Fondital TAHITI CONDENSING KC24 Quick start guide

IST 03 C 234 - 01
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.

3
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 in-
staller 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 fitter is to advise the user about boiler operation and its safety devices.
This boiler must be used for the purposes for which it has been intended.
Any other use shall be considered incorrect and therefore dangerous.
The boiler must be installed by qualified personnel, in compliance with applicable laws and standards and according to the manufac-
turer’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 specific waste manage-
ment 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 off the boiler. Do not attempt to make repairs: contact qualified technicians.
Manufacturer approved and supplied parts must be used for all repairs to the boiler.
Non-observance of the above requirements may affect the safety of the boilers and endanger people, animals and property.
The manufacturer, in order to guarantee efficient 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 is to be performed according to the schedule indicated in the relevant section of this manual.
Appropriate boiler maintenance ensures efficient operation, environment preservation, and safety for people, animals and
objects.
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 specific anti-
frost products suitable for multi-metal heating systems.
IMPORTANT
Should you smell gas:
- do not turn on or off electric switches and do not turn on electric appliances;
- do not ignite flames and do not smoke;
- close the main gas tap;
- open doors and windows;
- contact a Service Centre, a qualified installer or the gas supply company.
Never use flames 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.

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CONTENTS
Warnings page 2
General information for the installer, maintenance technician and user page 3
1. Instructions for the User page 6
1.1. Control panel page 6
1.2. Operating the boiler page 8
1.2.1. Switching on page 8
1.2.2. Operation page 8
1.2.3. External temperature probe operation (optional equipment) page 9
1.3. Boiler shutdown page
10
1.3.1. Burner shut-down page
10
1.3.2. Shut-down due to overheating page
10
1.3.3. Shut-down due to incorrect fluid circulation page
10
1.3.4. Shut-down due to inadequate air/flue gas draught (flue gas shutdown) page
11
1.3.5. Shut-down due to fan malfunction page
11
1.3.6. Flow alarm page
11
1.3.7. Alarm due to failure of temperature probes page
11
1.3.8. Alarm due to remote control malfunction page
11
1.4. Maintenance page
11
1.5. Notes for the user page
11
2. Technical characteristics and dimensions page
12
2.1. Technical characteristics page
12
2.2. Dimensions page
14
2.3. Hydraulic layouts page
15
2.4. Operating data page
16
2.5. General characteristics page
17
3. Instructions for the fitter page
19
3.1. Installation standards page
19
3.2. Installation page
19
3.2.1. Packaging page
19
3.2.2. Choosing where to install the boiler page
19
3.2.3. Positioning the boiler page
20
3.2.4. Installing the boiler page
20
3.2.5. Boiler room ventilation page
21
3.2.6. Air/flue gas system page
21
3.2.6.1. Air/flue gas system duct configuration page
22
3.2.6.2. 100/60 mm and 125/80 mm air/flue gas coaxial duct system page
23
3.2.6.3. 80 mm air/flue gas split duct system page
24
3.2.7. Testing combustion efficiency page
24
3.2.7.1. “Chimney sweep” function page
24
3.2.7.2. Measurements page
25
3.2.8. Gas main connection page
26
3.2.9. Hydraulic connections page
26
3.2.10. Power main connection page
27
3.2.11. Selecting central heating output range page
27
3.2.12. Room thermostat connection (optional equipment) page
28
3.2.13. Open Therm remote control installation and operation procedure (optional equipment) page
28
3.2.14. External temperature probe installation (optional equipment) and “sliding temperature” operation page
29
3.2.15. Phone operation device installation (optional equipment) page
30
3.3. Loading the system page
30
3.4. Starting the boiler page
31
3.4.1. Preliminary checks page
31
3.4.2. Switching on and switching off page
31
3.5. Electric diagram page
32
3.6. Adaptation to other gases and burner adjustment page
33
4. Testing the boiler page
35
4.1. Preliminary checks page
35
4.2. Switching on and switching off page
35
5. Maintenance page
35
6. Troubleshooting page 36

