Fondital LINE Tech Quick start guide

IST 03 C 397 - 02
INSTALLATION
USE AND MAINTENANCE
NIAS CONDENSING
GB

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Dear Customer,
Thank you for choosing and buying one of our boilers. Please read these instructions carefully in order to install, operate and
service the boiler properly.

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General information for fitters, maintenance technicians and users
This INSTRUCTION MANUAL, which is an integral and indispensable part of the product, must be handed over to the user by
the fitter and must be kept in a safe place for future reference. The manual must accompany the boiler should it be sold or its
possession transferred.
This boiler is designed for connection to a central heating system and to a hot domestic water system.
Any other use is considered incorrect and therefore dangerous.
The boiler must be installed in compliance with the applicable laws and standards and according to the manufacturer’s
instructions given in this manual. Incorrect installation may cause injury to people or animals and damage to property. The
manufacturer shall not be held liable for any such injury or damage.
Damage or injury caused by incorrect installation or use, or by failure to follow the manufacturer’s instructions will relieve
manufacturer of 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 has not been damaged during transport and handling. Do not install equipment which is
damaged or faulty.
Do not obstruct the air intake or heat dissipation openings.
Only Manufacturer-approved accessories with optional electric or other kits must be installed.
All the packaging materials can be recycled and must be disposed of correctly. They must be sent to a specific waste
management site.
Keep the packaging out of the reach of children as it may represent a hazard.
In the event of failure or faulty operation, switch off the boiler. Do not attempt to make any repairs and contact a qualified
technician. Manufacturer-approved parts must be used for all repairs to the boiler.
Failure to comply with the above requirements may affect the safety of the boiler and endanger people, animals and property.
Routine boiler maintenance should be performed according to the schedule in the relevant section of this
manual. Appropriate boiler maintenance ensures efficient operation, preservation of the environment, and
safety for people, animals and property. Incorrect and irregular maintenance can be a source of danger for
people, animals and property.
The Manufacturer recommends that Customers contact a Service Centre or a qualified fitter for maintenance and repairs.
If the boiler is to remain inactive for a long time, disconnect it from the power mains and close the gas tap.
Warning! If the boiler is disconnected from the mains, the electronic anti-freeze function will not operate.
Should there be a risk of freezing, add anti-freeze to the heating system. It is not advisable to empty the system as this may
result in damage. Use specific anti-freeze products suitable for multi-metal heating systems.
If you smell gas:
- do not touch any electrical switches and do not turn on electrical appliances;
- do not ignite flames and extinguish any cigarettes;
- close the main gas tap;
- open doors and windows;
- contact a Service Centre, a qualified fitter or the gas supply company.
Never use a flame to detect a gas leak.
This boiler has been built for installation in the country indicated on packaging /rating plates.
Installation in a country other than the specified one may be a source of danger for people, animals and
property.
The Manufacturer cannot be held contractually or extra-contractually liable in the event of failure to comply with the
above.

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Rapid operating instructions
The following instructions will help you to switch the boiler on quickly and regulate it for immediate use.
It is presumed that the boiler has been installed by a qualified fitter, it has been used before and is ready to operate
correctly.
If any accessories have been fitted on the boiler, these instructions will not cover them. You will therefore have to refer to
the full boiler instructions as well as to the specific instructions for the accessories.
This manual contains full details of how the boiler works, and full operating and safety instructions.
1. Open the gas cock upstream the boiler.
2. Turn the master switch to ON: the display comes on and shows the function set via the boiler selector (2in fig. 1).
3. If you do not wish to activate the heating function, turn the boiler selector (2, fig. 1) to SUMMER. This will activate domestic hot water
(DHW) only, and the display will show the flow water temperature.
4. If you wish to activate the heating function, turn the boiler selector (2, fig. 1) to WINTER. This will activate both DHW and heating, and the
display will show the flow water temperature.
5. Decide whether you wish to activate the Aqua Premium system and proceed as follows to regulate the hot water temperature.
Turn regulator (3, fig. 1) anticlockwise as far as it will go. The water storage symbol is displayed, showing that the Aqua Premium system
is active (if it was already active, this operation deactivates it). Then turn the selector (3) until the desired hot water temperature value is
displayed (at least 40°C).
While the DHW temperature is being regulated, the display shows the temperature setting and the DHW symbol flashes.
6. To regulate the CH water temperature, first set the regulator (4, fig. 1) to 3 o’clock (about 70°C), then regulate it as required. While the DHW
temperature is being regulated, the LCD displays the temperature setting and the CH symbol flashes.
7. Set the desired temperature on the (optional) room thermostat in the building.
The boiler is now ready to operate.
If the boiler shuts down, turn the boiler selector (2in fig. 1) to reset for a few seconds, then back to the desired position. If the boiler does not
restart, contact a Service Centre.
Boiler selector on SUMMER
Boiler selector on WINTER
DHW temperature regulator
CH water temperature regulator
Boiler selector on RESET
Liquid crystal display LCD
Liquid crystal display LCD

