Fondital minorca rc User manual

IST 03 C 972 - 01
MINORCA
KC - KR - KRB 24
INSTALLATION, USE AND MAINTENANCE
EN
Translation of the
original instructions (in
Italian)

2
Dear Sirs,
thank You for choosing and buying one of our products. Please read these instructions carefully in order to properly install, operate, and
maintain the product.
WARNING
• We inform users that:
• Boilers shall be installed by an authorised company under the requirements set forth by the prevailing rules, in full compliance
with the prevailing regulations and standards.
• Anyone entrusting installation to an unqualified installer will be subject to administrative sanctions.
• Boilers must be maintained by qualified personnel only, under the requirements set forth by the prevailing rules.
We hereby inform you that certain models, versions and/or accessories relevant to the products this manual refers to, might not
be available in some countries.
Therefore, it is recommended to contact the manufacturer or the importer in order to get the necessary information about the
actual availability of such models, versions and/or accessories.
The manufacturer reserves the right to modify the products and/or its components as deemed necessary, in any moment and
without prior notice.
This instruction manual is available in two languages, Italian and English, without prejudice to the prevalence of Italian language
in case of differences in translation and/or dispute on construction of the text.

3
General notes for installing and maintenance technicians, and users
This instruction manual is an integral and essential part of the product. It shall be supplied by the installer to the user who shall keep it carefully
to consult it whenever necessary.
This document shall be supplied together with the equipment in case the latter is sold or transferred to others.
DANGER
This equipment has been manufactured to be connected to a room heating system and to a DHW distribution system.
Any other use shall be considered unsuitable and dangerous for people, animals, and/or property.
The equipment shall be installed in compliance with the prevailing standards and in accordance with the manufacturer's instructions specified
in this manual: the manufacturer will not be held responsible for injuries to people and animals and/or damages to property resulting from
an incorrect installation.
Damage and/or injury caused by incorrect installation or use and/or damage and/or injury due to non-observance of the manufacturer’s
instructions shall release the manufacturer from any and all contractual and extra-contractual liability.
Before installing the boiler, check that the technical data correspond to the requirements for its correct use in the system.
Check that the boiler is intact and it has not been damaged during transport and handling. Do not install equipment which is clearly damaged
and/or faulty.
Do not obstruct the air intake openings.
Only original accessories or optional kits (including the electric ones) are to be installed.
Properly dispose of the packaging as all the materials can be recycled. The packaging must therefore be sent to specific waste management
sites.
After removing the packaging, make sure that its elements (clips, plastic bags, foam polystyrene etc.) are note left within the reach of children
as they are potential hazard sources.
In the event of failure and/or faulty functioning, switch off the boiler. Do not attempt to make repairs: contact qualified technicians.
Original parts must be used for all repairs to the boiler.
Non-observance of the above requirements may affect the safety of the boilers and endanger people, animals and/or property.
WARNING
The boiler must be serviced periodically as indicated in the relevant section of this manual.
Appropriate boiler maintenance ensures efficient operation, environment preservation, and safety for people, animals and objects.
Incorrect and irregular maintenance can be a source of danger for people, animals and property.
The user is strongly advised to have the system serviced and repaired by qualified personnel, satisfying all prevailing law requirements, and
trained to properly carry out these operations.
In the event of long periods of inactivity of the boiler, disconnect it from the electrical power mains and close the gas cock. The electronic
antifreeze function will not be operative with the device disconnected from the electric power supply and gas cock closed.
Should there be a risk of freezing, add antifreeze: it is not advisable to drain the system as this may result in damage;use specific anti-freeze
products suitable for multi-metal heating systems.

4
DANGER
With gas fired boilers, take the following measures if you smell gas:
• Do not turn on or off electric switches and do not turn on electric appliances.
• Do not ignite flames and do not smoke.
• Close the main gas cock.
• Open doors and windows.
• Contact a Service Centre, a qualified installer or the gas supply company.
Never use a flame to locate a gas leak.
The boiler is designed for installation in the countries indicated on the technical data plate: installation in any other country may
be a source of danger for people, animals and/or property.
The manufacturer will bear no contractual and tortious liability for failure to comply with all the instructions above.

