Fondital TAHITI CONDENSING IST 03 C 298 - 02 User manual

IST 03 C 298 - 02
INSTALLATION,
USE AND MAINTENANCE
TAHITI CONDENSING
GB

2
Dear Customer,
Thank You for choosing and buying one of our boilers. Please read these instructions carefully in order to properly install, operate, and maintain the
equipment.
The Manufacturer recommends that Customers contact authorized qualied personnel only for maintenance and repair operations.

3
General information for tters, 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 installer 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. Following to the boiler installation, the tter is to advise the user about boiler operation and its safety
devices.
This boiler is designed for connection to a central heating system and to a hot domestic water system.
Any other use shall be considered incorrect and therefore dangerous.
The boiler must be installed by qualied personnel, in compliance with applicable laws and standards and according to the
manufacturer’s instructions given in this manual. Incorrect installation may cause injury to persons and/or animals and damage to
property. The manufacturer shall not be held liable for any such injury and/or damage.
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 relieve 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
damaged and/or faulty.
Do not obstruct the air suction openings.
Only manufacturer approved and supplied accessories or optional kits (including 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 specic waste
management sites.
Keep the packaging out of the reach of children as it may represent a source hazard.
In the event of failure and/or faulty functioning, switch o the boiler. Do not attempt to make repairs: contact qualied technicians.
Manufacturer approved and supplied parts must be used for all repairs to the boiler.
Non-observance of the above requirements may aect the safety of the boilers and endanger people, animals and property.
The manufacturer, in order to guarantee ecient and correct functioning of the equipment, recommends the boiler to be serviced
and repaired by an authorized Service Centre which is best trained for the purpose.
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.
In the event of long periods of inactivity of the boiler, disconnect it from power mains and close the gas tap.
Warning! When power mains are disconnected, boiler electronic anti-frost function will not be operative.
Should there be a risk of freezing, add anti-frost: it is not advisable to empty the system as this may result in damage; use specic
anti-frost products suitable for multi-metal heating systems.
IMPORTANT
Should you smell gas:
- do not turn on or o electric switches and do not turn on electric appliances;
- do not ignite ames and do not smoke;
- close the main gas tap;
- open doors and windows;
- contact a Service Centre, a qualied installer or the gas supply company.
Never use ames to detect gas leaks.
The boiler is designed for installation in the country indicated on the technical data plate: installation in any
other country may be source of danger for people, animals and objects.
The Manufacturer cannot be held contractually or extra-contractually liable in the event of failure to comply with the above.

4
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 qualied tter, it has been used before and is ready
to operate correctly.
If any accessories have been tted 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 specic 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.
2. Turn the master switch to ON: the display comes on and shows the function set via the boiler selector (2, g. 1).
3. If you do not wish to activate the heating function, turn the boiler selector (2, g. 1) to SUMMER. This will activate domestic hot
water (DHW) only, and the display will show the ow water temperature.
4. If you wish to activate the heating function, turn the boiler selector (2, g. 1) to WINTER. This will activate both DHW and heating,
and the display will show the ow water temperature.
5. To adjust the DHW temperature, rst turn regulator (3, g. 1) to an intermediate position (about 45 °C); then regulate it as required.
While regulating, the LCD displays the temperature setting and the tap symbol ashes.
6. To regulate the CH water temperature, rst set the regulator (4, g. 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 radiator symbol ashes.
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 g. 1) to reset for a few seconds, then back to the desired position. If the boiler
does not restart, contact an Authorised Service Centre.
Boiler selector on RESET
CH water temperature regulator
DHW temperature regulator
Boiler selector on SUMMER
Boiler selector on WINTER