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TABLE OF CONTENTS
General information for fitters, maintenance technicians and users..........................................................................................................................................3
Rapid operating instructions...........................................................................................................................................................................................................................4
1. User instructions...............................................................................................................................................................................................................................................7
1.1. Control panel...........................................................................................................................................................................................................................................7
1.2. LCD ......................................................................................................................................................................................................................................................8
1.3. BOILER STATUS – LCD ACTIVATION Correspondence...............................................................................................................................................................9
1.4. Operating the boiler.............................................................................................................................................................................................................................10
1.4.1. Switching on......................................................................................................................................................................................................................................10
1.4.2. CH function......................................................................................................................................................................................................................................10
1.4.3. DHW function ................................................................................................................................................................................................................................. 10
1.4.3.1. AQUA PREMIUM system................................................................................................................................................................................................10
1.4.3.2. Instantaneous production of DHW...........................................................................................................................................................................11
1.4.4. Anti-freeze function......................................................................................................................................................................................................................11
1.4.5. Pump and valve anti-shutdown function ............................................................................................................................................................................12
1.4.6. Operation with (optional) remote control ...........................................................................................................................................................................12
1.4.7. Operation with an (optional) external probe .....................................................................................................................................................................12
1.5. Boiler shutdown.....................................................................................................................................................................................................................................13
1.5.1. Burner shutdown.............................................................................................................................................................................................................................13
1.5.2. Shutdown due to overheating ..................................................................................................................................................................................................13
1.5.3. Shutdown due to air/flue gas system malfunction ...........................................................................................................................................................13
1.5.4. Shutdown due to low fluid level...............................................................................................................................................................................................13
1.5.5. Shutdown due to fan malfunction...........................................................................................................................................................................................14
1.5.6. Alarm due to temperature probe malfunction ...................................................................................................................................................................14
1.5.7. Alarm due to gas valve modulator malfunction.................................................................................................................................................................14
1.5.8. Alarm due to (optional) remote control connection malfunction...............................................................................................................................14
1.5.9. Alarm due to (optional) external probe malfunction .......................................................................................................................................................14
1.6. Maintenance............................................................................................................................................................................................................................................14
1.7. Notes for the user ..................................................................................................................................................................................................................................14
2. Technical features and dimensions..........................................................................................................................................................................................................15
2.1. Technical features ..................................................................................................................................................................................................................................15
2.2. Dimensions ..............................................................................................................................................................................................................................................16
2.3. Plumbing system ...................................................................................................................................................................................................................................17
2.4. Operating data........................................................................................................................................................................................................................................18
2.5. General characteristics.........................................................................................................................................................................................................................18
2.6. Available head.........................................................................................................................................................................................................................................19
3. Instructions for the fitter ..............................................................................................................................................................................................................................20
3.1. Installation standards...........................................................................................................................................................................................................................20
3.2. Installation................................................................................................................................................................................................................................................20
3.2.1. Packaging.........................................................................................................................................................................................................................................20
3.2.2. Choosing where to install the boiler......................................................................................................................................................................................20
3.2.3. Positioning the boiler ..................................................................................................................................................................................................................20
3.2.4. Installing the boiler.......................................................................................................................................................................................................................22
3.2.5. Boiler room ventilation ...............................................................................................................................................................................................................22
3.2.6. Air intake / flue gas discharge system...................................................................................................................................................................................23
3.2.6.1. Air/flue gas system duct configuration: B23, B53, C13, C33, C43, C53, C83..............................................................................................24
3.2.6.2. Ø 100/60 mm and Ø 125/80 mm air/flue gas coaxial ducts system ............................................................................................................25
3.2.6.3. Ø 80 mm air/flue gas split ducts system.................................................................................................................................................................26
3.2.7. Testing combustion efficiency..................................................................................................................................................................................................26
3.2.7.1. “Chimney sweep” function ........................................................................................................................................................................................... 26
3.2.7.2. Measurement procedure..............................................................................................................................................................................................27
3.2.8. Gas mains connection.................................................................................................................................................................................................................28
3.2.9. Plumbing connections ................................................................................................................................................................................................................28
3.2.10. Power mains connection...............................................................................................................................................................................................29
3.2.11. Selecting central heating output range...................................................................................................................................................................29
3.2.12. Connection to the room thermostat (optional)....................................................................................................................................................29
3.2.13. Connection to an OpenTherm remote control (optional).................................................................................................................................29
3.2.14. Connection to an (optional) external probe and “sliding temperature” operation ................................................................................30
3.3. Filling the system...................................................................................................................................................................................................................................32
3.4. Starting the boiler .................................................................................................................................................................................................................................32
3.4.1. Preliminary checks .........................................................................................................................................................................................................................32
3.4.2. Switching on and off.....................................................................................................................................................................................................................32
3.5. Wiring diagram .......................................................................................................................................................................................................................................33
3.6. Adapting to other gases and regulating the burner................................................................................................................................................................34
3.6.1. Switching from METHANE to PROPANE.................................................................................................................................................................................34
3.6.2. Switching from PROPANE to METHANE.................................................................................................................................................................................34
3.6.3. Burner adjustment.........................................................................................................................................................................................................................34
4. Testing the boiler ..............................................................................................................................................................................................................................................35
4.1. Preliminary checks.................................................................................................................................................................................................................................35
4.2. Switching on and off ............................................................................................................................................................................................................................35
5. Maintenance ......................................................................................................................................................................................................................................................36
5.1. Maintenance schedule.........................................................................................................................................................................................................................36
5.2. Combustion analysis.............................................................................................................................................................................................................................36
6. Troubleshooting................................................................................................................................................................................................................................................37

