Fondital Tahiti Condensing 24 kW Combi (KC) Quick start guide

IST 03 C 000- 01
INSTALLATION,
USE AND MAINTENANCE
TAHITI CONDENSING
GB
Gas fired wall Mounted condensing boiler
Tahiti Condensing 24, 28, 32 kW Combi (KC)
Tahiti Condensing 24, 28, 32 kW Regular (KR)
High quality Italian product
MADE IN ITALY

2
Natural Gas
Fondital Tahiti Condensing 24 kW Combi (KC)
G.C.N° 47 309 01
Fondital Tahiti Condensing 28 kW Combi (KC)
G.C.N° 47 309 02
Fondital Tahiti Condensing 32 kW Combi (KC)
G.C.N° 47 309 03
Fondital Tahiti Condensing 24 kW Regular (KR)
G.C.N° 41 309 01
Fondital Tahiti Condensing 28 kW Regular (KR)
G.C.N° 41 309 02
Fondital Tahiti Condensing 32 kW Regular (KR)
G.C.N° 41 309 03
Benchmark places responsibilities on both manufacturers and installers. The purpose is to ensure that customers are provided with the
correct equipment for their needs, that it is installed, commissioned and serviced in accordance with the manufacturer’s instructions by
competent persons and that it meets the requirements of the appropriate Building Regulations. The Benchmark Checklist can be used to
demonstrate compliance with Building Regulations and should be provided to the customer for future reference.
Installers are required to carry out installation, commissioning and servicing work in accordance with the Benchmark Code of Practice
which is available from the Heating and Hotwater Industry Council who manage and promote the Scheme.
Visit www.centralheating.co.uk for more information.

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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.

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1. General information for fitters, maintenance technicians and users
1.1. General warnings
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 tter is to advise the user about boiler operation and its safety devices. This Manual
must be left along with the Benchmark commissioning booklet with the boiler as Regulation 29 of the HSC Gas safety (installation and
use) Regulations 1998.
This boiler is designed for connection to a domestic heating or hot water system.
Any other use is deemed as improper and as such dangerous. Under no circumstances will the manufacturer be held
responsible for damage or injury to persons or animals caused by errors in the installation and/or use of the appliance,
or through non-compliance with current local and national standards and/or the manufacturer’s instructions.
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.
In GB, the installation must be carried out by a Registered Installer. To check for authorised qualied engineers please contact CORGI
01256 372400. It must be carried out in accordance with the relevant requirements of the:
• Gas Safety Regulations;
• The appropriate Building Regulations either The Building Regulation, The Building Regulations (Scotland), Building Regulations
(Northern Ireland);
• The Water Fittings Regulations or Water Bylaws in Scotland;
• The current I.E.E. Wiring Regulations.
Where no specic instructions are given, reference should be made to the relevant British Standards Code of Practice.
In IE, the installation must be carried out by a competent Person and installed in accordance with the current edition of I.E. 813
“Domestic Gas Installations”, the current Building Regulations and reference should be made to the current ETCI rules for electrical
installations.
The commissioning of the boiler and any subsequent works carried out on the appliance must be effected by an appropriately qualied
technician or an approved Fondital Helpline Service Centre.
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. In case of doubt, do not attempt to use the product but refer to the supplier. Packing materials (cardboard box, wooden
crate, nails, staples, plastic bags, polystyrene, etc.) must not be left within reach of children in that these items represent a potential
hazard and must be disposed of in a responsible manner.
Do not obstruct the air intake or ue exhaust grills and terminals.
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.
In the event of failure and/or malfunction, shut down the system. Do not interfere with or attempt any repairs. Call for professionally
qualied technical assistance only. Fondital helpline UK 08700 34 8820.
Any warranty repairs to the appliance must be carried out exclusively by the manufacturer’s authorised service centre using original
spare parts. 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 ef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.
Before carrying out any cleaning or maintenance operations, disconnect the appliance from the mains electricity supply by switching off
at the main switch and/or any other isolating device.
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-freeze function will not be operative.
Should there be a risk of freezing, add anti-freeze: it is not advisable to empty the system as this may result in damage; use specic
anti-freeze products suitable for multi-metal heating systems.