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PICTURE INDEX
pic. 1 - Control panel page 6
pic. 2 - Loading tap page 10
pic. 3 - Dimensions page 14
pic. 4 - KC model hydraulic layout page 15
pic. 5 - KR model hydraulic layout page 15
pic. 6 - Installation template page 20
pic. 7 - Installation of the seal with filter page 21
pic. 8 - Installation examples of air intake /flue gas discharge pipes page 21
pic. 9 - Air intake and flue gas discharge coaxial pipe system page 23
pic. 10 - Dimensions for connection to air intake and flue gas discharge coaxial pipe system page 23
pic. 11 - Air intake and flue gas discharge split pipe system page 24
pic. 12 - Dimensions for connection to air intake and flue gas discharge split pipe system page 24
pic. 13 - “Chimney sweep” function page 25
pic. 14 - Air intake and flue gas discharge tower page 25
pic. 15 - Openings for combustion efficiency measurement page 25
pic. 16 - Gas mains connection page 26
pic. 17 - Open Therm remote control installation page 28
pic. 18 - Correlation between P6 trimmer position and thermoregulation curves page 29
pic. 19 - Central heating curves in external probe operation page 29
pic. 20 - System head curves page 31
pic. 21 - Electric layout page 32
pic. 22 - Adaptation to other gas types page 34
pic. 23 - Gas valve adjustment page 34
CHART INDEX
No. 1 chart - Correlation between LED SIGNALLING – BOILER STATUS when boiler is in operation page 7
No. 2 chart - Correlation between LED SIGNALLING – BOILER STATUS when boiler is malfunctioning page 7
No. 3 chart - KC 24 model adjustment rates page 16
No. 4 chart - KC 32 model adjustment rates page 16
No. 5 chart - KR 24 model adjustment rates page 16
No. 6 chart - KR 32 model adjustment rates page 16
No. 7 chart - KC model general specifications page 17
No. 8 chart - KC 24 model combustion rates page 17
No. 9 chart - KC 32 model combustion rates page 17
No. 10 chart - KR model general specifications page 18
No. 11 chart - KR 24 model combustion rates page 18
No. 12 chart - KR 32 model combustion rates page 18
No. 13 chart - Burner re-ignition temperatures page 27
No. 14 chart - Limits to be set for TSP parameters and default values in relation to boiler type (TSP0) page 28
No. 15 chart - TSP chart of parameters which can be displayed (they cannot be adjusted via remote control) page 28
No. 16 chart - Correlation “temperature – nominal resistance” of temperature probes page 33
No. 17 chart - CO2 rates page 34

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1. Power LED (green)
The LED indicates that electric power is being supplied to the
boiler.
2. Signal LED (red)
When the LED is on and fixed, it signals central water temperature
is in the range between 26°C and 35°C.
When the LED is on and blinking, it signals an operation malfunc-
tion (see no. 2 chart on page 7).
3. Signal LED (red)
When the LED is on and fixed, it signals central water temperature
is in the range between 36°C and 45°C.
When the LED is on and blinking, it signals an operation malfunc-
tion (see no. 2 chart on page 7).
4. Signal LED (red)
When the LED is on and fixed, it signals central water temperature
is in the range between 46°C and 55°C.
When the LED is on and blinking, it signals an operation malfunc-
tion (see no. 2 chart on page 7).
5. Signal LED (red)
When the LED is on and fixed, it signals central water temperature
is in the range between 56°C and 65°C.
When the LED is on and blinking, it signals an operation malfunc-
tion (see no. 2 chart on page 7).
6. Signal LED (red)
When the LED is on and fixed, it signals central water temperature
is in the range between 66°C and 75°C.
When the LED is on and blinking, it signals an operation malfunc-
tion (see no. 2 chart on page 7).
7. Signal LED (red)
When the LED is on and fixed, it signals central water temperature
is in the range between 76°C and 85°C.
When the LED is on and blinking, it signals an operation malfunc-
tion (see no. 2 chart on page 7).
8. Signal LED (yellow)
When the LED is on and fixed, it signals flame presence on burner.
When the LED is on and blinking, it signals an operation malfunc-
tion (see no. 2 chart on page 7).
9. Boiler operation mode selector
When the selector is set to OFF, the boiler is in stand-by.
When the selector is positioned to WINTER , the boiler is ready
to operate both in central heating and domestic hot water supply
modes (in KR models, domestic hot water supply mode is activa-
ted only when the boiler is connected to an external cylinder).
When the selector is positioned to SUMMER , the boiler is rea-
dy to operate in domestic hot water supply mode (in KR models,
domestic hot water supply mode is activated only when the boiler
is connected to an external cylinder).
When the selector is positioned to ANTI-FROST only the anti-
frost function is active.
When the selector is positioned to RESET , the boiler is re-acti-
vated after a shutdown.
10. Domestic hot water temperature adjusting knob
The knob is adjusts domestic hot water temperature between a
minimum of 35°C and a maximum of 57°C.
WARNING
In KC model, a special adjusting device is installed, which
limits domestic hot water flow rate to 13 liter per minute (KC
24), and to 16 liter per minute (KC 32). Domestic hot water
temperature supplied, depends on no. 10 adjusting device, on
the quantity requested by the user and on water mains supply
temperature.
11. CH temperature adjustment
The knob is adjusts central heating water temperature between a
minimum of 20°C and a maximum of 78°C.
12. Water pressure gauge
Water pressure gauge indicates water pressure in the heating
system.
1. Instructions for the user
1.1. Control panel
pic. 1 - Control panel