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LIST OF FIGURES
fig. 1 - Control panel................................................................................................................................................................................................................................................7
fig. 2 - LCD ..................................................................................................................................................................................................................................................................8
fig. 3 - Calculated temperature ...........................................................................................................................................................................................................................12
fig. 4 - Thermoregulation curves ........................................................................................................................................................................................................................12
fig. 5 - Filling tap .......................................................................................................................................................................................................................................................13
fig. 6 - Dimensions ...................................................................................................................................................................................................................................................16
fig. 7 - Plumbing system........................................................................................................................................................................................................................................17
fig. 8 - Available head .............................................................................................................................................................................................................................................19
fig. 9 - Wall-mounting template..........................................................................................................................................................................................................................21
fig. 10 - Filter...............................................................................................................................................................................................................................................................22
fig. 11 - Installation examples..............................................................................................................................................................................................................................23
fig. 12 - Air/flue gas coaxial ducts system.......................................................................................................................................................................................................25
fig. 13 - Dimensions for coaxial ducts connections.....................................................................................................................................................................................25
fig. 14 - Air/flue gas split ducts system ............................................................................................................................................................................................................26
fig. 15 - Dimensions for split ducts connections ..........................................................................................................................................................................................26
fig. 16 - Opening the casing.................................................................................................................................................................................................................................27
fig. 17 - Chimney-sweep function......................................................................................................................................................................................................................27
fig. 18 - Air intake/flue gas discharge turret...................................................................................................................................................................................................27
fig. 19 - Reading points for calculating combustion efficiency...............................................................................................................................................................27
fig. 20 - Gas mains connection............................................................................................................................................................................................................................28
fig. 21 - Thermoregulation trimmer...................................................................................................................................................................................................................31
fig. 22 - Heating curves for operation with an external probe................................................................................................................................................................31
fig. 23 - Wiring diagram..........................................................................................................................................................................................................................................33
fig. 24 - Adapting to other gases........................................................................................................................................................................................................................34
fig. 25 - Gas valve regulation................................................................................................................................................................................................................................35
LIST OF TABLES
Table 1 - BOILER STATUS - LCD visualisation correspondence (normal operation) .........................................................................................................................9
Table 2 - BOILER STATUS - LCD visualisation correspondence (malfunction)....................................................................................................................................9
Table 3 - KB 24 model setting rates...................................................................................................................................................................................................................18
Table 4 - KB 28 model setting rates...................................................................................................................................................................................................................18
Table 5 - General specifications ..........................................................................................................................................................................................................................18
Table 6 - Combustion data for model KB 24 ..................................................................................................................................................................................................19
Table 7 - Combustion data for model KB 28 ..................................................................................................................................................................................................19
Table 8 - Burner re-ignition temperatures ......................................................................................................................................................................................................29
Table 9 - Limits to be set for TSP parameters and default values in relation to boiler type (TSP0)...........................................................................................30
Table 10 - TSP chart of parameters which can be displayed (these parameters cannot be adjusted via remote control) ..............................................30
Table 11 - Relation between the temperature (°C) and nominal resistance (Ohm) of temperature probes..........................................................................33
Table 12 - CO2rates..................................................................................................................................................................................................................................................34

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1. User instructions
1.1. Control panel
1. Liquid crystal display (LCD)
The LCD displays the boiler status and operating data (see fig. 2).
2. Boiler mode selector
With the selector on RESET the boiler restarts after activation of the burner shutdown device.
With the selector on OFF, the boiler is in stand-by mode, with the heating and hot water functions disabled.
With the selector on SUMMER the boiler is ready to produce domestic hot water only.
With the selector on WINTER the boiler is ready to heat and produce hot water.
With the selector on ANTI-FREEZE only the anti-freeze function is enabled.
3. DHW temperature regulator
This is used to enable/disable water storage tank and to set the DHW temperature in the range 35-57°C.
4. CH water temperature regulator
This is used to select the temperature of the water in the heating system in the range 20-78°C (when standard temperature range is selected)
or 20-45°C (when reduced temperature range is selected).
5. Water pressure gauge
This shows the pressure of the water in the heating system.
fig. 1
1
2345

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1.2. LCD
a. DHW indicator
This comes on when the boiler is in DHW mode.
It flashes when the DHW temperature is being regulated via regulator 3(fig. 1).
b. Water heater on indicator
This indicator comes on when the water heater is activated via regulator 3(fig. 1).
c. Alphanumeric indicator
This shows the following:
- CH flow temperature
- CH temperature setting
- DHW temperature setting
- boiler status
- boiler diagnostics
d. Central heating indicator
This comes on when the boiler is in CH mode.
It flashes when the CH temperature is being regulated via regulator 4(fig. 1).
e. Boiler shutdown indicator
This comes on when there is a malfunction that cannot be reset via the boiler function selector 2(fig. 1).
The problem must be solved before the boiler can be restarted.
f. Burner shutdown indicator
This comes on when the burner shutdown device activates due to a malfunction.
To restart the boiler, turn the boiler selector 2(fig. 1) to the RESET position for a few seconds and then back to the desired position.
g. Flame indicator
This comes on when the burner flame is present.
h. Chimney-sweep function indicator (for fitter only)
This flashes when the chimney-sweep function is activated.
The flow water temperature and the number of fan rounds are shown alternatively (in this case, symbol mis also shown)
i. Thermoregulation indicator (for fitter only)
This comes on when the thermoregulation curve is being set.
l. Calculated ambient temperature indicator
When an external probe is installed, this indicator flashes when the calculated ambient temperature is set via regulator 4.
m. Number of fan rounds (for fitter only)
When the chimney sweep function is activated, symbol hflashes and flow water temperature and number of fan rounds are shown
alternatively (in this case, the correspondent symbol is also shown).
fig. 2
a b c d
e
f g h i l m
m
Rpm x 10