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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.
TRANSCO GAS EMERGENCY 0800 111 999
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 “operating instructions” of this manual must be read carefully as it provides information on the operating and the operating limits of
the appliance.
This appliance must be used exclusively in an un-vented central heating system.
The warnings contained in this chapter have been written for the appliance user, the installer and the service engineer.
1.2. Product conformity
FONDITAL S.p.a. declare that all its products are manufactured to a high specication and in compliace with the relevant standards.
All FONDITAL boilers are CE certied and possess technical and functional characteristics that comply with the following standards:
UNI EN 297 for GAS-FIRED CENTRAL HEATING BOILERS TYPE B OF NOMINAL HEAT INPUT ≤ 70 kW
EN 483 for GAS-FIRED CENTRAL HEATING BOILERS TYPE C OF NOMINAL HEAT INPUT ≤ 70 kW
UNI EN 677 for GAS-Fired CENTRAL HEATING BOILERS. SPECIFIC REQUIREMENTS FOR CONDENSING BOILERS WITH NOMINAL
HEAT INPUT ≤ 70 kW
Gas red boilers also comply with the following directives:
GAS APPLIANCES DIRECTIVE 90/396 CEE for CE compliance
LOW VOLTAGE DIRECTIVE 2006/95 CE
BOILER EFFICIENCY DIRECTIVE 92/42 CE
ELECTROMAGNETIC COMPATIBILITY DIRECTIVE 89/336 CE
The materials used such a copper, brass, stainless steel, etc. form a compact, homogeneous, highly functional unit that is easy to install
and simple to operate. In its simplicity, the wall-mounted appliance is equipped with all the appropriate accessories required to make it a
fully independent boiler capable of satisfying domestic hot water production and central heating needs. All boilers are fully inspected and
are accompanied by a quality certicate, signed by the inspector, and a guarantee certicate. This manual must be kept in a safe place
and must accompany the boiler at all times.
FONDITAL S.p.a. will not be held responsible for any misinterpretation of this manual resulting from the inaccurate translation of
same.
FONDITAL S.p.a. will not be held responsible for the consequences in the case of non observance of the instructions contained
in this manual or in the case where actions not specifically described herein are undertaken.
FONDITAL S.p.a. declare that no substances harmful to health are contained in the appliance or used during appliance
manufacture and have not used or intend to use any of the following substances in the manufacture of Fondital heating
products:
- Asbestos
- Mercury
- CFC’s
It is a condition of the manufacturers warranty that the Benchmark Commissioning Checklist is fully
completed and left with the appliance.