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CORRELATION BETWEEN LED SIGNALLING – BOILER STATUS
Normal boiler operation LED 1 LED 2 LED 3 LED 4 LED 5 LED 6 LED 7 LED 8
Boiler powered on GREEN n/a n/a n/a n/a n/a n/a n/a
Flame presence GREEN n/a n/a n/a n/a n/a n/a YELLOW
CH water temp. ≤ 25°C GREEN OFF OFF OFF OFF OFF OFF n/a
26°C < CH water temp. ≤ 35°C GREEN RED OFF OFF OFF OFF OFF n/a
36°C < CH water temp. ≤ 45°C GREEN OFF RED OFF OFF OFF OFF n/a
46°C < CH water temp. ≤ 55°C GREEN OFF OFF RED OFF OFF OFF n/a
56°C < CH water temp. ≤ 65°C GREEN OFF OFF OFF RED OFF OFF n/a
66°C < CH water temp. ≤ 75°C GREEN OFF OFF OFF OFF RED OFF n/a
76°C < CH water temp. ≤ 85°C GREEN OFF OFF OFF OFF OFF RED n/a
No. 1 chart – Correlation between LED SIGNALLING – BOILER STATUS when boiler is operating
Malfunction LED 1 LED 2 LED 3 LED 4 LED 5 LED 6 LED 7 LED 8
No electric power OFF OFF OFF OFF OFF OFF OFF OFF
Safety thermostat shutdown GREEN OFF RED L OFF OFF OFF OFF OFF
Flue gas thermostat shutdown GREEN OFF OFF RED L OFF OFF OFF OFF
Flame absence shutdown GREEN OFF OFF OFF RED L OFF OFF OFF
Fluid circulation shutdown GREEN OFF OFF OFF OFF RED L OFF OFF
Fan shutdown GREEN OFF RED L OFF OFF OFF OFF YELLOW L
Flow alarm (>85°C) GREEN OFF OFF OFF OFF OFF RED L n/a
DHW probe alarm GREEN RED L OFF OFF OFF OFF OFF OFF
Flow probe alarm GREEN RED L OFF OFF OFF OFF OFF YELLOW L
Water tank probe alarm GREEN RED LA OFF OFF OFF OFF OFF YELLOW LA
Faulty remote control connection GREEN OFF OFF RED L OFF OFF OFF YELLOW L
No. 2 chart – Correlation between LED SIGNALLING – BOILER STATUS when boiler is malfunctioning
Key chart to acronyms
OFF LED off
RED LED on and fixed (colored as indicated in the chart)
RED L LED or LEDs blinking simultaneously (colored as indicated in the chart)
RED LA LEDs blinking alternatively (colored as indicated in the chart)
n/a LED status is not relevant

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1.2. Operating the boiler
1.2.1. Switching on
The following procedure is to be implemented only after the boiler is installed and tested by a qualified fitter.
• Open the gas stop cock;
• turn ON the power switch external to the boiler (no. 1 LED turns on);
• select boiler operation mode via no. 9 selector (pic. 1);
• set desired CH temperature via no. 11 knob (pic. 1);
• In KC model, set desired domestic hot water temperature via no. 10 knob (pic. 1); In KR model equipped with external cylinder, set
desired domestic hot water temperature directly on the external cylinder (see its instruction manual);
• Set desired room temperature by means of the room thermostat in the premises (when available).
When the flame on the burner turns on, no. 8 yellow LED turns on.
WARNING
Should the boiler be left inactive for a long time, particularly when boiler is LPG fired, ignition might be difficult.
Before starting the boiler switch on another gas powered device (e.g. kitchen range).
Beware that even by following this procedure, the boiler might still experience some starting difficulties and shut down once or
twice. Resume boiler operation by turning no. 9 knob to the reset position for two seconds and back to the desired position.
1.2.2. Operation
CENTRAL HEATING
Set desired CH water temperature via no. 11 knob (pic. 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 an authorized Service Centre (see 3.2.11. paragraph).
Instantaneous central heating water temperature is displayed on the control board via no. 2 through no. 7 LED’s (pic. 1).
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 (see 3.2.11. paragraph), waiting time procedure is aborted and boiler
re-ignited.
DOMESTIC HOT WATER
Domestic hot water supply is activated in KC model and KR model equipped with an external cylinder (optional equipment). Such func-
tion always has priority over CH water supply.
In KC model, set desired domestic hot water temperature via no. 10 knob (pic.1). It can be adjusted within a 35°C to 57°C range (from
full counter-clockwise position to full clockwise position);
In KR model equipped with external cylinder (optional equipment), set desired domestic hot water temperature directly on the external
cylinder (see its instruction manual); no. 10 knob is not functional in this model operation.
WARNING
In KC model, a special adjusting device is installed, which limits domestic hot water flow rate to 13 liter per minute (KC 24), and
to 16 liter per minute (KC 32). Domestic hot water temperature supplied depends on no. 10 adjusting device, on the quantity
requested by the user and on water mains supply temperature.
In KC model, DHW liter per minute flow depends on the boiler’s thermal capacity and water mains supply temperature, according to the
following formula:
K
l = DHW liter per min. = --------
∆T
K represents:
- 401 in KC 24 model
- 507 in KC 32 model
∆t = DHW temperature – water mains supply temperature
E.g. in KC 24 model, when water mains supply temperature is 8°C and DHW is required to be 38°C, in order to have a shower, the value
of ∆t is:
∆t = 38 °C – 8 °C = 30 °C
and DHW liters (l per minute) available at the required temperature of 38°C are:
I = 401/30 = 13,4 [liter per minute] (mixed water at the tap)
In contrast, in KR model equipped with an external cylinder (optional equipment), available DHW flow depends on the cylinder capacity.
In KR model with external cylinder (optional equipment), every 15 days, the anti-Legionella function is activated; it consists in heating up
the cylinder to 65°C for 30 minutes, regardless of boiler mode setting.