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CONTENTS
Warnings page 3
General information for tters, maintenance technician and user page 4
1. User instructions page 7
1.1. Control panel page 7
1.2. LCD page 8
1.3. Boiler status - LCD activation correspondence page 9
1.4. Operating the boiler page 10
1.4.1. Switching on page 10
1.4.2. CH function page 10
1.4.3. DHW function page 10
1.4.4. ANTI-FREEZE function page 11
1.4.5. PUMP AND VALVE ANTI-SHUTDOWN function page 12
1.4.6. Operation with (optional) external probe page 12
1.4.7. Operation with (optional) remote control page 12
1.5. Boiler shutdown page 13
1.5.1. Burner shutdown page 13
1.5.2. Shutdown due to overheating page 13
1.5.3. Shutdown due air/ue gas system malfunction page 13
1.5.4. Shutdown due a water circulation malfunction page 13
1.5.5. Shutdown for fan malfunction page 14
1.5.6. Alarm due to temperature probe malfunction page 14
1.5.7. Alarm due to (optional) remote control connection malfunction page 14
1.5.8. Alarm due to (optional) external probe malfunction page 14
1.6. Maintenance page 14
1.7. Notes for the user page 14
2. Technical features and dimensions page 15
2.1. Technical features page 15
2.2. Dimensions page 16
2.3. Hydraulic layouts page 17
2.4. Operating data page 19
2.5. General characteristics page 20
3. Instructions for the tter page 21
3.1. Installation standards page 21
3.2. Installation page 21
3.2.1. Packaging page 21
3.2.2. Choosing where to install the boiler page 21
3.2.3. Positioning the boiler page 21
3.2.4. Installing the boiler page 23
3.2.5. Boiler room ventilation page 23
3.2.6. Air intake/ue gas discharge system page 24
3.2.6.1. Air/ue gas system duct conguration page 26
3.2.6.2. Ø 100/60 mm and 125/80 mm air/ue gas coaxial duct system page 27
3.2.6.3. Ø 80 mm air/ue gas split duct system page 28
3.2.7. Testing combustion eciency page 28
3.2.7.1. “Chimney sweep” function page 28
3.2.7.2. Measurement procedure page 29
3.2.8. Gas mains connection page 29
3.2.9. Hydraulic connections page 30
3.2.10. Power mains connection page 30
3.2.11. Selecting central heating output range page 31
3.2.12. Room thermostat installation (optional) page 31
3.2.13. Installation of the Open Therm remote control (optional) page 31
3.2.14. Installation of the (optional) external probe and “sliding temperature” operation page 32
3.3. Filling the system page 34
3.4. Starting the boiler page 34
3.4.1. Preliminary checks page 34
3.4.2. Switching on and o page 34
3.5. Wiring diagram page 35
3.6. Adapting to other gases and regulating the burner page 36
3.6.1. Switching from Methane to Propane page 38
3.6.2. Switching from Propane to Methane page 38
3.6.3. Burner adjustment page 38
4. Testing the boiler page 38
4.1. Preliminary checks page 39
4.2. Switching on and o page 39
5. Maintenance page 40
5.1. Maintenance schedule page 40
5.2. Combustion analysis page 40
6. Troubleshooting page 41

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PICTURE INDEX
g. 1 - Control panel page 7
g. 2 - LCD page 8
g. 3 - Fictitious room temperature regulation page 12
g. 4 - Filling tap for models KR and KC page 13
g. 5 - Filling tap for model KRB page 13
g. 6 - Dimensions page 16
g. 7 - KC model hydraulic layout page 17
g. 8 - KR model hydraulic layout page 17
g. 9 - KRB model hydraulic layout page 18
g. 10 - Installation template page 22
g. 11 - Filter installation page 23
g. 12 - Installation examples of air intake /ue gas discharge pipes page 24
g. 13 - Air intake and ue gas discharge coaxial pipe system page 27
g. 14 - Dimensions for connection to air intake and ue gas discharge coaxial pipe system page 27
g. 15 - Air intake and ue gas discharge split pipe system page 28
g. 16 - Dimensions for connection to air intake and ue gas discharge split pipe system page 28
g. 17 - Boiler casing opening page 28
g. 18 - Control panel page 29
g. 19 - Air intake and ue gas discharge tower page 29
g. 20 - Openings for combustion eciency measurement page 29
g. 21 - Gas mains connection page 29
g. 22 - Thermoregulation trimmer page 33
g. 23 - Central heating curves with external probe operation page 33
g. 24 - System head curves page 35
g. 25 - Wiring diagram page 36
g. 26 - Adaptation to other gas types page 38
g. 27 - Gas valve adjustment page 38
TABLE INDEX
Table 1 - Correlation between LED SIGNALLING – BOILER STATUS when boiler is in operation page 9
Table 2 - Correlation between LED SIGNALLING – BOILER STATUS when boiler is malfunctioning page 9
Table 3 - KC 24 model adjustment rates page 19
Table 4 - KC 28 model adjustment rates page 19
Table 5 - KC 32 model adjustment rates page 19
Table 6 - KR 24/KRB 24 model adjustment rates page 19
Table 7 - KR 28/KRB 28 model adjustment rates page 19
Table 8 - KR 32/KRB 32 model adjustment rates page 19
Table 9 - KC/KB/KRB model general specications page 20
Table 10 - KC 24/KR 24/KRB 24 model combustion rates page 20
Table 11 - KC 28/KR 28/KRB 28 model combustion rates page 20
Table 12 - KC 32/KR 32/KRB 32 model combustion rates page 20
Table 13 - Burner re-ignition temperatures page 31
Table 14 - Limits to be set for TSP parameters and default values in relation to boiler type (TSP0) page 32
Table 15 - TSP chart of parameters which can be displayed (they cannot be adjusted via remote control) page 32
Table 16 - Correlation“temperature – nominal resistance”of temperature probes page 37
Table 17 - CO2rates page 38

