUSA TEKNIK’s guarantee
of the appliance will automatically be null and void.
The following aspects must be taken into account for the correct storage of fuel:
• Wood pellets should be stored in a room protected from humidity and weather. It is important
to create an air gap around the wood pellet bags to ensure good ventilation. These bags
should never be stored directly in contact with the ground and / or a wall.
• Wood pellets must be handled with care, as mixing them in bags can damage them.
• Wood pellets must be visually inspected before use in the boiler, to ensure the absence of
dust or pellets crushed in large quantities, which could cause a boiler malfunction.

11
BIOCLASS iC 66
2.5 Installing the hopper
DOMUSA TEKNIK supplies a reserve tank with the boiler with a Fuel suction system for the transport
and storage of pellets. It is also equipped with adjustable feet for height regulation. In addition, the
tank incorporates an adjustable leg system to adjust its height.
IMPORTANT: Ensure the height of the elliptical holes on the sides of the boiler and on
the hopper coincide, for correct insertion of the feed auger. To do this,
make the necessary adjustments for height (using the adjustment feet)
and depth (correctly positioning the hopper).

EN
12
BIOCLASS iC 66
2.6 Installation of a room temperature sensor or thermostat
The BioClass iC 66 boiler has a TA1 (J6) terminal strip (see "Connection Diagrams") ,prepared for the
connection of a device to measure the temperature conditions inside the house, which will the manage
the remote control of the heating circuit.
These devices will need to be suitably located within the home to be able to correctly manage the
comfort of the house. It is advisable to install them in an area of the home that has regular use (living
room, master bedroom, or similar), if possible avoiding rooms where heat or cold could be generated,
such as kitchens, bathrooms, refrigerated larders, etc. In turn, they must be installed at a medium
height and as far as possible from any source of heat or cold that could distort the temperature reading,
such as windows, fireplaces, stoves, etc.
Two different types of devices can be connected to the BioClass iC 66 boiler:
Room sensor
The room sensor measures the temperature inside the home and transmits it to the boiler which
displays it on the screen. The user will be able to select the desired setpoint temperature at any time
from the "User" menu, and will have the possibility of adjusting the desired comfort times for the
installation from the "Heating time programming"
(see "Configuration Menu") . The electronic control of
the boiler will manage the operating conditions to achieve the desired comfort and will modulate the
boiler temperature to optimise the operation and efficiency of the heating installation.
For the correct connection of a room sensor to the BioClass iC 66 boiler, proceed as follows:
• Unplug the boiler from the mains.
• Connect the room sensor, supplied with the boiler, to the TA1 (J6) terminal strip (see
"Connection Diagrams"). The bridge that connects the terminals of said strip must be
removed first.
• Reconnect the boiler to the mains power.
• The boiler comes factory configured for the connection of a "Room Sensor". If for any reason
this is not the case, for its correct configuration, parameter P.46 must be set to 1 (see
"Technical Menu").
• The electronic control allows correcting the value measured by the room temperature sensor,
using parameter P.51. To make this adjustment correctly, first of all it should be waited a
minimum of 10 minutes for the measured value to stabilize (without touching the room
temperature sensor).
Room thermostat
A room thermostat connected to the boiler will activate and deactivate the heating demand depending
on its setting. In addition, if it has a time programming (chronothermostat), the user can set the desired
heating operating periods.
For the correct connection of a thermostat to the BioClass iC 66 boiler, proceed as follows:
• Unplug the boiler from the mains.
• Connect the room thermostat to the terminal block TA1 (J6) (see "Connection Diagrams"),
having previously removed the bridge that connects the terminals of said strip.
• Reconnect the boiler to the mains power.
• Lastly, the boiler must be configured to operate with "Room Thermostat", setting parameter
P.46 to 0 (see "Technical Menu").