5
1. Instructions for the user .......................................................... 8
1.1 Control panel....................................................................................................................................................................................... 8
1.2 Interpreting boiler status from display indications.................................................................................................................... 10
1.3 Boiler operation .................................................................................................................................................................................. 11
1.4 Boiler shut-down ................................................................................................................................................................................ 14
1.5 Maintenance ....................................................................................................................................................................................... 17
1.6 Notes for the user................................................................................................................................................................................ 17
2. Technical features and dimensions................................................. 18
2.1 Technical features .............................................................................................................................................................................. 18
2.2 Dimensions .......................................................................................................................................................................................... 20
2.3 Boiler layouts....................................................................................................................................................................................... 22
2.4 Operating data ................................................................................................................................................................................... 25
2.5 General characteristics...................................................................................................................................................................... 25
2.6 ERP and Labelling data..................................................................................................................................................................... 27
3. Instructions for the installer ....................................................... 29
3.1 Installation standards....................................................................................................................................................................... 29
3.2 Choosing where to install the boiler.............................................................................................................................................. 29
3.3 Positioning the boiler ........................................................................................................................................................................ 29
3.4 Installing the boiler ............................................................................................................................................................................ 31
3.5 Boiler room ventilation ..................................................................................................................................................................... 31
3.6 Air intake and ue gas venting system ......................................................................................................................................... 32
3.7 Checking combustion eciency..................................................................................................................................................... 36
3.8 Connection to gas mains.................................................................................................................................................................. 37
3.9 Hydraulic connections ...................................................................................................................................................................... 37
3.10 Connection to electrical mains ....................................................................................................................................................... 39
3.11 Connection to ambient thermostat (optional) ........................................................................................................................... 39
3.12 Installation of the ambient probe (optional)............................................................................................................................... 39
3.13 Installation and operation with Open Therm Remote Control (optional) ........................................................................... 40
3.14 Selecting the operating range in heating mode......................................................................................................................... 40
3.15 Installation of the (optional) external probe and sliding temperature operation.............................................................. 41
3.16 TSP parameters................................................................................................................................................................................... 43
3.17 Filling the system................................................................................................................................................................................ 47
3.18 Starting up the boiler......................................................................................................................................................................... 47
3.19 Available head .................................................................................................................................................................................... 48
3.20 Wiring diagrams................................................................................................................................................................................. 49
3.21 Adaptation to other gas types and burner adjustment............................................................................................................ 55
4. Testing the boiler................................................................ 57
4.1 Preliminary checks ............................................................................................................................................................................. 57
4.2 Switching on and switching o ...................................................................................................................................................... 57
5. Maintenance ................................................................... 58
5.1 Maintenance schedule...................................................................................................................................................................... 58
5.2 Combustion analysis......................................................................................................................................................................... 58
6. Decommissioning, disassembly and disposal ........................................ 59
7. Malfunctions, possible causes and solutions ......................................... 60
7.1 Troubleshooting ................................................................................................................................................................................. 60