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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 g. 2).
2. Boiler function 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 (KC model, KR + optional external water heater and KRB
+optional external water heater).
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 and to set the DHW temperature in the range 35-57°C.
For KR boiler with an external (optional) water heater, this regulator also activates/deactivates the heater.
For boilers model KR and KRB connected to an (optional) water heater this regulator also enables/disables the water heater.
WARNING
In KC model, a special adjusting device is installed, which limits domestic hot water ow rate to 13 liter per minute (KC 24), 14 liter per
minute (KC 28) and to 16 liter per minute (KC 32).
Domestic hot water temperature supplied, depends on no. 3 adjusting device, on the quantity requested by the user and on water
mains supply temperature.
4. CH water temperature regulator
This is used to select the temperature of the water in the heating system in the range 20 °C to 45 or 78°C (depending on the selected temperature
range).
5. Water pressure gauge
This shows the pressure of the water in the heating system.
g. 1
1 2 3 4 5

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1.2. LCD
a. DHW indicator
This comes on when the boiler is in DHW mode.
It ashes when the DHW temperature is being regulated via regulator 3(g. 1).
b. Water heater on indicator
This indicator comes on when the water heater (optiona) is activated via regulator 3(g. 1).
c. Alphanumeric indicator
This shows the following:
- CH ow water 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 ashes when the CH temperature is being regulated via regulator 4(g. 1).
e. Boiler shutdown indicator
This comes on when there is a malfunction that cannot be reset via the boiler funtion selector (2, g. 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, g. 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 ame is present.
i. Chimney-sweep function indicator (for tter only)
This ashes when the chimney-sweep function is activated.
The ow water temperature and the number of fan rounds are shown alternatively (in this case, symbol mis also shown)
i. Thermoregulation indicator (for tter only)
This comes on when the thermoregulation curve is set.
l. Fictitious room temperature indicator
When an external probe is installed, this indicator ashes when the ctitious room temperature is set via regulator 4.
m. Number of fan rounds (for tter only)
When the chimney sweep function is activated, symbol hashes and ow water temperature and number of fan rounds are shown alternatively (in
this case, the correspondent symbol is also shown).
g. 2
a b c d
e
f g h i l
m

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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 ow water temperature is displayed
Boiler selector on SUMMER or WINTER
DHW system enabled (KC model only)
The ow water temperature is displayed
Boiler selector on WINTER
CH function active
The ow water temperature is displayed
Boiler selector on SUMMER or WINTER
External (optional) water heater enabled, no function active
The ow water temperature is displayed
(Only for KR and KRB models connected to an optional water heater)
Table 1 - BOILER STATUS - LCD visualisation correspondence (normal operation)
Malfunction
Boiler not powered on
Boiler shutdown due to ame absence
Boiler shutdown due to safety thermostat activation
Boiler shutdown due to ue gas thermostat activation
CH probe failure
DHW probe failure
KC model only
Water heater probe fault
(Only for KR and KRB models connected to an optional water heater with NTC probe)
Shutdown due to a water circulation malfunction in CH system or minimum pressure gauge
(pump ON – main ow switch OPEN)
Shutdown due to a water circulation malfunction in CH system
(pump OFF – main ow switch CLOSE)
Fan failure
Remote control (optional) connection failure
External probe (optional) failure
Table 2 - BOILER STATUS - LCD visualisation correspondence (malfunction)