13
BIOCLASS iC 66
2.7 Electrical Connection
The boiler is equipped for connection at 230 V~ 50 Hz. The socket should have an appropriate
earth connection.
The terminal strip J2 includes terminals for connecting the feed auger, whereas the terminal strip J3
includes terminals for connecting the circulation pump of the boiler (BC) and the 3-way diverter valve
(or circulation pump) for the optional DHW circuit. The terminal strip J7 includes terminals for
connecting a sensor for the optional DHW circuit. This sensor must be supplied by DOMUSA TEKNIK.
IMPORTANT: Before carrying out any work on the boiler's electrical installation, always
ensure it is disconnected from the mains.
2.8 Combustion product removal
BioClass iC 66 boiler is a biomass boiler and it is essential for it to be connected to a flue, i.e. a smoke
duct able to create a pressure drop (which in this case should be between 0.10 and 0.20 mbar), in
compliance with the applicable laws to this regard.
The combustion product exhaustion ducts must be installed by qualified personnel and must comply
with the regulations in force. For the flue to create a pressure drop, the following recommendations
should be taken into account:
• It should be suitably insulated.
• It should be independently located, with a separate flue for each boiler.
• It should be vertical, avoiding any angles greater than 45º.
• It should always have the same diameter. It is recommendable for it to be circular, and never
any narrower than the boiler outlet.
• It is obligatory to install a fume inspection plate with condensation collection, to
remove the condensation generated in the flue. Otherwise, the condensation may
reach the inside of the boiler and cause irreparable damage, which would not be covered
by DOMUSA TEKNIK’s guarantee. The condensation pipe should lead to a drain outlet,
as a large amount of water may be generated. This connection must be made in compliance
with the regulations for draining off condensation water to the drain network.
• It is recommended to install a draught stabiliser to prevent any pressure drop
variations in the flue due to atmospheric conditions, which could affect correct boiler
combustion. This draught stabiliser must be installed below the fume inspection plate to
prevent any leakage of combustion gases.

EN
14
BIOCLASS iC 66
2.9 Pressure drop curves
For the appropriate sizing of the hydraulic installation, as well as the pump operation curves, the
pressure loss caused by the boiler and the thermostatic mixing valve should be taken into account. The
following graph shows the pressure loss curves for the boiler and for the boiler with the thermostatic
valve (anti-condensation):
2.10 Installation with a BT Buffer Tank (Optional)
The BioClass iC 66 boiler can be accompanied by a BT Buffer Tank during the installation from the
wide range offered by DOMUSA TEKNIK, which may increase the benefits provided by the boiler in the
heating service.
For this reason, the electronic control of the boiler is equipped with an input for a temperature sensor
or a temperature thermostat (Sbt; terminals 18-19 on connection strip J7) and a circulation pump
output (Bbt; terminals N-7 on the connection strip J2) dedicated exclusively to managing the heating
of the buffer tank. Using these control elements of the boiler you will be able to manage 4 different
modes of buffer tank hydraulic installation. The installation type will be selected using parameter P.08
in the "Technician" menu on the control panel.
The boiler is supplied with this installation option disabled. To enable it, the electrical resistance (Rbt)
connected between terminals 18 and 19 of connection strip J7 (see "Connection Diagram") must be
disconnected and replaced with a temperature sensor (supplied as an option by DOMUSA TEKNIK)
or a control thermostat installed in the BT buffer tank. After disconnecting the resistance in the
"Technician" menu of the control panel, parameter P.08 must be enabled, via which you can select the
installation mode desired.
The following sections describe in detail the hydraulic and electrical connection characteristics for each
installation mode.

15
BIOCLASS iC 66
2.10.1 Installation with Sanit DHW tank after BT tank and control by temperature
sensor (P.08 = 1)
In this installation mode, all heating circuits, as well as the circuit for producing DHW by accumulation,
if present, must be hydraulically connected to the BT buffer tank. In other words, as shown in the
following hydraulic diagram, the BT buffer tank is connected to the boiler, interposing a circulation
pump (Bbt), and all the heating circuits of the system are connected to the BT tank. The temperature
of the BT tank is controlled and managed by a temperature sensor (Sbt) immersed in the buffer tank
and electrically connected to the boiler. The temperature sensor is optionally supplied by DOMUSA
TEKNIK.
Heating
installation
+ DHW
After the hydraulic installation of all the system components, proceed as follows to carry out the correct
electrical connection of the BT buffer tank to the BioClass iC 66 boiler:
• Unplug the boiler from the mains power.
• Disconnect the electrical resistance (Rbt) connected between terminals 18 and 19 of
connection strip J7
(see "Connection Diagram") .
• Connect the BT tank temperature sensor (supplied optionally) to the sensor connection strip
J7 (Sbt; terminals 18 and 19)
(see "Connection Diagram") .
• Insert the temperature sensor bulb in the bulb-holder sheath provided in the buffer tank.
• Connect the BT tank feed pump to the component connection strip J2 (Bbt; terminals N and
7)
(see "Connection Diagram").
• Connect the boiler to the mains power.
• Using the control panel, access parameter P.08 in the "Technician" menu
(see "Technician
Menu")
and set the value to "1".
• After that, if it is necessary, set also the parameter P.28 "BT buffer tank temperature
hysteresis".
Once the hydraulic and electrical connection described above has been completed, to adjust and
configure the BT buffer tank operation, carefully read the section "
Operation with a BT buffer tank " in
this manual.