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ANTI-FROST
The boiler is equipped with anti-frost function, which is active in SUMMER/WINTER/ANTI-FROST modes.
When central heating water temperature sensor detects a water temperature of 5°C, the boiler is switched on and stays on at minimum
heat output until central heating water temperature reaches 30°C or 15 minutes have elapsed.
Should boiler shut down, pump operation is still granted.
In KC model, anti-frost function protects the domestic hot water system as well.
When domestic hot water probe detects a temperature of 5°C, the boiler ignites and stays on at minimum heat output until domestic hot
water temperature reaches 10°C or 15 minutes have elapsed (the deviating valve is set to domestic hot water position).
Should boiler shut down, pump operation is still granted.
In CH only boilers equipped with a DHW supply external cylinder, anti-frost function protects the cylinder as well. The function is active
only for cylinders equipped with β=3435 type NTC probe (refer to cylinder technical data).
When cylinder water temperature probe detects a water temperature of 5°C, the boiler is switched on and stays on at minimum heat ou-
tput until cylinder water temperature reaches 10°C or 15 minutes have elapsed (the deviating valve is set to domestic hot water position).
Should the boiler shut down, pump operation is granted.
Anti-frost function protects the boiler only and not the whole central heating system.
Central heating system is to be protected by means of an ambient thermostat, although this is disabled when the
boiler is set to the anti-frost and OFF modes. Should anti-frost protection be necessary for the boiler and CH system,
select winter position through no. 9 knob.
CH system can be effectively protected from freezing by means of specific anti-freezing addictives suitable in multi-metal systems.
Do not use automotive anti-frost products, and periodically check anti-frost product effectiveness.
PUMP AND DEVIATING VALVE ANTI-BLOCKING FUNCTION
Where the boiler is to remain inactive and:
- no. 9 selector is not set to the OFF position;
- boiler is not disconnected from electric main power supply;
the circulation pump (KC and KR) and three-way valve (KC), are operated for 3 minutes every 24 hours in order to prevent blockage.
1.2.3. External probe operation (optional equipment)
The boiler can be equipped with an external temperature probe (optional equipment), through which the boiler adjusts CH water tem-
perature according to outdoor temperature, in other words, increasing CH water temperature when outdoor temperature decreases and
vice-versa, providing increased energy saving operation (such boiler mode is called “sliding temperature operation”) .
Boiler microprocessor program determines CH water temperature variations.
When an external temperature probe is connected to the boiler, CH water temperature adjusting knob, no.
11 (pic. 1), loses its function and becomes a fictitious room temperature adjusting device.
When no. 11 knob is turned fully counter-clockwise, selected room temperature is 15°C; when set to 9:00
hours selected room temperature is 18°C; when set to 12:00 hours selected room temperature is 25°C;
when set to 3:00 hours selected room temperature is 32°C; when is turned fully clockwise selected room
temperature is 35°C;
For best curve setting, it is advisable a position close to 20°C.
Refer to 3.2.14. paragraph for detailed sliding temperature operation.