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CONTEST
1.General information for fitters, maintenance technicians and users pag. 4
1.1. General warnings pag. 4
1.2. Product conformity pag. 5
2.Instructions for the user pag. 7
2.1 Control panel pag. 7
2.2 LCD pag. 8
2.3 BOILER STATUS - LCD ACTIVATION CORRESPONDENCE pag. 9
2.4 Operating the boiler pag. 10
2.4.1. Switching on pag. 10
2.4.2. CH function pag. 10
2.4.3. DHW function pag. 10
2.4.4. ANTI-FREEZE FUNCTION pag. 11
2.4.5. PUMP AND THREE WAY VALVE ANTI-SEIZE FUNCTION pag. 12
2.4.6. External probe operation (optional equipment) pag. 12
2.5.Boiler lockout pag. 13
2.5.1. Burner lockout pag. 13
2.5.2. Shut-down due to overheating pag. 13
2.5.3. Shut-down due to inadequate air/ue gas draught pag. 13
2.5.4. Shut-down due to incorrect uid circulation pag. 13
2.5.5. Shut-down due to fan malfunction pag. 14
2.5.6. Alarm due to failure of temperature probes pag. 14
2.5.7 Flow alarm pag. 14
2.5.8. Alarm due to external probe malfunction pag. 14
2.6. Maintenance pag. 14
2.7. Notes for the user pag. 14
3. Technical characteristics and dimensions pag. 15
3.1. Technical characteristics pag. 15
3.2. Dimensions pag. 16
3.3. Layout pag. 17
3.4. Hydraulic layouts pag. 18
3.5. Operating data pag. 19
3.6. General characteristics pag. 20
4.Instructions for the fitter pag. 24
4.1. Reference standard pag. 24
4.2. System details pag. 25
4.2.1. Central heating circuit pag. 25
4.2.2. Filling the central heating system pag. 25
4.2.3. Domestic hot water circuit pag. 25
4.3. Site requirements pag. 26
4.3.1. Choosing where to install the boiler pag. 26
4.3.2. Positioning the boiler pag. 26
4.3.3. Boiler room ventilation pag. 28
4.3.4. Flue pag. 28
4.4. Installation (authorised personnel) pag. 29
4.4.1. Packaging pag. 29
4.4.2. Installing the boiler pag. 29
4.4.3. Gas main connection pag. 30
4.4.4. Hydraulic connections pag. 30
4.5. Flue options pag. 32
4.5.1. Air intake/ue gas discharge system pag. 32
4.5.2. Air/ue gas system duct conguration pag. 33
4.5.3. Ø 100/60 mm air/flue gas coaxial duct system pag. 35
4.5.4. Ø 80 mm air/ue gas split duct system pag. 36
4.5.5. Electrical supply connection pag. 37
4.5.6. Selecting central heating output range pag. 37
4.5.7. Room thermostat connection (optional equipment) pag. 38
4.5.8. External temperature probe installation (optional equipment) and “sliding temperature” operation pag. 38
4.5.9. Loading the system pag. 40
5.Commissioning pag. 41
5.1. Commissioning the boiler pag. 41
5.2. Setting the timer pag. 41
5.3. Checking pag. 41
5.4. Switching on and switching off pag. 41
6. Maintenance pag. 42
6.1. General warnings pag. 42
6.2. Boiler inspection pag. 42
6.3. Combustion analysis pag. 42
6.4. Testing combustion efciency pag. 43
6.5.1. “Chimney sweep” function pag. 43
6.5.2. Measurements pag. 43
6.6. Wiring diagram pag. 44
7. Spare part list pag. 46
8.Troubleshooting pag. 49

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2. Instructions for the user
Fondital is a licensed member of the Benchmark Scheme which aims to improve the standards of installation and commissioning of
domestic heating and hot water systems in the UK and to encourage regular servicing to optimise safety, efciency and performance.
Benchmark is managed and promoted by the Heating and Hotwater Industry Council.
For more information visit www.centralheating.co.uk
Please ensure that the installer has fully completed the Benchmark Checklist on the inside back pages of the installation instructions
supplied with the product and that you have signed it to say that you have received a full and clear explanation of its operation. The
installer is legally required to complete a commissioning checklist as a means of complying with the appropriate Building Regulations
(England and Wales).
All installations must be notied to Local Area Building Control either directly or through a Competent Persons Scheme. A Building Regu-
lations Compliace Certicate will then be issued to the customer who should, on receipt, write the Notication Number on the Bench-
mark Checklist.
This product should be serviced regularly to optimise its safety, efciency and performance. The service engineer should complete the
relevant Service Record on the Benchmark Checklist after each service.
The Benchmark Checklist may be required in the event of any warranty work and as supporting documentation relating to home im-
provements in the optional documents section of the Home Information Pack.
2.1. Control panel
1. Liquid crystal display (LCD)
The LCD displays the boiler status and operating data (see pic. 2).
2. 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 activated only when the boiler is connected to an external cylinder).
When the selector is positioned to SUMMER , the boiler is ready to operate in domestic hot water supply mode (in KR models, do-
mestic hot water supply mode is activated only when the boiler is connected to an external cylinder).
When the selector is positioned to ANTI-FREEZE , only the anti-freeze function is active.
When the selector is positioned to RESET , the boiler is re-activated after a shutdown.
3. DHW 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), to 14
liters 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 temperature adjusting knob
The knob is adjusts central heating water temperature between a minimum of 20 °C and a maximum of 78 °C.
5. Time clock
The time clock is for central heating control only. The clock is provided with a selector switch with three positions:
a) Position “I” CONSTANT: in this position, the clock circuit is always closed (switch on), therefore the boiler will constantly on and will
only shut off upon the request of the room thermostat (if installed) or the heating thermostat;
b) Position “O” HEATING OFF: in this position, the clock circuit is always open (switch off) and the boiler will therefore never igniter for
heating, Domestic hot water will operate on demand;
c) “Central” position PROGRAMMING ACTIVE: in this position, the programming set by the user is active.
pic. 1
51 2 43