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1.3. BOILER STATUS – LCD ACTIVATION Correspondence
Normal operation
Boiler selector on OFF
Boiler selector on ANTI-FREEZE
Boiler selector on SUMMER or WINTER
No function active
The water flow temperature is displayed
Boiler selector on SUMMER or WINTER
Aqua Premium system enabled, no function active
The water flow temperature is displayed
Boiler selector on WINTER
CH function active (Aqua Premium system disabled)
The water flow temperature is displayed
Boiler selector on SUMMER or WINTER
CH function active
The water flow temperature is displayed
Table 1 - BOILER STATUS - LCD visualisation correspondence (normal operation)
Malfunction
Boiler not powered on
Boiler shutdown due to flame absence
Boiler shutdown due to safety thermostat activation
Boiler shutdown due to flue gas thermostat activation
CH probe failure
DHW probe failure
Storage probe fault
Low primary fluid level alarm or minimum pressure switch
activation
(pump ON – flow switch OPEN)
Low primary fluid level alarm
(pump OFF – flow switch CLOSE)
Fan failure
Remote control connection failure
External probe failure
Table 2 - BOILER STATUS - LCD visualisation correspondence in case of malfunctions

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1.4. Operating the boiler
1.4.1. Switching on
It is presumed that the boiler has been installed by a qualified fitter, it has been used before and is ready to operate
correctly.
• Open the gas cock;
• Turn the master switch to ON – the LCD light up and shows the active function (see table 1);
• Choose the boiler mode via selector 2 (g. 1): OFF/SUMMER/WINTER/ANTI-FREEZE;
• Set the temperature for the heating system on regulator 4 (g. 1);
• Set the DHW temperature on regulator 3 (g. 1);
• Set the ambient temperature on the (optional) thermostat
IMPORTANT
If the boiler is not used for a long time, particularly when it runs on propane gas, ignition may be difficult. So, before starting the
boiler, switch on a different gas-fired device (e.g. a cooking ring).
Note that the boiler may still shut down a couple of times. If this happens, turn selector 2 (fig. 1) to the RESET position for a few
seconds, then back to the desired position.
1.4.2. CH function
Set desired CH water temperature via no. 4 knob (g. 1);
CH water temperature adjusting range depends on selected operation range:
• standard range: from 20°C to 78°C (from full counter-clockwise position to full clockwise position);
• reduced range: from 20°C to 45°C (from full counter-clockwise position to full clockwise position).
Operation range choice is to be selected by the fitter or a qualified Service Centre.
During temperature setting, the CH symbol on the LCD flashes and the CH setting is displayed.
When the CH system requests heat, the LCD shows the (fixed) CH symbol and the temperature of the CH water.
The burner symbol only shows while the burner is operating.
To prevent frequent ignition and switching off in central heating mode, boiler is programmed to have a waiting
time between subsequent ignitions which depends on the selected operating range.
• standard range: 4 minutes;
• reduced range: 2 minutes.
Should water temperature in the system fall below the default value, waiting time procedure is aborted and boiler re-ignited (see par. 3.2.11).
1.4.3. DHW function
The boiler always gives priority to DHW demand over the CH function.
The boiler is equipped with the AQUA PREMIUM system, which combines the instantaneous production of domestic hot water with a storage
function.
1.4.3.1. AQUA PREMIUM system
The boiler comes with a 25-litre stratification storage tank and a secondary plate heat exchanger.
The boiler can either function as a standard instantaneous boiler, when the storage tank is deactivated, or with the innovative Aqua Premium
system, when the storage tank is switched on.
The storage tank function is controlled via regulator 3(fig. 1).
When regulator 3is turned fully anticlockwise, the storage tank symbol is displayed. Then turn regulator 3clockwise
until a setting of at least 40°C is reached.
To deactivate the water storage tank function, turn regulator 3fully anticlockwise until the symbol disappears, then
back to a setting of at least 40°C.
The temperature range is 35-57°C (from the fully anticlockwise to the fully clockwise position of regulator 3).
During temperature setting, the DHW symbol on the LCD flashes and the water temperature is displayed.
In Aqua Premium mode, when a hot water tap is turned on, the flow switch cuts off the supply of water. The boiler
switches on, the cutoff valve opens and the DHW pump activates (the pump flow rate is fixed).
When DHW demand is less than the pump’s flow rate, water to the tap is only supplied by the secondary plate heat exchanger and excess
DHW is deviated to the storage tank.
When the DHW demand exceeds the flow rate, water produced by the secondary heat exchanger is added to that from the storage tank. This
gives a higher hot water flow than the one produced by instantaneous boilers with an identical thermal output and traditional ones with a
storage tank of the same capacity.