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1.3. Boiler shut-down
Should any malfunction occur, boiler automatically shuts down.
Refer to no. 1 and no. 2 charts (on page 7) for boiler status detection.
In order to detect the probable malfunction causes, see, in addition to no. 2 chart, no. 7 “Troubleshooting” paragraph at the end of the
manual, as well.
Follow the described procedure with respect to the type of shut-down.
1.3.1. Burner shut-down
When the burner shuts down due to flame extinguishing, no. 5 LED (red) starts flashing. Should this happen proceed as follows:
- check the gas stopcock to be open, and gas network is actually providing service, by lighting a gas powered kitchen appliance such as
a kitchen range or oven.
- once gas presence is verified, reset the burner by turning no. 9 knob (pic. 1) to the reset position for 2 seconds, and then to the
desired mode position: should the boiler not start shut down, and after performing three reset procedures, contact an authorized Service
Centre or qualified personnel for service.
Should frequent burner shut down occur, a recurrent malfunction might be present: contact an authorized Service Centre or qualified
personnel for service.
1.3.2. Shut-down due to overheating
When CH flow water overheats the boiler is shut down, no. 3 LED (red) starts flashing.
Should the above happen contact an authorized Service centre or qualified personnel for service.
1.3.3. Shut-down due to incorrect fluid circulation
Should CH water circulation not be adequate, the primary flow switch intervenes, the boiler is shut-down, and no. 6 LED (red) starts
flashing.
The following 2 instances may have occurred:
a) no. 12 water pressure gauge (pic. 1) indicates a pressure value lower than 1 bar; in this instance follow the loading procedure as below
described:
- turn the loading tap (pic. 2) counter-clockwise in order to allow water inlet;
- keep the loading tap open until the water pressure gauge reads 1-1.3 bar;
- close the loading tap by turning it clockwise;
- reset the burner by turning no. 9 knob to the reset position for 2 seconds, and then to the desired mode position.
Should the boiler shut down again, contact an authorized Service Centre or qualified personnel for service.
Once the loading procedure is completed, properly close the loading tap. Should the tap not be appropriately closed, as
pressure increases, CH system safety valve may open and water flow out.
b) no. 12 water pressure gauge (pic. 1) indicates a correct pressure value (1-1.3 bar); in this instance contact an authorized Service Cen-
tre or qualified personnel for service.
LOADING TAP
pic. 2 - Loading tap

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1.3.4. Shut-down due to inadequate air/flue gas draught
Should the boiler shut down due to air intake and/or flue gas discharge ducts malfunction, no. 4 LED (pic. 1) starts flashing. Should that
happen, contact an authorized Service Centre or qualified personnel for service.
1.3.5. Shut-down due to fan malfunction
Fan operation is constantly monitored and in case of malfunction the burner is turned off and no. 3 and no. 8 LEDs (pic. 1) start flashing
simultaneously.
The above status continues until correct fan operation is restored.
Should the boiler not re-start and still remain in the above status, contact an authorized Service Centre or qualified personnel for service.
1.3.6. Flow alarm
Should flow temperature rise above 85°C, no. 7 LED (pic. 1) start flashing and the burner is turned off.
Normal boiler operation will be restored once flow temperature decreases below 85°C.
1.3.7. Alarm due to failure of temperature probes
Should the temperature probes malfunction, the following LEDs turn on:
- no. 2 and no. 8 LEDs start flashing simultaneously when flow probe malfunction occur;
- no. 2 LED start flashing when DHW probe malfunction occur (KC);
- no. 2 and no. 8 LEDs start alternatively flashing when external cylinder probe malfunction occur (KR equipped with external cylinder).
Contact an authorized Service Centre or qualified personnel for service.
1.3.8. Alarm due to remote control malfunction
Should the boiler receive incorrect information from the OpenTherm remote control (optional equipment), or should it not receive any
(due to remote control malfunctioning, or incorrect connection between the boiler and the remote control), no. 2 and no. 8 LEDs start
flashing simultaneously.
Contact an authorized Service Centre or qualified personnel for service.
1.4. Maintenance
Have the boiler routinely serviced, following the schedule described in the relevant section of this manual.
Appropriate boiler maintenance ensures efficient operation, environment preservation, and safety for people, animals and
objects.
Qualified personnel only are to service the boiler.
Manufacturer recommends Customers to contact authorized Service Centre for maintenance and repairs; they are best qualified
to implement such procedures.
1.5. Notes for the user
The user may only access boiler parts that can be reached without using technical equipment and/or tools: the user is not authorized to
remove boiler casing and operate on any internal part.
No one, including qualified personnel, is authorized to modify the boiler.
The manufacturer shall not be held responsible for damage to people, animals, or property due to tampering or improper intervention to
the boiler.
Should the boiler be left inactive for a long time and power main supply disconnected, the pump might need to be un-blocked.
Such servicing includes boiler casing removal and access to boiler internal parts, therefore only qualified personnel may perform it.
Pump blockage may be avoided by adding filming additives suitable for multi-metal systems to water.