6
Fig. 1 Control panel ..............................................................................................................8
Fig. 2 Filler cock.................................................................................................................15
Fig. 3 Dimensions KC/KR ........................................................................................................20
Fig. 4 Dimensions KRB ..........................................................................................................21
Fig. 5 Model KR wiring diagram .................................................................................................22
Fig. 6 Model KC wiring diagram .................................................................................................23
Fig. 7 Model KR wiring diagram .................................................................................................24
Fig. 8 Paper template ...........................................................................................................30
Fig. 9 Installation examples .....................................................................................................32
Fig. 10 Type C13 - C33 coaxial ducts .............................................................................................34
Fig. 11 Type C12 - C33 coaxial pipes dimensione .................................................................................34
Fig. 12 Split pipe kit 0KITSDOP00................................................................................................35
Fig. 13 Dimensions for split pipes ...............................................................................................35
Fig. 14 Plugs position ...........................................................................................................36
Fig. 15 Hole position ............................................................................................................36
Fig. 16 Connection to gas mains.................................................................................................37
Fig. 17 Condensate drain........................................................................................................38
Fig. 18 Thermoregulation curves ................................................................................................42
Fig. 19 Available head...........................................................................................................48
Fig. 20 Wiring diagram KC.......................................................................................................49
Fig. 21 Wiring diagram KR.......................................................................................................51
Fig. 22 Wiring diagram KRB .....................................................................................................53
Fig. 23 Gas diaphragm replacement .............................................................................................55
Fig. 24 Adjusting CO2 value .....................................................................................................56

7
Tab. 1 Adjustment specifications KC-KR-KRB 24 ..................................................................................25
Tab. 2 General specifications KC .................................................................................................25
Tab. 3 General specifications KR/KRB ............................................................................................26
Tab. 4 KC-KR-KRB 24 combustion data ...........................................................................................26
Tab. 5 ERP and Labelling data - KC 24............................................................................................27
Tab. 6 ERP and Labelling data - KR - KRB 24 ......................................................................................28
Tab. 7 Boiler re-ignition temperature ............................................................................................40
Tab. 8 Limits to be set for TSP parameters and default values in relation to boiler type (TSP0) - I ...................................43
Tab. 9 Limits to be set for TSP parameters and default values in relation to boiler type (TSP0) - II ...................................44
Tab. 10 Limits to be set for TSP parameters and default values in relation to boiler type (TSP0) - III .................................45
Tab. 11 Limits to be set for TSP parameters and default values in relation to boiler type (TSP0) - IV .................................46
Tab. 12 Relationship between "Temperature and Nominal resistance" for temperature probes.....................................54
Tab. 13 Flue CO2 content .......................................................................................................56
Tab. 14 Gas diaphragm diameter (mm) ..........................................................................................56

8Instructions for the user
1. Instructions for the user
1.1 Control panel
6
AD
B C
F
7 4
RESET
8 5
3
1
RESET
2
E
Fig. 1 Control panel
A. DHW setting (+/- DHW).
B. Operating status selection and parameter confirmation.
C. Alarm reset and back to the starting page during parameter selection.
D. CH water temperature (+/- CH) and parameter settings.
E. LCD display.
F. Heating system water pressure gauge.

9
Instructions for the user
Ref. Description Steady on Flashing
1 Alphanumeric indicator Temperature, parameter values and
fault indication. Not used.
2 Parameter indicator Indication of "parameter" inside the
parameter menu. Not used.
3 Flame lighting indicator Lit flame indication. Not used.
4 Central heating indicator CH function activated. Display of CH temperature set-point
or function in progress.
5 RESET indicator It is possible to reset the boiler. Not used.
6 Parameter editing indicator
During parameter editing, the wrench
symbol stays on until the set datum is
confirmed.
When edited parameter value is
confirmed.
7Flue cleaning function indicator
(for the installer) Flue cleaning function in progress. Indicates that you are accessing the
flue cleaning function.
8 DHW indicator DHW function activated. Display of DHW temperature set-
point or DHW function in progress.

10 Instructions for the user
1.2 Interpreting boiler status from display indications
1.2.1 Normal operation
Boiler in STANDBY mode
Boiler in SUMMER mode
No active function
Flow temperature displayed
Boiler in WINTER mode
No active function
Flow temperature displayed
Boiler in CENTRAL HEATING ONLY mode
No active function
Flow temperature displayed
Boiler in SUMMER mode
Domestic hot water withdrawal
DHW temperature displayed
Boiler in WINTER mode
Domestic hot water withdrawal
DHW temperature displayed
Boiler in WINTER mode
CH function active
Flow temperature displayed
Boiler in CENTRAL HEATING ONLY mode
CH function active
Flow temperature displayed
1.2.2 Malfunction
To identify any malfunctions, refer to paragraph Troubleshooting on page 60.