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When there is a demand for domestic hot water, the tap symbol (fixed) and the instantaneous water temperature
are displayed.
The burner symbol shows while the burner is in operation.
The boiler can also operate as a standard instantaneous boiler, when the storage tank disabled.
1.4.3.2. Instantaneous production of DHW
When the storage tank is disabled, the boiler operates as a standard instantaneous boiler: the cutoff valve is closed and the DHW pump is off.
In this case, DHW demand is met by the secondary heat exchanger only and the maximum quantity of hot water supplied depends on the
boiler thermal output.
The temperature can be selected on regulator 3in the range 35-57°C (from the fully anticlockwise to the fully
clockwise position).
During temperature setting, the DHW symbol on the LCD flashes and the DHW temperature is displayed.
The DHW flow rate in litres per minute at the set temperature depends on the boiler’s thermal output and the water
supply temperature. It can be calculated from the following formula:
K
l = litres of hot water per minute = --------
ΔT
where K is
• 401 for model KB 24
• 444 for model KB 28
and ΔT = DHW temperature – cold water supply temperature
For instance, with model KB 24, if the water supplied is 8°C and you want shower water at 38°C, the value of ΔT is:
Δt = 38 °C – 8 °C = 30 °C
and the number of DHW litres per minute available at 38°C is:
401
l = ------------- = 13.4 litres per minute
30
When there is a demand for hot water, the tap symbol (fixed) and the instantaneous flow water temperature are displayed.
The burner symbol shows while the burner is in operation.
1.4.4. Anti-freeze function
The boiler comes with an anti-freeze function which is active in SUMMER, WINTER and ANTI-FREEZE modes.
The anti-freeze function protects the boiler only, not the whole heating system.
The heating system must be protected by a room thermostat, which is disabled when selector 2 is on ANTI-FREEZE or OFF.
So, if you wish to protect the heating system as well, turn selector 2 to WINTER .
The heating system can also be protected effectively from frost by using specific anti-freeze products suitable for multi-metal systems.
Do not use vehicle anti-freeze products. Periodically check the effectiveness of the additive.
When the heating water temperature sensor reads a temperature of 5°C, the boiler switches on at minimum thermal output until the
temperature rises to 30°C or 15 minutes have elapsed.
If the boiler shuts down, the pump continues to operate.
When the DHW temperature sensor reads a temperature of 5°C, the boiler switches on at minimum thermal output until the temperature
rises to 10°C or 15 minutes have elapsed (the switching valve switches to the DHW position).
If the boiler shuts down, the pump continues to operate.
When the storage tank temperature sensor reads a temperature of 5°C, the boiler switches on at minimum thermal output until the
temperature rises to 10°C or 15 minutes have elapsed.
If the boiler shuts down, the pump continues to operate.

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1.4.5. Pump and valve anti-shutdown function
If the boiler remains inactive and selector 2is not in the OFF position, and the boiler is still connected to the mains supply, the pump, the
switching valve and the two-way valve activate briefly every 24 hours to keep them efficient.
1.4.6. Operation with (optional) remote control
The boiler can be linked to an (optional, can be supplied by the Producer) remote control, which can be used for setting numerous
parameters, including:
• boiler status;
• ambient temperature;
• CH system water temperature;
• DHW system water temperature;
• CH system activation times and storage activation times;
• boiler diagnostics display;
• boiler reset,
and other parameters
For instructions on how to connect the remote control, refer to subsection 3.2.13.
Only original remote controls supplied by the manufacturer must be used.
If non-original remote controls are used, correct operation of the boiler, or of the remote control, cannot be guaranteed.
1.4.7. Operation with an (optional) external probe
The boiler can be connected to an (optional) external temperature probe.
When the external temperature has been measured, the boiler automatically regulates the heating water temperature, increasing it when the
outside temperature drops and decreasing it when it rises, which improves comfort and saves fuel (this is referred to as sliding temperature
operation).
The heating water temperature varies according to a program in the boiler’s microprocessor.
When an external probe is installed, the DHW temperature 4 looses its heating water temperature function and becomes a calculated
ambient temperature regulator (fig. 3) for the temperature desired in the areas to be heated.
During temperature setting, the calculated ambient temperature symbol flashes and the temperature
setting is displayed.
Regulator 4in the fully anticlockwise position corresponds to a calculated
ambient temperature of 15°C, 9 o’clock corresponds to 18°C, 12 o’clock to 25°C, 3
o’clock to 32°C and the fully clockwise position to 35°C.
To get an optimal curve, a setting of approximately 20°C is recommended
Only original external probes supplied by the manufacturer must be used.
If non-original external probes are used, correct operation of the boiler, or of the probe, cannot be guaranteed.
fig. 4
25
18 32
15 35
fig. 3
Fig. 4 shows the curves for a calculated
temperature of 20°C. When this value is
increased or decreased via regulator 4, the
curves move up or down, respectively.
With this setting, for instance, if you select
the curve corresponding to parameter 1 and
the outdoor temperature is -4°C, the CH flow
temperature will be 50°C.
Flow temperature [°C]
Thermoregulation curve coefficient
Outdoor temperature [°C]