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2. Technical characteristics and dimensions
2.1. Technical characteristics
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;
Both models are available in the following heat outputs:
KC 24 and KR 24 = 23.7 kW.
KC 32 and KR 32 = 31.4 kW.
Both models are equipped with electronic ignition and ionization flame 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 different country from specified 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 flame detection
- Stainless steel, fully pre-mixed burner
- Mono-thermal, high efficiency, composite and stainless steel heat exchanger with air purging device
- Twin shutter, modulating gas valve with constant air/gas ratio
- Modulating, electronically managed flue gas discharge fan
- Three-speed pump with air purging device
- Safety flow-switch, preventing operation with low water pressure in the CH system
- CH temperature probe (KC and KR) 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)
- DHW priority flow switch (KC)
- DHW flow limiting device; 13 liter/min (KC 24), 16 liter/min (KC 32)
User interface
- Boiler mode selector: OFF, RESET, WINTER, SUMMER, ANTI-FROST
- CH temperature adjusting switch: 20/78°C (standard range), or 20/45°C (reduced range)
- DHW temperature adjusting switch (KC): 35/57°C.
- Led displayed CH water temperature
- CH water pressure gauge
- Light emitting diodes indicating:
• power main supply connection;
• flame detection;
• burner shut-down due to flame extinguishing;
• burner shut-down due to overheating;
• burner shut-down due to flue gas pressure switch intervention;
• burner shut-down due to inadequate CH water circulation;
• burner shut-down due to fan malfunction;
• malfunction of temperature probes;
• remote control faulty connection.

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Operating characteristics
- CH mode electronic flame modulation, timer controlled flame rising ramp (50 seconds)
- DHW mode electronic flame modulation (KC and KR with external cylinder)
- DHW priority function (KC and KR with external cylinder)
- Flow anti-frost function: ON at 5°C; OFF at 30°C or after 15 minutes operation when CH water > 5°C
- DHW anti-frost function (KC): ON at 5°C; OFF at 10°C or after 15 minutes operation when DHW temperature > 5°C
- External cylinder anti-frost function (KR + external cylinder equipped with NTC probe): ON at 5°C; OFF at 10°C or after 15 minutes
operation when external cylinder water temperature > 5°C
- Timer controlled “chimney sweep” function: 15 minutes
- Anti-Legionella function (KR equipped with optional external cylinder)
- Maximum CH input adjusting trimmer
- Ignition heat input adjusting trimmer
- CH water temperature range adjusting device: standard or reduced
- Ignition flame spread function
- Timer controlled CH thermostat: 240 seconds standard range, 120 seconds reduced range
- Post-circulation function in CH mode, anti-frost and chimney sweep mode: 180 seconds
- Post-circulation function in DHW supply mode (KC and KR with external cylinder): 30 seconds
- Post-circulation function for CH temperature > 85°C: 30 seconds
- Post ventilation function following operation: 10 seconds
- Post ventilation function for CH temperature > 95°C
- Pump (KC and KR) and deviating valve (KC) anti-blocking function: 180 seconds operation after 24 hours of non operation
- Ready for connection to a room thermostat
- Ready for connection to an external probe (manufacturer delivered optional equipment)
- Ready for connection to an OpenTherm remote control (manufacturer delivered equipment)
- Ready for serving different zones

14
2.2. Dimensions
Bottom view Top view
pic. 3 - Dimensions
S Condensate drain
F Water mains intake
G Gas intake
SI Inspection trap plug
M CH system flow
C DHW flow (KC model only)
SV 3-bar safety valve drain cock
RC Filling tap
R CH system return
RS Drain cock

15
2.3. Hydraulic layouts
1. Condensate drain siphon
2. Modulating gas valve
3. Safety thermostat
4. CH temperature probe
5. Modulating fan
6. Primary fluid flow 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. Flow limiting device
23. Loading tap
24. Domestic cold water flow meter with filter
25. Secondary plate exchanger
26. DHW probe
27. Automatic by-pass
28. Motorized 3-way valve
S Condensate drain
G Gas intake
M CH system flow
C DHW flow
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 fluid flow 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. Loading tap
23. Automatic by-pass
S Condensate drain
G Gas intake
M CH system flow
F Water mains intake
R CH system return
pic. 4 - KC model hydraulic layout
pic. 5 - KR model hydraulic layout
28 27 26 25 24
23
11
10
9
8
7
6
5
4
3
2
3
122
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
3
122
21
20
19
18
17
16
15
14
13
12
23