11
Instructions for the user
1.3 Boiler operation
1.3.1 Switching on
DANGER
It is presumed that the boiler has been installed by a qualified installer, it has been commissioned and is ready to operate correctly.
• Open the gas shut-off cock.
• Turn the master switch installed ahead of the boiler to ON.
• The display turns on and indicates the function currently active (see Interpreting boiler status from display indications on page 10).
• Select the boiler operating mode: OFF/SUMMER/WINTER/CH ONLY (see Selecting the operating mode on page 11).
• Set desired CH temperature (see CH function on page 11).
• Set desired DHW temperature (see DHW function on page 12).
• Set the desired room temperature on the ambient thermostat inside the home (if installed).
• If an ambient temperature probe or an external probe is available, set the desired ambient temperature.
WARNING
After a prolonged period with the boiler not in use, and with LPG fired boilers in particular, some starting difficulty may be
encountered.
Before starting the boiler switch on another gas powered device (e.g. kitchen range).
Beware that even by following this procedure, the boiler might still experience some starting difficulties and shut down once or
twice. Press the “RESET” button to restore boiler operation.
1.3.2 Selecting the operating mode
To select the boiler operation mode press BOperating mode selection.
Whenever button is pressed, the following modes are enabled in sequence: "SUMMER", "WINTER", "CH ONLY", "OFF".
"SUMMER" operating status
When the "SUMMER" mode is enabled, only the DHW production function is active.
"WINTER" operating status
When the "WINTER" mode is enabled, both DHW and CH functions are active.
"CH ONLY" operating status
When the "CH ONLY" mode is enabled, only the heating water production function is active.
"OFF" operating status
When the "OFF" mode is enabled, no function is active.
1.3.3 CH function
To set the heating water temperature, press +/- CH buttons.
Heating temperature adjustment range depends on the selected operating range.:
• standard range: from 20°C to 78°C (pressing CH +/-);
• reduced range: from 20°C to 45°C (pressing CH +/-).
Operation range selection is to be implemented by a installer or a qualified Service Centre (see par. Selecting the operating range in heating
mode on page 40).
During temperature setting, the symbol flashes on the screen and the CH current temperature setting is displayed.
When the central heating system requests heat from the boiler, the LCD displays the symbol (blinking) and the current heating flow
water temperature.
The waiting time between one boiler ignition and the following one, used to prevent boiler frequent turning on and off, ranges between 0 and
30 minutes (default value: 4 min.), and can be edited with the P11 parameter.
Should water temperature in the system fall below set minimum value, between 20°C and 78°C (default value 40°C for standard range, 20°C
for reduced range) to be edited with the P27 parameter, the waiting time is reset and the boiler re-ignites.
The burner ON symbol shows while the burner is operating.