13
fig. 5
1.5. Boiler shutdown
The boiler shuts down automatically if a malfunction occurs.
Refer to Tables 1 and 2 to identify the boiler operating mode.
Refer to Table 2 and section 6 to identify possible causes of the shutdown. The troubleshooting section is at the end of this manual.
Below is a list of kinds of shutdown and the procedure to follow in each.
1.5.1. Burner shutdown
If the burner shuts down as there is no flame, the burner shutdown symbol is displayed and code E01 flashes.
If this happens, proceed as follows:
• check that the gas cock is open and light a gas ring for example to check the gas supply;
• if the gas supply is normal, turn selector 2to the reset position for 2 seconds, then back to the desired position. If after three attempts
the burner still fails to ignite, contact a qualified Service Centre or service engineer.
If the burner shuts down frequently, there is a recurring malfunction, so contact an Authorised Service Centre or a qualified service
engineer.
1.5.2. Shutdown due to overheating
If the water temperature is too high, the boiler will shut down. The burner shutdown symbol is displayed and code E02 flashes. Contact
a qualified Service Centre or service engineer.
1.5.3. Shutdown due to air/flue gas system malfunction
If the air/flue gas system malfunctions, the boiler shuts down. The burner shutdown symbol symbol is displayed and code E20
(differential pressure switch cut-in) flashes.
Contact a qualified Service Centre or service engineer.
1.5.4. Shutdown due to low fluid level
If water circulation in the DHW circuit is incorrect, the boiler shuts down.
The LCD displays the boiler shutdown symbol and the E10 or E26 codes flashing, depending on the type of malfunction.
In the former case (code E10 flashing), there may be 2 possible reasons:
a) The pressure gauge (5 in fig. 1) shows a pressure value below 1 bar
Fill the system with water as detailed below:
• Turn the lling tap (g. 5) anticlockwise to allow water to enter the boiler;
• Keep the tap open until the pressure gauge shows a value of 1÷1.3 bar;
• Turn the tap fully clockwise to close it;
• Turn selector 2to the RESET position for a few seconds, then back to the desired position.
If the boiler still fails to operate, contact a qualified Service Centre or service engineer.
Make sure you close the tap carefully after filling.
If you do not, when the pressure increases, the safety valve may activate and discharge water.
b) The pressure gauge (5 in fig. 1) shows a pressure value of 1÷1.3 bar
Contact an Authorised Service Centre or a qualified service engineer.
In the latter case (code E26 flashing) contact a qualified Service Centre or service engineer.
Filling tap

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1.5.5. Shutdown due to fan malfunction
IlThe fan work is constantly monitored and in case of malfunction it goes o; the boiler shutdown symbol is
displayed and code E17 flashes.
This mode is maintained until the fan recovers normal working parameters.
If the boiler should not start and remain in this mode, contact a qualified Service Centre or service engineer.
1.5.6. Alarm due to temperature probe malfunction
If the burner shuts down due to malfunction of the temperature probes, the boiler shutdown symbol is displayed and the following
codes may flash:
• E05, CH probe:
the boiler does not work.
• E06, DHW probe:
the boiler only operates in CH mode, not DHW mode.
• E12, storage probe:
the boiler operates in CH and instantaneous DHW mode.
Contact a qualified Service Centre or service engineer.
1.5.7. Alarm due to gas valve modulator malfunction
If the gas valve modulator malfunctions, the boiler shutdown symbol is displayed and code E16 flashes.
The boiler will continue to operate, but at the minimum available output.
Contact a qualified Service Centre or service engineer.
1.5.8. Alarm due to (optional) remote control connection malfunction
The boiler recognises whether or not there is a remote control (optional). If the remote control is connected but
the boiler does not receive instructions, the boiler shutdown symbol is displayed and code E22 flashes.
The boiler will continue to operate according to the settings on the control panel (fig. 1) and ignore the remote control settings.
Contact a qualified Service Centre or service engineer.
1.5.9. Alarm due to (optional) external probe malfunction
If the (optional) external temperature probe malfunctions, the boiler shutdown symbol is displayed and code
E23 flashes.
The boiler will continue to operate, but the sliding temperature function is deactivated. The temperature of the
CH water is regulated according to the position of regulator 4(fig. 1), which in this case loses its function as a calculated room temperature
regulator (see par.1.4.7.).
Contact a qualified Service Centre or service engineer.
1.6. Maintenance
The boiler must be serviced periodically as indicated in the relevant section of this manual.
Correct maintenance of the boiler will allow it to work efficiently, without harming the environment, and in complete safety.
Maintenance and repairs must be performed by qualified personnel.
The user is strongly advised to have the boiler serviced and repaired by one a fully qualified Service Centres.
Refer to Section 5 – Maintenance for detailed instructions.
The user may only clean the external casing of the boiler, using ordinary furniture cleaning products.
Do not use water.
1.7. Notes for the user
The user may only access parts of the boiler that can 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 cannot be held liable for damage or injury due to tampering of the boiler or improper intervention.
If the boiler remains inactive and the power supply is switched off for a long time, it may be necessary to reset the pump.
This involves removing the casing and accessing internal parts, so it must only be done by suitably qualified personnel.
Pump failure can be avoided by adding to the water filming additives suitable for multi-metal systems.