16
2.4. Operating data
Burner pressures must be verified 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)
Flue gas
CO2
[%]
min max min max min max
Methane Gas G20 23.7 6.5 22.7 7.3 24.8 7.3 28.0 20 8.8 ÷ 9.1
Propane Gas G31 23.7 6.5 22.7 7.3 24.8 7.3 28.0 37 9.8 ÷ 10.1
No. 3 chart – KC 24 model adjustment rates
Hot water supply ∆T 45°C = 8.9 l/min
Hot water supply ∆T 40°C = 10 l/min
Hot water supply ∆T 35°C = 11.5 l/min
Hot water supply ∆T 30°C = 13.4 l/min *
Hot water supply ∆T 25°C = 16.1 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)
Flue gas
CO2
[%]
min max min max min max
Methane Gas G20 31.4 8.7 30.5 9.6 33.2 9.6 35.4 20 8.8 ÷ 9.1
Propane Gas G31 31.4 8.7 30.5 9.6 33.2 9.6 35.4 37 9.8 ÷ 10.1
No. 4 chart – KC 32 model adjustment rates
Hot water supply ∆T 45°C = 11.3 l/min
Hot water supply ∆T 40°C = 12.7 l/min
Hot water supply ∆T 35°C = 14.5 l/min
Hot water supply ∆T 30°C = 16.9 l/min *
Hot water supply ∆T 25°C = 20.3 l/min *
*Note: mixed water to the tap
KR 24
Function
Max. CH
input
(kW)
CH
output
(80-60°C)
[kW]
CH
output
(50-30°C)
[kW]
Gas mains
pressure
(mbar)
Flue gas
CO2
[%]
min max min max
Methane Gas G20 23.7 6.5 22.7 7.3 24.8 20 8.8 ÷ 9.1
Propane Gas G31 23.7 6.5 22.7 7.3 24.8 37 9.8 ÷ 10.1
No. 5 chart – KR 24 model adjustment rates
KR 32
Function
Max. CH
input
(kW)
CH
output
(80-60°C)
[kW]
CH
output
(50-30°C)
[kW]
Gas mains
pressure
(mbar)
Flue gas
CO2
[%]
min max min max
Methane Gas G20 31.4 8.7 30.5 9.6 33.2 20 8.8 ÷ 9.1
Propane Gas G31 31.4 8.7 30.5 9.6 33.2 37 9.8 ÷ 10.1
No. 6 chart – KR 32 model adjustment rates

17
2.5. General characteristics
KC MODEL KC 24 KC 32
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 (∆t 30 °C) l/min 13.4 16.9
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
Net weight kg 38.5 40.0
Methane gas consumption at maximum CH input (*) m3/h 2.51 3.32
Propane gas consumption at maximum CH input kg/h 1.84 2.44
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
No. 7 chart – KC model general specifications
(*) Value referred to 15°C - 1013 mbar
(**) Maximum water temperature 83°C, expansion vessel pressure 1 bar
KC 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 off % 0.2 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) % 96.0 - -
Maximum heat output efficiency rating (30/50°C) % 104.8 - -
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
No. 8 chart – KC 24 model combustion rates
KC 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 off % 0.2 0.2 -
Chimney heat loss with burner on % 2.4 2.1 -
Flue gas system mass flow rate g/s 15.7 4.1 -
Flue gas temp. – air temp °C 54 51 -
Maximum heat output efficiency rating (60/80°C) % 96.6 - -
Maximum heat output efficiency rating (30/50°C) % 105.4 - -
Minimum heat output efficiency rating (30/50°C) % - 106.3 -
30% heat output efficiency rating % - - 108.7
Efficiency rating (according to 92/42/CEE) -
NOx emission class - 5
No. 9 chart – KC 32 model combustion rates

18
KR MODEL KR 24 KR 32
Equipment category - II2H3P II2H3P
Minimum CH system pressure bar 0.5 0.5
Maximum CH system pressure bar 3 3
Electric power supply – voltage / frequency V - Hz 230 - 50 230 - 50
Fuse A 2 2
Maximum power consumption W 145 145
Electric protection rating IP X4D X4D
Net weight kg 37.5 39.0
Methane gas consumption at maximum CH input (*) m3/h 2.51 3.32
Propane gas consumption at maximum CH input kg/h 1.84 2.44
Maximum CH working temperature °C 83 83
Total capacity of expansion vessel l 10 10
Maximum recommended CH system capacity (**) l 200 200
No. 10 chart – KR model general specifications
(*) Value referred to 15°C - 1013 mbar
(**) Maximum water temperature 83°C, expansion vessel pressure 1 bar
KR 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 off % 0.2 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) % 96.0 - -
Maximum heat output efficiency rating (30/50°C) % 104.8 - -
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
No. 11 chart – KR 24 model combustion rates
KR 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 off % 0.2 0.2 -
Chimney heat loss with burner on % 2.4 2.1 -
Flue gas system mass flow rate g/s 15.7 4.1 -
Flue gas temp. – air temp °C 54 51 -
Maximum heat output efficiency rating (60/80°C) % 96.6 - -
Maximum heat output efficiency rating (30/50°C) % 105.4 - -
Minimum heat output efficiency rating (30/50°C) % - 106.3 -
30% heat output efficiency rating % - - 108.7
Efficiency rating (according to 92/42/CEE) -
NOx emission class - 5
No. 12 chart – KR 32 model combustion rates