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1.4. Operating the boiler
1.4.1. Switching on
The following procedure is to be implemented only after the boiler is installed and tested by a qualied tter.
• Open the gas stop cock;
• turn ON the power switch external to the boiler; the LCD shows and indicates the active function (see tables 1 and 2);
• select boiler operation mode via no. 2selector (g. 1): OFF/SUMMER/WINTER/ANTI-FREEZE;
• set desired CH temperature (see par. 1.4.2.);
• Set desired DHW temperature (see par. 1.4.3.);
• Set desired room temperature by means of the room thermostat in the premises (when available).
WARNING
Should the boiler be left inactive for a long time, particularly when boiler is propane-red, ignition might be dicult.
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 diculties and shut down once or twice.
Resume boiler operation by turning no. 2 knob to the reset position for two seconds and back to the desired position.
1.4.2. CH function
Set desired CH water temperature via no. 4knob (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 tter or an authorized Service Centre (see 3.2.11. paragraph).
During temperature setting, the CH symbol on the LCD ashes and the CH setting is displayed.
When the CH system requests heat, the LCD shows the (xed) 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 o 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 (see 3.2.11. paragraph), waiting time procedure is aborted and boiler re-
ignited.
1.4.3. DHW function
Set desired domestic hot water temperature via no. 3knob (g.1).
Domestic hot water supply is activated in KC model and KR, KRB model equipped with an external heater (optional equipment).
Such function always has priority over CH water supply.
In KC model, set desired domestic hot water temperature via no. 3knob (g.1). It can be adjusted within a 35°C to 57°C range (from full counter-
clockwise position to full clockwise position).
During temperature setting, the DHW symbol on the LCD ashes and the DHW setting is displayed.
In KR and KRB model equipped with external heater (optional equipment), DHW production through the external
heater may be activated/deactivated via no. 3knob.
If you turn knob 3fully anticlockwise, the water heater-active symbol is displayed. Now turn knob 3until a
temperature of at least 40°C is displayed. To switch o the water heater, turn knob 3fully anticlockwise again until
the symbol disappears and then back to a position showing a temperature of at least 40 °C.
For models KR and KRB with an (optional) external water heater with an NTC probe (10 kΩ @ β=3435; refer to the water heater specications),
the temperature setting range is 35-57°C (from the counter-clockwise limit position to full clockwise position of regulation knob 3). During
temperature setting, the DHW symbol on the LCD ashes and the DHW setting is displayed.
For models KR and KRB with an (optional) external water heater with thermostat probe, the desired HDW
temperature must be set on the water heater (refer to the attached instructions). Regulation knob 3has no eect
on this conguration, except for water heater activation/deactivation as described above.
When the DHW system requests hot water, the LCD shows the (xed) DHW symbol and the temperature of the
DHW water.
The burner symbol only shows while the burner is operating.

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WARNING
In KC model, a special adjusting device is installed, which limits domestic hot water ow rate to 13 liter per minute (KC 24), 14 liter per
minute (for model KC 28) and 16 liter per minute (KC 32).
Domestic hot water temperature supplied depends on no. 3 adjusting device, on the quantity requested by the user and on water
mains supply temperature, according to the following formula:
K
l = DHW liter per min. = --------
ΔT
K represents:
- 401 in KC 24 model
- 444 in KC 28 model
- 507 in KC 32 model
Δt = DHW temperature – water mains supply temperature
For instance, with model KC 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:
I = 401 / 30 = 13.4 [litres per minute - mixed water to the tap]
In models KR and KRB with optional external heater, the quantity of DHW available depends on the heater.
In models KR and KRB with optional external heater, the anti-legionellose function is activated, which consists of heating the water inside the
heater to a temperature of 65 °C for 30 minutes, without taking into account any of the other settings.
1.4.4. ANTI-FREEZE function
This boiler is tted with an anti-freeze protection system, which works when the following functions are activated: SUMMER, WINTER and ANTI-
FREEZE.
The anti-freeze function only protects the boiler, not the whole heating system.
The heating system must be protected using a room thermostat, although this is disabled when the selector is set
to the ANTI-FREEZE or OFF mode.
Therefore, if you want to protect both the boiler and the system, turn to WINTER mode on selector 2.
When the heating water temperature sensor detects a water temperature of 5°C, the boiler switches on and stays on at its minimum thermal power
until the temperature reaches 30°C or 15 minutes have elapsed. The pump continues to operate even if the boiler shuts down.
In models KC, anti-freeze function also protects the DHW circuit.
When the DHW temperature sensor detects a temperature of 5°C, the boiler switches on and stays on at its minimum thermal power until the
temperature reaches 10°C or 15 minutes have elapsed (the deviating valve is in the DHW position). The pump continues to operate even if the
boiler shuts down.
In models KR and KRB with optional external heater for DHW production tted with a NTC temperature sensor (10 kΩ @ ß=3435; please refer to the
heater technical characteristics), the anti-freeze function also protects the heater.
When the heater temperature sensor detects a temperature of 5°C, the boiler switches on and stays on at its minimum thermal power until the
temperature reaches 10°C or 15 minutes have elapsed (the deviating valve is in the DHW position). The pump continues to operate even if the
boiler shuts down.
In models KR and KRB with optional external heater for DHW production tted with a thermostat-type temperature sensor, the anti-freeze function
DOES NOT protect the water heater.
Water heater protection can be ensured by setting the boiler to SUMMER or WINTER (via no. 2knob), activating the heater (via no. 3knob),
as described above, and setting a heater thermostat temperature higher than 0 °C.
The CH system can be protected eectively against freezing by means of specic anti-freeze additives suitable for use in multi-metal systems.
Do not use car engine anti-freeze products, and periodically check the eectiveness of the anti-freeze product.