15
2. Technical features and dimensions
2.1. Technical features
The boiler is equipped with a fully pre-mixed gas burner. The following models are available
KB 24 condensing boiler with sealed chamber and forced draught, supplying CH water and instant DHW with Aqua Premium system,
heat output 23.7 kW
KB 28 condensing boiler with sealed chamber and forced draught, supplying CH water and instant DHW with Aqua Premium system,
heat output 26.2 kW
These boilers meet all the requirements in the country of destination indicated on the rating plate.
Installation in a different country may cause a hazard for people, animals and property.
The main technical features of the boiler are given below.
Construction characteristics
- IPX4D electrically protected control panel
- Electronic safety board and integrated modulation
- Electronic ignition with separate igniter and ionization flame
detector
- Stainless steel, fully pre-mixed burner
- Mono-thermal, high efficiency, composite and stainless steel
heat exchanger with air purging device
- DHW stainless steel plate heat exchanger
- Twin shutter, modulating gas valve with constant air/gas ratio
- Modulating, electronically managed flue gas discharge fan
- 3-speed CH pump with built-in deaerator
- DHW pump
- Safety flow-switch, preventing operation with water circulation
malfunction in the CH system
- DHW, CH and storage tank temperature probes
- Safety limit thermostat
- Flue gas thermostat
- Integrated, automatic by-pass
- 10 liter expansion vessel
- System loading and draining taps
- Motorized switching valve
- DHW priority flow switch
Operating features
- CH electronic flame modulation with timer-controlled rising
ramp (50 seconds)
- DHW electronic flame modulation
- DHW priority function
- CH ow anti-freeze function (ON 5°C; OFF 30°C or after 15
minutes of operation)
- DHW anti-freeze function (ON 5°C; OFF 10°C or after 15 minutes
of operation)
- Storage tank anti-freeze function (ON 5°C; OFF 10°C or after 15
minutes of operation)
- Anti-legionella function
- Timer-controlled chimney-sweep function (15 minutes)
- Ignition flame propagation function
- CH maximum heat input adjusting trimmer
- Ignition heat input adjusting trimmer
- Timer-controlled room thermostat (240 seconds with CH flow
temperature >40°C)
- Heating pump post-circulation function in CH, ANTI-FREEZE and
CHIMNEY-SWEEP mode (180 seconds)
- Pump post-circulation function in DHW mode (30 s)
- Post-circulation function for CH temperature >85°C (30 seconds).
- Post-ventilation safety function (ON 95°C; OFF 90°C).
- Pump and switching valve anti-blocking function (180-seconds’
operation after 24-hours’of non operation).
- Ready for connection to a room thermostat (optional)
- Ready for operation with an external probe (optional, supplied
by the manufacturer)
- Ready for operation with an OpenTherm remote control
(optional, supplied by the manufacturer)
User interface
- Liquid crystal display showing the boiler operating status
- Mode selector: OFF, RESET, WINTER, SUMMER and ANTI-FREEZE
- CH water temperature regulator: 20-78°C (standard range) or 20-
45 °C (reduced range)
- DHW water temperature regulator: 35-57°C
- Water pressure gauge

16
2.2. Dimensions
GGas inlet
MCH flow
CDHW outlet
FCold water inlet
RCH return
RC Filling tap
SCondensate drain
RSR CH drain tap
RSS DHW storage drain tap
SV3 3-bar safety valve (CH)
SV6 6-bar safety valve (DHW)
View from above
View from below
fig. 6

17
2.3. Plumbing system
Circolatore
riscaldamento
Valvola di intercettazione
Accumulo
Sonda temperatura
Utenze
Scambiatore a piastre
Circolatore sanitario
Mandata
riscaldamento
Ritorno
riscaldamento
Flussostato
Valvola a tre vie
Valvola gas
sanitario
Sonda di temperatura
accumulo
Ventilatore modulante
Scambiatore di calore
Bruciatore
fig. 7
Heat exchanger
Burner
Modulating fan
Lock-out valve
Water flow switch
Water storage
tank
DHW pump
Plate heat exchanger
Gas valve
CH temperature
probe
3-way valve
CH flow
CH pump
CH return
Storage
tank probe
Tap
DHW probe

18
2.4. Operating data
Burner pressures must be verified after a three minute boiler operation time.
KB 24
Fuel type
Max. CH
Input
[kW]
CH
output
(80-60°C) [kW]
CH
output
(50-30°C) [kW]
DHW
output
[kW]
Gas mains
pressure
[mbar]
Diaphragm
diameter
[mm]
Flue gas
CO2
[%]
Kw min max min max min max mbar mm %
Methane Gas G20 23.7 6.5 23.1 7.3 24.8 7.3 28.0 20 7.2 8.8 ÷ 9.1
Propane Gas G31 23.7 6.5 23.1 7.3 24.8 7.3 28.0 37 5.3 9.1 ÷ 10.1
Table 4
Instantaneous DHW supply ΔT 45 K = 9.9 l/min
Instantaneous DHW supply ΔT 40 K = 11.1 l/min
Instantaneous DHW supply ΔT 35 K = 12.7 l/min
Instantaneous DHW supply ΔT 30 K = 14.8 l/min
Instantaneous DHW supply ΔT 25 K = 17.8 l/mi
Table 3
Instantaneous DHW supply ΔT 45 K = 8.9 l/min
Instantaneous DHW supply ΔT 40 K = 10.0 l/min
Instantaneous DHW supply ΔT 35 K = 11.5 l/min
Instantaneous DHW supply ΔT 30 K = 13.4 l/min
Instantaneous DHW supply ΔT 25 K = 16.1 l/min
Note: DHW supply refers to instantaneous production (Aqua Premium system disabled).
KB 24 KB 28
Equipment category - II2H3P II2H3P
Minimum CH system pressure bar 0.5 0.5
Maximum CH system pressure bar 3 3
Minimum DHW system pressure bar 0.5 0.5
Maximum DHW system pressure bar 8 8
DHW specific flow rate (Δt 30 °C) l/10’ 163 183
Electric power supply – voltage / frequency V ~ Hz 230 ~ 50 230 ~ 50
Power mains supply fuse A 2 2
Maximum power consumption W 145 145
Electric protection rating IP X4D X4D
Methane gas consumption at maximum CH input (*) m3/h 2.51 2.77
Propane gas consumption at maximum CH input kg/h 1.84 2.03
Maximum CH working temperature °C 83 83
Maximum DHW working temperature °C 62 62
Total capacity of expansion vessel l 10 10
Maximum recommended CH system capacity (**) l 200 200
Table 5
(*) Value refers to 15°C - 1013 mbar.
(**) Maximum water temperature = 83°C. Expansion vessel pressure pre-charge = 1 bar
2.5. General characteristics
KB 28
Fuel type
Max. CH
Input
[kW]
CH
output
(80-60°C) [kW]
CH
output
(50-30°C) [kW]
DHW
output
[kW]
Gas mains
pressure
[mbar]
Diaphragm
diameter
[mm]
Flue gas
CO2
[%]
Kw min max min max min max mbar mm %
Methane Gas G20 26.2 5.4 25.55 6.1 27.4 6.1 31.0 20 7.2 8.8 ÷ 9.1
Propane Gas G31
26.2 5.4 25.55 6.1 2.74 6.1 31.0 37 5.3 9.8 ÷ 10.1