19
3. Instructions for the fitter
3.1. Installation standards
This is an II2H3P category boiler and must be installed in compliance with laws and standards enforced in the country of installation,
which are herein considered as entirely transcribed.
3.2. Installation
Accessories and spare parts for installation and service procedures are to be supplied by the Manufacturer. Should non
original accessories and spare parts be employed, boiler proper performance is not guaranteed.
3.2.1. Packaging
Boiler is shipped in a sturdy cardboard box.
Remove boiler from cardboard box and check its integrity.
The packing materials can be recycled. Disposal of must be managed via appropriate waste collection sites.
Keep packaging out of reach of children, as it may be dangerous.
Manufacturer shall not be held responsible for harm to people and/or animals, and/or damage to property due to failure in following the
above mentioned instructions.
Packaging includes:
- copper pipe kit for boiler connection to the gas mains, to the CH system (KC and KR) and DHW system (KC);
- wall hanging bracket;
- a bag containing:
a) boiler installation, use and maintenance manual.
b) boiler wall mounting template (pic. 6).
c) metal plate for fixing the boiler to the wall.
d) two screws and wall plugs for fixing the metal plate to the wall.
3.2.2. Choosing where to install the boiler
The following must be taken into account when choosing where to install the boiler:
- 3.2.6. “Air intake /flue gas discharge system” paragraph instructions;
- check the wall for sturdiness, avoiding weak areas;
- do not hang the boiler above any equipment which may prejudice proper operation (steam and greasy vapor emitting kitchen applian-
ces, washing machines, etc.).

20
pic. 6 - Installation template
3.2.3. Positioning the boiler
Each boiler is supplied with a paper template (pic. 6), within its packa-
ging, allowing arrangement of CH pipe system, DHW pipe system,
gas supply pipe system and air intake/flue gas discharge system
before actually installing the boiler.
The template is made of heavy-duty paper, it is to be affixed to the
wall where the boiler is to be mounted using a carpenter’s level. It
provides all the indications required to drill the boiler fixing holes to
the wall, procedure which is done using two screws and wall plugs.
The lower area of the template displays where to mark the exact point
at which the couplings are to be positioned for boiler connection to
the gas supply pipe, water mains supply pipe, DHW flow pipe, CH
flow and return pipes.
The upper area of the template displays where air intake and flue gas
ducts are to be positioned.
Since the temperature of the walls on which the boiler
is mounted and external temperature of coaxial
air/flue gas system do not exceed 60°C, no minimum
distance from flammable walls is to be accounted for.
Boilers with split pipe flue system: in presence of
flammable walls and flue gas ducts through such
walls, ensure proper insulation between wall and
flue gas ducts
3.2.4. Installing the boiler
Before connecting the boiler to CH and DHW networks,
clean the pipes carefully.
Prior to operate a NEW system eliminate any metallic
leftover during manufacturing and welding process,
and any oil or grease deposits, which might reach the
boiler and damage it or alter its operation.
Prior to operate a MODERNIZED system (addition of
radiators, boiler replacement, etc.), clean it throughout
so as to remove possible sludge and foreign particles.
In order to clean the system, employ non acid product
available on the market. Do not use solvents as they could
damage system components.
Furthermore, in the central heating system (either new or
modernized), it is always advisable to add to water, with
adequate concentration, suitable products inhibiting
corrosion in multi-metal systems, which produce a
protective film on internal metal surfaces.
Manufacturer shall not be held responsible in case of harm
to people and/or animals, or property damage due to failure
in adhering to the above stated instructions.
For all kinds of heating plants, it is necessary to install the
seal with filter (supplied with the boiler) on the return duct,
as shown in pic. 7.
Should boiler be mounted in an existing system, install a
filter which can be inspected (Y-shaped type) with
Ø 0.4mm-mesh span, on return pipe before the boiler.
In order to install the boiler proceed as follows:
- affix the template (pic. 6) to the wall;
- drill two 12 mm Ø holes in the wall to accommodate the boiler support
bracket wall plugs;
- arrange air intake/flue gas system path in the wall as needed;
- secure boiler support bracket to the wall by means of the wall plugs
supplied with the boiler;
- position gas supply network coupling (G), water mains supply coupling
(F), DHW flow coupling (C, only in KC model), CH flow coupling (M), and
CH return coupling (R), and condensate drain coupling (S), as shown on
the template (refer to its lower area );
- position the boiler to the supporting bracket on the wall;
- connect the boiler to network pipes by means of the coupling kit supplied with the boiler (refer to 3.2.9. paragraph);
- connect the boiler to pipe for condensate discharge (refer to 3.2.9. paragraph);
- connect the boiler to the air intake and flue gas exhaust system (refer to 3.2.6. paragraph);
- connect electric power supply, ambient thermostat (when available) and other available accessories (refer to the following paragraphs).
pic. 7 - Installation of the seal with filter
Seal with filter