12 Instructions for the user
1.3.4 DHW function
The DHW production function is enabled on the KC model and on the KR/KRB models with external water heater (optional).
DHW production function is enabled in one of the following operating modes: SUMMER or WINTER.
Such function has always priority over CH water supply.
To set the domestic hot water temperature, press DHW +/- buttons.
During temperature setting, the symbol flashes on the screen and the DHW current temperature setting is displayed.
When the system requests domestic hot water, the display shows the symbol (blinking) and the current domestic hot water temperature.
The burner ON symbol shows while the burner is operating.
Model KC
For KC model, DHW temperature may be set within a range from +35 °C to +57 °C.
WARNING
A flow limiter is installed within the boiler, which limits DHW output flow rate.
This limit is set to 13 litres per minute.
Models KR/KRB
On KR/KRB models with external water heater (optional) and water heater temperature probe (optional, supplied by the manufacturer;
included in the standard supply for KRB model), temperature range is between 35 °C and 65 °C.
On KR/KRB models with external water heater (optional) and water heater probe (optional, supplied by the manufacturer), every 15 days
the anti-legionella function will be enabled, consisting in raising the water heater temperature to 65°C for 30 minutes independent of other
settings.
1.3.5 Freeze protection function
This boiler is fitted with a freeze protection system, which works when the following functions are activated: OFF/SUMMER/WINTER/CH ONLY.
DANGER
The freeze protection function only protects the boiler, not the whole heating system.
The central heating system can be effectively protected against icing by using specific anti-freeze products that are suitable for multi-metal
systems.
WARNING
Do not use anti-freeze products for car engines, and check the effectiveness of the product used over time.
In case burner cannot be ignited due to the lack of gas, the freeze protection functions are anyway enabled through the circulation pumps.
1.3.5.1 Flow freeze protection function
When the heating water temperature sensor detects a water temperature of +5 °C, the boiler switches on and stays on at its minimum heat
output until the temperature reaches +30 °C or 15 minutes have elapsed.
The pump continues to operate even if the boiler shuts down.
1.3.5.2 Plate heat exchanger freeze protection (only model KC)
When the DHW temperature sensor detects a water temperature of +5°C, the boiler switches on and stays on at its minimum heat output until
the DHW temperature reaches +10°C or 15 minutes have elapsed (the deviating valve is in the DHW position).
During the DHW freeze protection operation the temperature detected by the flow probe is constantly checked, and in case it reaches +60 °C
the burner is switched off.
The burner is switched on again if the operation request in anti-freeze mode is still present and the flow temperature is below +60°C.
The pump continues to operate even if the boiler shuts down.

13
Instructions for the user
1.3.5.3 Water heater freeze protection function (for models KR/KRB with external water heater).
On KR/KRB models with external water cylinder (optional) with NTC probe (10 kΩ @ ß=3435; refer to water cylinder technical specifications),
the frost protection function also protects the water heater.
When water heater probe detects a water temperature of +5 °C, the boiler switches on and stays on at its minimum heat output until the
temperature of the water heater water reaches +10 °C or 15 minutes have elapsed.
The pump continues to operate even if the boiler shuts down.
During the water heater anti-freeze operation the temperature detected by the flow probe is constantly checked, and in case it reaches +60°C
the burner is switched off.
The burner is switched on again if the operation request in anti-freeze mode is still present and the flow temperature is below +60°C.
1.3.5.4 Ambient probe freeze protection function
If the ambient probe detects a temperature below +5° C, a heating request to heat the probe-controlled room is launched.
The heating function ends when the probe ambient temperature reading reaches +6° C.
1.3.6 Anti-seize function
If the boiler remains inactive and connected to the power mains, the circulation pump and the deviating valve will be shortly enabled every
24 hours so as to avoid any shut-down.
The same applies to the relay which can be freely programmed whenever this latter is used to power a recirculation pump or a deviating valve.
1.3.7 Timed post-circulation function
After each central heating, DHW or freeze protection request, the pump continues to be powered for 30 seconds.
If a new central heating, DHW or freeze protection request is received during this period, the post-circulation function is cancelled in order to
fulfil the request.
1.3.8 Timed post-ventilation function
After each central heating, DHW or freeze protection request, the fan continues to work for 10 seconds.
If a new operating request is received during this period, the post-ventilation function is cancelled in order to fulfil the request.
1.3.9 Operation with ambient probe (optional)
Boiler can be connected to an ambient probe (optional - not compulsory, supplied by the manufacturer).
When the ambient temperature is known, the boiler automatically adjusts the heating water temperature by increasing it when the ambient
temperature decreases and decreasing it when the ambient temperature is close to the set one.
Heating water temperature varies based on a programme written inside boiler electronic microprocessor.
When working with a connected ambient probe, the +/- CH buttons are no longer used to set heating water temperature, but to change the
desired ambient temperature.
During temperature setting, the °C icon and the value being set are shown on the display.
As soon as button is released, icon will continue flashing for approx. 3 seconds, and set value will flash as well.
After this time, value is stored and display standard operation will be restored.
To connect the ambient probe refer to Installation of the ambient probe (optional) on page 39
WARNING
Only original ambient probes supplied by the manufacturer must be used.
The use of non-original ambient probes, not supplied by the manufacturer, may affect the operation of the ambient probe itself
and of the boiler.