19
2.6. Available head
KB 24 Pmax Pmin Reduced load
(30%)
Casing heat loss with burner on % 1.4 2.1 -
Casing heat loss with burner off % 0.2
Chimney heat loss with burner on % 2.6 2.2 -
Flue gas system mass flow rate g/s 12.4 3.1 -
Flue gas temp. – air temp °C 67 49 -
Maximum heat output efficiency rating (60/80°C) %97.5 - -
Maximum heat output efficiency rating (30/50°C) % 104.8 - -
Minimum heat output efficiency rating (60/80°C) % - 95.7 -
Minimum heat output efficiency rating (30/50°C) % - 106.9 -
30% heat output efficiency rating % - - 109.1
Efficiency rating (according to 92/42/CEE) - ★★★★
NOx emission class - 5
Table 6
KB 28 Pmax Pmin Reduced load
(30%)
Casing heat loss with burner on % 0.9 2.3 -
Casing heat loss with burner off % 0.3
Chimney heat loss with burner on % 2.5 2.2 -
Flue gas system mass flow rate g/s 13.9 3.1 -
Flue gas temp. – air temp °C 51.2 45 -
Maximum heat output efficiency rating (60/80°C) % 97.53 - -
Maximum heat output efficiency rating (30/50°C) % 105.4 - -
Minimum heat output efficiency rating (60/80°C) % - 95.5 -
Minimum heat output efficiency rating (30/50°C) % - 106.7 -
30% heat output efficiency rating % - - 108.9
Efficiency rating (according to 92/42/CEE) - ★★★★
NOx emission class - 5
Table 7
MODEL KB 28
MODEL KB 24
V1
V2
V3
Flow rate (l/h)
Head available [mbar]
Head available [mbar]
LEGEND
V1 Pump I speed (min)
V2 Pump II speed
V3 Pump III speed (max)
V1
V2 V3
Flow rate l/h
fig. 8

20
3. Instructions for the fitter
3.1. Installation standards
This is a II2H3P boiler which must be installed in compliance with the applicable laws and standards in the country of installation.
3.2. Installation
Only original accessories and spare parts supplied by the manufacturer must be used for installation
and maintenance.
If non-original accessories and spare parts are used, correct operation of the boiler cannot be guaranteed.
3.2.1. Packaging
The boiler is supplied in a sturdy cardboard box. Unwrap the boiler, then check that everything is complete and nothing is damaged.
All the packaging materials can be recycled and should be disposed of in appropriate waste collection bins. Keep the packaging out of the
reach of children as it may be a source of danger.
The manufacturer cannot be held liable for damage or injury due to non-observance of the above rules.
Contents of the box:
• kit of copper pipes for connecting the boiler to the CH and DHW system and the gas mains;
• 2 shut-o cocks: one for gas and one for cold water;
• wall hanging bracket;
• a bag containing:
a) boiler installation, use and maintenance manual
b) a wall-mounting template (fig. 9)
c) 4 screws and wall plugs for fixing the boiler to the wall.
3.2.2. Choosing where to install the boiler
There are several points to take into account when deciding where to install the boiler.
• Refer to the instructions in subsection3.2.6. Air intake/ue gas discharge system;
• Make sure the wall is strong enough to support the boiler – avoid lightweight partition walls.
• Do not install the boiler above any equipment that may affect operation (e.g. cookers generating greasy vapour or washing machines).
3.2.3. Positioning the boiler
Each boiler is provided with a paper template (fig. 9) that can be used when designing the plumbing system and prior to installation of the
boiler to position the connections to the CH system, the DHW system, the gas mains and the air intake /flue gas discharge system.
The template is made of heavy-duty paper. Fix it in position on the wall, using a spirit level. It provides all the indications required to drill the
holes for fixing the boiler to the wall, which is done using two screws and wall plugs.
The lower section of the template shows where to mark the exact spots where the fittings are to be positioned for connecting the boiler to
the gas, cold water, DHW flow, CH flow and return pipes.
The upper section shows where to mark the exact spots for positioning the air/flue gas pipes.
Since the temperature of the wall on which the boiler is fitted and the outside temperature of the coaxial air intake and
flue gas outlet pipes are less than 60°C, a minimum distance between flammable walls is not required.
For boilers with split air and flue gas pipes that run along or through flammable walls, insulation must be laid between the
wall and the flue gas outlet pipe.