EN
16
BIOCLASS iC 66
2.10.2 Installation with Sanit DHW tank before BT tank and control by temperature
sensor (P.08 = 2)
In this installation mode, all heating circuits must be hydraulically connected to the BT buffer tank,
and the circuit for producing DHW by accumulation should be hydraulically connected to the boiler,
upstream from the BT buffer tank. In other words, the BT buffer tank and the Sanit DHW tank, if
present, are connected in parallel to the boiler. The DHW diverter valve and the BT tank feed pump
(Bbt) must be installed as indicated in the following hydraulic diagrams. The temperature of the BT
tank is controlled and managed by a temperature sensor (Sbt) immersed in the buffer tank and
electrically connected to the boiler. The temperature sensor is optionally supplied by DOMUSA TEKNIK.
Heating
installation
DHW diverter valve
After the hydraulic installation of all the system components, proceed as follows to carry out the correct
electrical connection of the BT buffer tank to the BioClass iC 66 boiler:
• Unplug the boiler from the mains power.
• Disconnect the electrical resistance (Rbt) connected between terminals 18 and 19 of
connection strip J7
(see "Connection Diagram").
• Connect the BT tank temperature sensor (supplied optionally) to the sensor connection strip
J7 (Sbt; terminals 18 and 19)
(see "Connection Diagram") .
• Insert the temperature sensor bulb in the bulb-holder sheath provided in the buffer tank.
• Connect the BT tank feed pump to the component connection strip J2 (Bbt; terminals N and
7)
(see "Connection Diagram") .
• Connect the boiler to the mains power.
• Using the control panel, access parameter P.08 in the "Technician" menu
(see "Technician
Menu")
and set the value to "2".
• After that, if it is necessary, set also the parameter P.28 "BT buffer tank temperature
hysteresis".
For the correct hydraulic and electrical installation of a Sanit DHW tank with a BioClass iC 66 boiler,
carefully follow the directions in the section
"Installing a Sanit tank" in this manual.
Once the hydraulic and electrical connection described above has been completed, to adjust and
configure the BT buffer tank operation, carefully read the section
"Operation with a BT buffer tank" in
this manual.

17
BIOCLASS iC 66
2.10.3 Installation with Sanit DHW tank before BT tank and control by temperature
(P.08 = 3)
In this installation mode, all heating circuits, as well as the circuit for producing DHW by accumulation,
if present, must be hydraulically connected to the BT buffer tank. In other words, as shown in the
following hydraulic diagram, the BT buffer tank is connected to the boiler, interposing a circulation
pump (Bbt), and all the heating circuits of the system are connected to the BT tank. The temperature
of the BT tank is controlled and managed by a thermostat (Tbt) installed and immersed in the buffer
tank and electrically connected to the boiler. The temperature control thermostat is not supplied by
DOMUSA TEKNIK but can be purchased at any specialist central heating supplies warehouse.
Heatin
g
installation
+ DHW
After the hydraulic installation of all the system components, proceed as follows to carry out the correct
electrical connection of the BT buffer tank to the BioClass iC 66 boiler:
• Unplug the boiler from the mains power.
• Disconnect the electrical resistance (Rbt) connected between terminals 18 and 19 of
connection strip J7
(see "Connection Diagram") .
• Connect the NC contact (normally closed) on the BT tank control thermostat on the sensor
connection strip J7 (Sbt; terminals 18 and 19)
(see "Connection Diagram").
• Insert the thermostat bulb into the bulb-holder sheath provided in the buffer tank.
• Connect the BT tank feed pump to the component connection strip J2 (Bbt; terminals N and
7)
(see "Connection Diagram") .
• Connect the boiler to the mains power.
• Using the control panel, access parameter P.08 in the "Technician" menu
(see "Technician
Menu")
and set the value to "3".
Once the hydraulic and electrical connection described above has been completed, to adjust and
configure the BT buffer tank operation, carefully read the section
"Operation with a BT buffer tank" in
this manual.