14 Instructions for the user
1.3.10 Operation with external probe (optional)
Boiler can be connected to a probe measuring the external temperature (optional - not compulsory, supplied by the manufacturer).
Once the external temperature value is known, the boiler will automatically adjust the heating water temperature: increasing it as the
external temperature decreases and decreasing it as the external temperature increases. This will both improve room comfort and reduce fuel
consumption. Standard and reduced range max. temperature values will nevertheless be respected.
This boiler operating mode is called "sliding temperature operation".
Heating water temperature varies based on a programme written inside boiler electronic microprocessor.
When working with an external probe, the CH +/- buttons are no longer used to set heating water temperature, but to edit fictitious ambient
temperature, namely the desired theoretical temperature.
During temperature setting, the °C symbol and the value being set are shown on the display.
For optimal curve adjustment, a position close to +20 °C is recommended.
For further details on "cruising temperature operation", refer to paragraph Installation of the (optional) external probe and sliding temperature
operation on page 41.
WARNING
Only original external temperature probes supplied by the manufacturer must be used.
The use of non-original external probes, not supplied by the manufacturer, may affect the operation of the external probe itself
and of the boiler.
1.3.11 Operation with (optional) remote control
The boiler can also be connected to a Remote Control (optional - not compulsory, supplied by the manufacturer) so as to manage several
boiler parameters, such as:
• boiler status selection.
• ambient temperature selection.
• CH system water temperature selection.
• DHW temperature selection.
• CH system and (optional) external water heater activation time programming
• boiler diagnostics display.
• boiler reset and other parameters.
To connect the Remote Control, see Installation and operation with Open Therm Remote Control (optional) on page40.
WARNING
Only use original Remote Control Units supplied by the manufacturer.
The use of non-original remote controls, not supplied by the manufacturer, may affect Remote Control and boiler operation.
1.4 Boiler shut-down
The boiler shuts down automatically if a malfunction occurs.
To determine the possible causes of malfunction (see Troubleshooting on page 60).
Below is a list of shut-down types and the procedure to follow in each case.
1.4.1 Burner shut-down
Fault code E01 is displayed flashing on the display in the event of burner shut-down due to missing flame.
If this happens, proceed as follows:
• check that the gas cock is open and light a kitchen gas ring for example to check the gas supply;
• once having checked if the fuel is available, press the Reset button to restore burner operation: if, after two starting attempts, the boiler still
fails to start and enters the shut-down mode again, contact a service centre or qualified personnel for maintenance.
WARNING
If the burner shuts down frequently, there is a recurring malfunction, so contact a service centre or a qualified service engineer.

15
Instructions for the user
1.4.2 Shut-down due to overheating
Fault code E02 is shown on the LCD display in the event of flow water temperature overheating. Contact a service centre or a qualified service
engineer to carry out the maintenance.
1.4.3 Shut-down due to incorrect air/flue gas system draught
The boiler is equipped with a safety device for flue gas exhaustion check.
Should an air/flue gas system malfunction occur, the control device will shut-down the boiler by interrupting the gas supply to the boiler and
the LCD will display the E03 code.
In this case, contact a Service Centre or a qualified service engineer to carry out the maintenance.
1.4.4 Shut-down due to low water pressure
Fault code E04 is displayed on the LCD display in the event of shut-down triggered by the water pressure switch.
Fill the system by working on filler cock (A) (see Fig. 2 Filler cock).
Water pressure must be 1÷1.3 bars while the boiler is cold.
In order to restore water pressure, proceed as follows:
• Turn the filler cock anticlockwise to allow water to enter the boiler;
• Keep the filler cock open until the pressure gauge shows a value of 1÷1.3 bar;
• Turn cock clockwise to close it.
Should boiler shuts down frequently occur it means there is boiler malfunction in progress. Contact qualified personnel or an authorised
service centre for maintenance.
DANGER
Make sure you close filler cock (A) carefully after filling procedure is completed.
If you do not, when the pressure increases, the safety valve may activate and discharge water.
A*
A*
A
KC
KR
KRB
Fig. 2 Filler cock
(A*) option.