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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,
- the boiler is still connected to the mains supply,
the pump and the switching valve activate briey every 24 hours to keep them ecient.
1.4.6. Operation with an (optional) external probe
The boiler can be connected to an (optional, can be supplied by the Producer) 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, regulator 4(g. 1) looses its heating water temperature function and
becomes a ctitious room temperature regulator (g. 3) for the temperature desired in the areas to be
heated.
During temperature setting, the ctitious room temperature symbol ashes
and the temperature setting is displayed.
Regulator 4in the fully anticlockwise position corresponds to a ctitious room 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.
For details on how to connect the external probe, refer to subsection 3.2.14.
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.
1.4.7. Operation with (optional) remote control
The boiler can be linked to an (optional, supplied by the Manufacturer) remote control, which can be used for setting numerous parameters:
- boiler status
- room temperature
- CH system water temperature
- DHW system water temperature
- CH system or external heater (optional) activation times
- boiler diagnostics display
- boiler reset
and others.
For instructions on how to connect the remote control, refer to par. 3.2.13. and to its own instruction booklet.
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.
g. 3
15 35
32
25
18

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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 ame, the burner shutdown symbol is displayed and code E01 ashes.
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;
• if the gas supply is normal, turn selector 2to the reset position for a few seconds, then back to the desired
position. If after three attempts the burner still fails to ignite, contact an Authorised Service Centre or a qualied service engineer.
If the burner shuts down frequently, there is a recurring malfunction, so contact an Authorised Service Centre or a qualied 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 ashes.
Contact an Authorised Service Centre or a qualied service engineer.
1.5.3. Shutdown due to air/ue gas system malfunction
If the air/ue gas system malfunctions, the boiler shuts down. The burner shutdown symbol is displayed and
code E03 (ue gas thermostat).
Contact an Authorised Service Centre or a qualied service engineer.
1.5.4. Shutdown due to a water circulation malfunction
If there is a malfunction in water circulation in the heating system, the boiler shuts down. The boiler shutdown symbol is displayed and code
E10 or E26 ash, according to the malfunction.
1. With code E10 ashing there can be two dierent situations:
a) the pressure gauge (5, g. 1) shows a pressure lower than 1 bar
Proceed as follows to restore the correct water pressure:
• Turn the lling tap (g. 4) 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 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 an Authorised Service Centre or a qualied service engineer.
Make sure you close the tap carefully after lling.
If you do not, when the pressure increases, the safety valve may activate and discharge water.
b) the pressure gauge (5, pic 1) shows a pressure of 1-1.3 bar
Contact an Authorised Service Centre or a qualied service engineer.
2. With ashing code E26, contact an Authorised Service Centre or a qualied service engineer.
g. 4 Filling tap
KC and KR
g. 5 Filling tap
KRB