EN
18
BIOCLASS iC 66
2.10.4 Installation with Sanit DHW tank before BT tank and control by thermostat
(P.08 = 4)
In this installation mode, all heating circuits must be hydraulically connected to the BT buffer tank, and
the circuit for producing DHW by accumulation should be hydraulically connected to the boiler,
upstream from the BT buffer tank. In other words, the BT buffer tank and the Sanit DHW tank, if
present, are connected in parallel to the boiler. The DHW diverter valve and the BT tank feed pump
(Bbt) must be installed as indicated in the following hydraulic diagrams. The temperature of the BT
tank is controlled and managed by a thermostat (Tbt) installed and immersed in the buffer tank and
electrically connected to the boiler. The temperature control thermostat is not supplied by DOMUSA
TEKNIK but can be purchased at any specialist central heating supplies warehouse.
Heating
installation
DHW diverter valve
After the hydraulic installation of all the system components, proceed as follows to carry out the correct
electrical connection of the BT buffer tank to the BioClass iC 66 boiler:
• Unplug the boiler from the mains power.
• Disconnect the electrical resistance (Rbt) connected between terminals 18 and 19 of
connection strip J7
(see "Connection Diagram").
• Connect the NC contact (normally closed) on the BT tank control thermostat on the sensor
connection strip J7 (Sbt; terminals 18 and 19)
(see "Connection Diagram").
• Insert the thermostat bulb into the bulb-holder sheath provided in the buffer tank.
• Connect the BT tank feed pump to the component connection strip J2 (Bbt; terminals N and
7)
(see "Connection Diagram").
• Connect the boiler to the mains power.
• Using the control panel, access parameter P.08 in the "Technician" menu
(see "Technician
Menu")
and set the value to "4".
For the correct hydraulic and electrical installation of a Sanit DHW tank with a BioClass iC 66 boiler,
carefully follow the directions in the section
"Installing a Sanit tank" in this manual.
Once the hydraulic and electrical connection described above has been completed, to adjust and
configure the BT buffer tank operation, carefully read the section
"Operation with a BT buffer tank" in
this manual.

19
BIOCLASS iC 66
2.11 Installation with a BT-DUO buffer tank (Optional)
The BioClass iC 66 boiler can be accompanied by a BT-DUO Buffer Tank during the installation
from the wide range offered by DOMUSA TEKNIK, which may increase the benefits provided by the
boiler in the heating service. This tank has a hot water storage tank inside, thereby adding the provision
of DHW in addition to the buffer tank functionality. For this reason, its connection to the boiler as well
as its operating configuration are specific.
For this reason the electronic control of the boiler is equipped with an input for connecting the primary
control thermostat Tcp of the BT-DUO tank (input Sbt; terminals 18-19 on connection strip J7) and
a circulation pump output (Bbt; terminals N-7 on the connection strip J2) dedicated exclusively to
managing the heating of the buffer tank. Also, for correctly managing the DHW production in the tank
integrated in the BT-DUO tank, a DHW temperature sensor (supplied optionally) must be included in
the installation.
The boiler is supplied with this installation option disabled. To enable it, the electrical resistance (Rbt)
connected between terminals 18 and 19 of connection strip J7
(see "Connection Diagram") must be
disconnected and replaced with a temperature sensor (supplied as an option by DOMUSA TEKNIK) or
a control thermostat installed in the BT buffer tank. After disconnecting the resistance in the
"Technician" menu of the control panel, parameter P.08 must be enabled, via which you can select the
installation mode and appropriate functioning for this type of buffer tank.
The BT-DUO buffer tank is hydraulically connected to the boiler, interposing a circulation pump (Bbt),
and all the central heating circuits of the system are connected to the BT-DUO tank. For the correct
hydraulic installation of the BT-DUO tank and the feed pump Bbt, carefully follow the instructions in
the following hydraulic diagram:
Heating
Installation

EN
20
BIOCLASS iC 66
After the hydraulic installation of all the system components, proceed as follows to carry out the correct
electrical connection of the BT-DUO buffer tank to the BioClass iC 66 boiler:
• Unplug the boiler from the mains power.
• Disconnect the electrical resistance (Rbt) connected between terminals 18 and 19 of
connection strip J7
(see "Connection Diagram") .
• Using a 2-wire electrical hose connect the TAcald terminals (terminals 7 and 8 in the wiring
diagram of the BT-DUO tank manual) of the BT-DUO tank control thermostat (Tcp) to the
sensor connection strip J7 (Sbt; terminals 18 and 19)
(see "Connection Diagram").
• Connect the DHW temperature sensor (supplied optionally) to the sensor connection strip J7
(Sa; terminals 16 and 17)
(see "Connection Diagram") , previously removing the resistance
Ra, supplied as standard with the boiler.
• Insert the DHW temperature sensor bulb into the bulb-holder sheath provided in the DHW
tank of the BT-DUO buffer tank.
• Connect the BT-DUO tank feed pump to the component connection strip J2 (Bbt; terminals
N and 7)
(see "Connection Diagram").
• Connect the boiler to the mains power.
• To correctly configure the type of installation you must adjust parameters P.08 y P.09 in
the "Technician" menu on the control panel. Access parameter P.08 in the "Technician"
menu
(see "Technician Menu") and set the value to "4". Next, access parameter P.09 from
the same menu and set the value to "0".
For the correct hydraulic and electrical installation of a BT-DUO buffer tank, carefully follow the
instructions in the manual supplied with it.
Once the hydraulic and electrical connection described above has been completed, to adjust and
configure the BT-DUO buffer tank operation, carefully read the section
"Operation with a BT-DUO
buffer tank"
in this manual.