16 Instructions for the user
1.4.5 Alarm due to temperature probe malfunction
The following fault codes are shown on the display in the event of burner shut-down due to a temperature probe fault:
• E05 for the central heating water probe; iIn this case, the boiler does not work.
• E06 for the DHW probe; in this case, the boiler functions in central heating mode only, and the DHW function is disabled.
• E12 for the boiler probe (KR/KRB model only); in this case the boiler works in heating mode only, whereas the boiler heating function
is disabled.
• E15 for the return probe; in this case the boiler functions normally.
• E23 for the external probe; in this case the boiler works as usual. The operation with external probe is disabled.
• E44 for the ambient probe; in this case the boiler works as usual. The operation with ambient probe is disabled.
WARNING
In any case, contact a service centre or qualified personnel for maintenance.
1.4.6 Alarm due to (optional) Remote Control connection malfunction
The boiler recognises whether or not there is a Remote Control (optional, not compulsory).
If the boiler does not receive information from the Remote Control after the Remote Control itself is connected, the boiler attempts to re-
establish communication for 60 seconds, after which the fault code E31 is shown on the remote control display.
The boiler will continue to operate according to the settings on the touch screen and ignore the Remote Control settings.
WARNING
Contact a service centre or a qualified service engineer to carry out the maintenance.
The remote control can indicate faults or shutdown conditions and can also restore boiler operation after shutdown up to a maximum of 3
times in a 24 hour period.
If the maximum number of attempts is reached, fault code E99 is shown on the boiler display.
To reset error E99, disconnect and re-connect again boiler from/to power mains.
1.4.7 Shut-down for fan malfunction
The fan operation is constantly monitored and in case of malfunction the burner goes off; the code E40 flashes on the display.
This mode is maintained until the fan recovers normal working parameters.
If the boiler does not start and remains in this mode, contact a service centre or a qualified service engineer.

17
Instructions for the user
1.5 Maintenance
WARNING
The boiler must be serviced periodically as indicated in the relevant section of this manual.
Appropriate boiler maintenance ensures efficient operation, environment preservation, and safety for people, animals and objects.
Boilers must be maintained by qualified personnel only, under the requirements set forth by the prevailing rules.
1.6 Notes for the user
WARNING
The user may only access parts of the boiler that can be reached without using special equipment or tools.The user is not authorised
to remove the boiler casing or to operate on any internal parts.
No one, including qualified personnel, is authorised to modify the boiler.
The manufacturer shall not be held responsible in case of damage to people, animals, or property due to failure to follow the above
mentioned instructions.