14
1.5.5. Shutdown for fan malfunction
The fan work is constantly monitored and in case of malfunction it goes o; the boiler shutdown symbol is
displayed and code E17 ashes.
This mode is maintained until the fan recovers normal working parameters.
If the boiler should not start and remain in this mode, contact an Authorised Service Centre or a qualied 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
ash:
• E05, CH probe: the boiler does not work;
• E06, DHW probe (KC model only): the boiler only operates in CH mode, not DHW mode;
• E12, storage probe (KR/KRB model only with external optional water heater tted with NTC 10 kΩ @ß=3435 temperature probe); the boiler
operates in CH while DHW mode is disabled.
Contact an Authorised Service Centre or a qualied service engineer.
1.5.7. 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 ashes.
The boiler will continue to operate according to the settings on the control panel (g. 1) and ignore the remote
control settings.
Contact an Authorised Service Centre or a qualied service engineer.
1.5.8. Alarm due to (optional) external probe malfunction
If the (optional) external temperature probe malfunctions, the boiler shutdown symbol is displayed and code
E23 ashes.
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(g. 1), which in this case loses its function as a
ctitious room temperature regulator (see 1.4.6.).
Contact an Authorised Service Centre or a qualied 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 eciently, without harming the environment, and in complete safety.
Maintenance and repairs must be performed by qualied personnel.
The user is strongly advised to have the boiler serviced and repaired by one of the Manufacturer’s fully qualied and authorised
Service Centres.
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 qualied 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 o 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 qualied personnel.
Pump failure can be avoided by adding to the water lming 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:
KC: condensing boiler with sealed chamber and forced draught, supplying CH water and instant DHW;
KR: condensing boiler with sealed chamber and forced draught, supplying CH water;
KRB: condensing boiler, forced draught and sealed chamber, with production of hot water for CH system; equipped with a deviation three-way
valve allowing for connection to an (Optional) water heater.
Both models are available in the following heat outputs:
KC 24, KR 24 and KRB 24 = 23.7 kW
KC 28, KR 28 and KRB 28 = 26.2 kW
KC 32, KR 32 and KRB 32 = 31.4 kW
Both models are equipped with electronic ignition and ionization ame sensing device.
The boilers meet local applicable Directives enforced in the country of destination, which is stated on their data plate.
Boiler installation in a dierent country from specied may endanger people, animals and objects.
The main technical characteristics of the boilers are listed below:
Manufacturing characteristics
- IPX4D electrically protected control panel
- Integrated, modulating electronic safety board
- Electronic ignition via separated igniter and ionization ame
detection
- Stainless steel, fully pre-mixed burner
- Mono-thermal, high eciency, composite and stainless steel heat
exchanger with air purging device
- Twin shutter, modulating gas valve with constant air/gas ratio
- Modulating, electronically managed ue gas discharge fan
- Three-speed pump with air purging device
- Safety ow-switch, preventing operation with water circulation
malfunction in the CH system
- CH temperature probe (KC, KR and KRB) and DHW (KC)
- Safety limit thermostat
- Flue gas thermostats
- Integrated, automatic by-pass
- 10 liter expansion vessel
- System loading and draining taps
- Stainless steel plate DHW heat exchanger (KC)
- Motorized deviating valve (KC and KRB)
- DHW priority ow switch (KC)
- DHW ow limiting device; 13 liter/min (KC 24), 14 liter/min (KC 28),16
liter/min (KC 32)
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
Operating features
• CH electronic ame modulation with timer-controlled rising ramp (50
seconds)
• DHW electronic ame modulation (KC, KR with optional external
water heater and KRB with optional external water heater)
• DHW priority function (KC, KR with optional external water heater and
KR with optional external water heater)
• CH anti-freeze function (ON 5°C; OFF 30°C or after 15 minutes of
operation if CH temperature > 5 °C)
• DHW anti-freeze function (KC only), (ON 5°C; OFF 10°C or after 15
minutes of operation if DHW temperature > 5 °C)
• Water heater anti-freeze function (KR models + optional water heater
with NTC probe and KRB models + optional water heater with NTC
probe): ON 5°C; OFF 10°C or after 15 minutes of operation if water
temperature in the heater > 5° C)
• Timer-controlled chimney-sweep function (15 minutes)
• Anti-legionella function (KR +optional external water heater and KRB
+optional external water heater)
• CH maximum heat input adjusting trimmer
• Ignition heat input adjusting trimmer
• Possibility to select the heating range: standard or reduced
• Ignition ame propagation function
• Timer-controlled room thermostat (240 seconds with standard range,
120 seconds with reduced range)
• Heating pump post-circulation function in CH, ANTI-FREEZE and
CHIMNEY-SWEEP mode (180 seconds)
• Heating pump post-circulation function in DHW mode (KC, KR with
optional external heater and KRB with optional external heater): 30
seconds
• Post-circulation function for heating temperature >85°C (30 seconds)
• Post-ventilation function after working: 10 seconds
• Post-ventilation safety function (ON 95°C;)
• Anti-blocking function (KC, KR and KRB) and switching valve (KC and
KRB) : 180 seconds operation every 24 hours of boiler inactivity
• 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)
• Ready for operation with a module for dierent temperature zones

16
g. 6
SI
RC
RS
SV
2.2. Dimensions
S Condensate drain
F Water mains intake (KC and KR)
RB Secondary return from the boiler (only KRB model)
GGas intake
SI Inspection trap plug
MCH system ow
C DHW ow (KC model only)
SV 3-bar safety valve drain cock
RC Filling tap
R CH system return
RS Drain cock
MB Secondary ow to the boiler (only KRB model)
71
43 56 98 75 98 80
138
177
46
GM
MB RB
RC
R
SV
SI
View from the bottom of models KC and KR
View from the bottom of model KRB
In model KRB the connection to the cold water mains must be made through the 1/8’’ connection on the loading tap (shown with a
broken line in the gure above).
139,5
135 148
90
90 77
325
750
450
138
177
56 98 75 98 80
71
43
46
GMFR
S
C

17
g. 7
g. 8
1. Condensate drain siphon
2. Modulating gas valve
3. Safety thermostat
4. CH temperature probe
5. Modulating fan
6. Primary uid ow meter
7. Primary condensing exchanger
8. Ignition electrode
9. Air purging device
10. Combustion air intake system
11. Flue gas discharge system
12. Flue gas analysis ports
13. Flue gas thermostat on discharge duct
14. Flue gas thermostat on exchanger
15. Flame sensing electrode
16. Expansion vessel
17. Fan management probe
18. Air purging device
19. Pump
20. 3 bar safety valve
21. Unloading tap
22. Minimum pressure switch
23. Flow limiting device
24. Loading tap
25. Domestic cold water ow meter with lter
26. Secondary plate exchanger
27. DHW probe
28. Automatic by-pass
29. Motorized 3-way valve
S Condensate drain
G Gas intake
M CH system ow
C DHW ow
F Water mains intake
R CH system return
1. Condensate drain siphon
2. Modulating gas valve
3. Safety thermostat
4. CH temperature probe
5. Modulating fan
6. Primary uid ow meter
7. Primary condensing exchanger
8. Ignition electrode
9. Air purging device
10. Combustion air intake system
11. Flue gas discharge system
12. Flue gas analysis ports
13. Flue gas thermostat on discharge duct
14. Flue gas thermostat on exchanger
15. Flame sensing electrode
16. Expansion vessel
17. Fan management probe
18. Air purging device
19. Pump
20. 3 bar safety valve
21. Unloading tap
22. Minimum pressure switch
23. Loading tap
24. Automatic by-pass
SCondensate drain
GGas intake
MCH system ow
FWater mains intake
R CH system return
Model KC
Model KR
2.3. Hydraulic layouts
11
GMSCFR
10
9
8
7
6
5
4
3
2
1
28 27 26 25 24
12
13
14
15
16
17
18
19
20
21
22
23
11
10
9
8
7
6
5
4
3
2
1
12
13
14
15
16
17
18
19
20
21
22
23
GMSFR

18
1. Condensate drain siphon
2. Modulating gas valve
3. Safety thermostat
4. CH temperature probe
5. Modulating fan
6. Primary uid ow meter
7. Primary condensing exchanger
8. Ignition electrode
9. Air purging device
10. Combustion air intake system
11. Flue gas discharge system
12. Flue gas analysis ports
13. Flue gas thermostat on discharge duct
14. Flue gas thermostat on exchanger
15. Flame sensing electrode
16. Expansion vessel
17. Fan management probe
18. Air purging device
19. Pump
20. 3 bar safety valve
21. Unloading tap
22. Minimum pressure switch
23. Automatic by-pass
24. Motorized 3-way valve
S Condensate drain
G Gas intake
M CH system ow
MB Secondary ow to the boiler
RB Secondary return from the boiler
R CH system return
g. 9
11
GMSMBRBR
10
9
8
7
5
4
3
2
1
24 23
12
13
14
15
16
17
18
19
20
21
22
6

19
2.4. Operating data
Burner pressures must be veried after a three minute boiler operation time
KC 24
Function
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
[%]
min max min max min max
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 9.8 ÷ 10.1
Table 3 – KC 24 model adjustment rates
Hot water supply ΔT 45°C = 8.9 l/min
Hot water supply ΔT 40°C = 10 l/min
Hot water supply ΔT 35°C = 11.5 l/min
Hot water supply ΔT 30°C = 13.4 l/min *
Hot water supply ΔT 25°C = 16.1 l/min *
*Note: mixed water to the tap
KC 28
Function
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
[%]
min max min max min max
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 27.4 6.1 31.0 37 5.3 9.8 ÷ 10.1
Table 4 - KC 28 model adjustment rates
Hot water supply ΔT 45°C = 9.9 l/min
Hot water supply ΔT 40°C = 11.1 l/min
Hot water supply ΔT 35°C = 12.7 l/min
Hot water supply ΔT 30°C = 14.8 l/min *
Hot water supply ΔT 25°C = 17.8 l/min *
*Note: mixed water to the tap
KC 32
Function
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
[%]
min max min max min max
Methane Gas G20 31.4 8.7 30.63 9.6 33.2 9.6 35.4 20 8.4 8.8 ÷ 9.1
Propane Gas G31
31.4 8.7 30.63 9.6 33.2 9.6 35.4 37 6.0 9.8 ÷ 10.1
Table 5 - KC 32 model adjustment rates
Hot water supply ΔT 45°C = 11.3 l/min
Hot water supply ΔT 40°C = 12.7 l/min
Hot water supply ΔT 35°C = 14.5 l/min
Hot water supply ΔT 30°C = 16.9 l/min *
Hot water supply ΔT 25°C = 20.3 l/min *
*Note: mixed water to the tap
KR 24/KRB 24
Function
Max. CH
input
(kW)
CH
output
(80-60°C)
[kW]
CH
output
(50-30°C)
[kW]
Gas mains
pressure
[mbar]
Diaphragm diameter
[mm]
Flue gas
CO2
[%]
min max min max
Methane Gas G20 23.7 6.5 23.1 7.3 24.8 20 7.2 8.8 ÷ 9.1
Propane Gas G31
23.7 6.5 23.1 7.3 24.8 37 5.3 9.8 ÷ 10.1
Table 6 - KR 24/KRB 24 model adjustment rates
KR28/KRB 28
Function
Max. CH
input
(kW)
CH
output
(80-60°C)
[kW]
CH
output
(50-30°C)
[kW]
Gas mains
pressure
[mbar]
Diaphragm diameter
[mm]
Flue gas
CO2
[%]
min max min max
Methane Gas G20 26.2 5.4 25.5 6.1 27.4 20 7.2 8.8 ÷ 9.1
Propane Gas G31
26.2 5.4 25.5 6.1 27.4 37 5.3 9.8 ÷ 10.1
Table 7 - KR 28/KRB 32 model adjustment rates
KR 32/KRB 32
Function
Max. CH
input
(kW)
CH
output
(80-60°C)
[kW]
CH
output
(50-30°C)
[kW]
Gas mains
pressure
[mbar]
Diaphragm diameter
[mm]
Flue gas
CO2
[%]
min max min max
Methane Gas G20 31.4 8.7 30.63 9.6 33.2 20 8.4 8.8 ÷ 9.1
Propane Gas G31
31.4 8.7 30.63 9.6 33.2 37 6.0 9.8 ÷ 10.1
Table 8 - KR 32/KRB 32 model adjustment rates