18 Technical features and dimensions
2. Technical features and dimensions
2.1 Technical features
This boiler is equipped with a fully pre-mixed gas burner. The following models are available:
• KC condensing boiler with sealed chamber and forced draught, supplying CH water and instant DHW production;
• KR condensing boiler with sealed chamber and forced draught, supplying CH water only.
• KRB condensing boiler with sealed chamber and forced draught, supplying CH water only; with 3-way deviating valve for connection
to external water heater (optional).
The following power rates are available:
• KC/KR/KRB 24: with heat input of 23.7 kW
All models are equipped with electronic ignition and ionisation flame sensing device.
The boilers meet local applicable Directives enforced in the country of destination, which are stated on their rating plate.
Installation in any other country may be a source of danger for people, animals and property.
The key technical features of the boilers are listed below.
2.1.1 Manufacturing characteristics
• IPX4D electrically protected control panel.
• Integrated, modulating electronic safety board.
• Electronic start-up with built-in igniter and ionisation flame detection.
• Stainless steel, fully pre-mixed burner.
• Mono-thermal, high efficiency heat exchanger, made of aluminium, with manual air purging device.
• Twin shutter modulating gas valve with constant air/gas ratio.
• Modulating, electronically managed combustion fan.
• High-efficiency CH circulation pump with built-in air purging device.
• Minimum pressure switch.
• Heating flow water temperature probe.
• DHW temperature probe (KC).
• Limit thermostat.
• Flue gas thermostat on discharge tower
• Air pressure switch
• Integrated, automatic by-pass.
• 7 litre expansion vessel.
• System filler cock (KC).
• System water discharge tap.
• DHW plate heat exchanger made of stainless steel (KC).
• Motorised deviating valve (KC/KRB).
• DHW priority switch (KC).
• 13 l/min DHW flow-limiting device (KC).
2.1.2 User interface
• Liquid crystal LCD interface for displaying and setting the boiler operating status: OFF, SUMMER, WINTER and CH ONLY.
• CH water temperature regulator: 20-78°C (standard range) or 20-45°C (reduced range).
• DHW water temperature regulator: 35-57°C (KC) - 35÷65°C (KR/KRB with optional water heater).
• System water pressure gauge.

19
Technical features and dimensions
2.1.3 Operating features
• CH electronic flame modulation with timer-controlled rising ramp (30 minutes, adjustable).
• DHW electronic flame modulation (mdoels KC and KR/KRB with optional water heater).
• DHW priority function (model KC and models KR/KRB with optional water heater)
• Flow freeze protection function: ON 5°C; OFF 30°C or after 15 minutes of operation if CH temperature > 5 °C.
• DHW freeze protection function: ON 5°C; OFF 30°C or after 15 minutes of operation if CH temperature > 5 °C.
• Water heater anti-freeze function (KR with optional external water heater with NTC probe): ON 5°C; OFF 10 °C or after 15 minutes of
operation if water heater temperature > 5 °C.
• Timer-controlled flue cleaning function: 15 minutes.
• Anti-legionella function (models KR/KRB with optional water heater).
• CH Maximum heat input parameter adjustment.
• Ignition heat input adjustment parameter.
• Possibility to select the heating range: standard or reduced.
• Ignition flame propagation function.
• CH thermostat timer: 30 minutes (adjustable).
• Heating pump post-circulation function in CH, freeze protection and flue cleaning modes: 30 seconds (adjustable).
• DHW post-circulation function (KC and KR/KRB with optional water heater): 30 seconds.
• Post-circulation function for heating temperature > 78 °C: 30 seconds.
• Post-ventilation function after working: 10 seconds.
• Post-ventilation function for CH temperature >95 °C.
• Circulation pump and deviating valve anti shut-down function: 10 seconds of operation after 24 hours of inactivity (adjustable).
• Anti-water hammer function: can be set from 0 to 10 seconds through parameter P15.
• Ready for connection to an (optional) ambient thermostat.
• Ready for operation with an external probe (optional, supplied by the manufacturer).
• Ready for operation with an ambient probe (optional, supplied by the manufacturer).
• Ready for operation with an OpenTherm remote control (optional, supplied by the manufacturer).

20 Technical features and dimensions
2.2 Dimensions
114 31
66 60 62 67 82 63
81
91
700
400
245
152,5
52
126
250
R
M
CGF
S
Fig. 3 Dimensions KC/KR
S Trap inspection cap
M CH system flow (3/4”)
C Domestic hot water outlet (1/2”, only KC)
G Gas inlet (1/2”)
F Cold water inlet (1/2")
R CH system return (3/4”)