20
2.5. General characteristics
Models KC/KR/KRB 24 28 32
Equipment category - II2H3P II2H3P II2H3P
Minimum CH system pressure bar 0.5 0.5 0.5
Maximum CH system pressure bar 3 3 3
Minimum DHW system pressure bar 0.5 0.5 0.5
Maximum DHW system pressure bar 8 8 8
DHW specic ow rate (Δt 30 °C) l/min 13.5 14.4 16.5
Electric power supply – voltage / frequency V - Hz 230 - 50 230 - 50 230 - 50
Power mains supply fuse A 2 2 2
Maximum power consumption W 145 145 145
Electric protection rating IP X4D X4D X4D
Net weight kg 38.5 39.2 40.0
Methane gas consumption at maximum CH input (*) m3/h 2.51 2.77 3.32
Propane gas consumption at maximum CH input kg/h 1.84 2.03 2.44
Maximum CH working temperature °C 83 83 83
Maximum DHW working temperature °C 62 62 62
Total capacity of expansion vessel l 10 10 10
Maximum recommended CH system capacity (**) l 200 200 200
Table 9 - KC/KR/KRB model general specications
(*) Value referred to 15°C - 1013 mbar
(**) Maximum water temperature 83°C, expansion vessel pressure 1 bar
KC 24/KR 24/KRB 24 Max. heat output Min. heat output 30% heat output
Casing heat loss with burner on % 1.4 2.1 -
Casing heat loss with burner o % 0.2
Chimney heat loss with burner on % 2.6 2.2 -
Flue gas system mass ow rate g/s 12.4 3.1 -
Flue gas temp. – air temp °C 67 49 -
Maximum heat output eciency rating (60/80°C) % 97.5 - -
Maximum heat output eciency rating (30/50°C) % 104.8 - -
Minimum heat output eciency rating (60/80°C) % - 95.7 -
Minimum heat output eciency rating (30/50°C) % - 106.9 -
30% heat output eciency rating % - - 109.1
Eciency rating (according to 92/42/CEE) -
NOxemission class - 5
Table 10 - KC 24/KR 24/KRB 24 model combustion rates
KC 28/KR 28/KRB 28 Max. heat output Min. heat output 30% heat output
Casing heat loss with burner on % 0.9 2.3 -
Casing heat loss with burner o % 0.3
Chimney heat loss with burner on % 2.5 2.2 -
Flue gas system mass ow rate g/s 13.9 3.1 -
Flue gas temp. – air temp °C 51.2 45 -
Maximum heat output eciency rating (60/80°C) % 97.53 - -
Maximum heat output eciency rating (30/50°C) % 105.4 - -
Minimum heat output eciency rating (60/80°C) % - 95.5 -
Minimum heat output eciency rating (30/50°C) % - 106.7 -
30% heat output eciency rating % - - 108.9
Eciency rating (according to 92/42/CEE) -
NOxemission class - 5
Table 11- KC 28/KR 28/KRB 28 model combustion rates
KC 32/KR 32/KRB 32 Max. heat output Min. heat output 30% heat output
Casing heat loss with burner on % 0.6 1.6 -
Casing heat loss with burner o % 0.2
Chimney heat loss with burner on % 2.4 2.1 -
Flue gas system mass ow rate g/s 15.7 4.1 -
Flue gas temp. – air temp °C 54 51 -
Maximum heat output eciency rating (60/80°C) % 97.57 - -
Maximum heat output eciency rating (30/50°C) % 105.4 - -
Minimum heat output eciency rating (60/80°C) % - 96.3 -
Minimum heat output eciency rating (30/50°C) % - 106.3 -
30% heat output eciency rating % - - 108.7
Eciency rating (according to 92/42/CEE) -
NOxemission class - 5
Table 12 - KC 32/KR 32/KRB 32 model combustion rates