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2.2 LCD
a. DHW indicator (tap symbol)
This comes on when the boiler is in domestic hot water mode (DHW mode).
It ashes when the DHW temperature is being regulated via regulator 3(pic. 1).
b. Water heater on indicator
This indicator comes on when external boiler (optional) is activated via regulator 3(pic. 1). Refer to subsection 2.4.3.
Only for model KR.
c. Alphanumeric indicator
This shows the following:
- boiler status
- CH temperature
- CH temperature setting
- DHW temperature setting
- 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 (pic. 1).
e. Boiler lockout indicator
This comes on when there is a malfunction that cannot be reset via the boiler selector (2, pic. 1).
The problem must be solved before the boiler can be restarted (see 2.5).
f. Burner lockout indicator
This comes on when the burner shutdown device activates due to a malfunction.
To restart the boiler, turn the boiler selector (2, pic. 1) to the RESET position for a few seconds and then back to the desired position
(see 2.5).
g. Flame indicator
This comes on when the burner ame is present.
h. Chimney-sweep function indicator (for fitter only)
This comes on when the chimney-sweep function is activated (see 6.4.1).
The water ow temperature and the number of fan revolutions are displayed (in this case the symbol m comes on simultaneously).
i. Thermoregulation indicator (for fitter only)
This comes on when the thermoregulation curve is set.
l. Virtual ambient temperature indicator
When an external probe is installed, this indicator ashes when the virtual ambient temperature is set on regulator 4 pic.1.
m. Fan rev counter (for fitter only)
When the chimney-sweeper function is activated, the symbol h ashes and the water ow temperature and the number of fan revolutions
are displayed alternately (in this case the symbol comes on simultaneously).
pic. 2
a b c d
e
f g h i l
m
Using the three position switch the timer will allow either constant operation, timed operation or central heating off. Move the switch bot-
tom by sliding to the desired position.
The time clock is provided with 72 switches, each of which cover a time interval of 20 minutes (three per hour).
When a rider is switched from the outside (on setting) to the inside of the clock border (off setting),
the circuit is open (switch off) for a period of 20 minutes and then the boiler stops.
For set the time of day, turn the timer outer bezel clockwise, to align the pointer with the correct
time to the nearest 20 minutes. Do not at any time attempt to turn the bezel anti-clockwise.
For set the timed heating program, decide which times of the day the central heating is required.
The heating will operate when the green tappets are set to the outer edge of the bezel.
To ensure the heating stays OFF set the required tappets inwards towards the centre of the bezel.
ON OFF
Tapped position

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2.3 BOILER STATUS – LCD ACTIVATION CORRESPONDENCE
Normal boiler operation
Boiler selector on OFF
Boiler selector on ANTI-FREEZE
Boiler selector on SUMMER or WINTER
No function active
The boiler water temperature is displayed
Boiler selector on SUMMER or WINTER
DHW enabled (mod. KC only)
The boiler water temperature is displayed
Boiler selector on WINTER
CH function active
The boiler water temperature is displayed
Boiler selector on SUMMER or WINTER
Boiler enabled, no function active
The boiler water temperature is displayed
(only for model KR with an optional external boiler)
Table 1 - BOILER STATUS – LCD in normal operation
Malfunction
No electric power
Flame absence shutdown
Safety thermostat shutdown
Flue gas thermostat shutdown
Flow primary temperature sensor alarm
DHW temperature sensor alarm
Only for KC model
Water tank temperature sensor alarm
Only for model KR with an optional external boiler and NTC probe
Fluid circulation shutdown
(pump ON – primary flow regulator OPEN)
Fluid circulation shutdown
(pump OFF – primary flow regulator CLOSE)
Fan shutdown
External temperature sensor alarm
Table 2 - BOILER STATUS - LCD in case of malfunction

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2.4 Operating the boiler
2.4.1 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: LCD shows the current active function (see tables 1 and 2);
- select boiler operation mode via no. 2selector (pic. 1);
- set desired CH temperature (see 2.4.2. paragraph);
- set desired DHW (see 2.4.3. paragraph);
- 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 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. 2 knob to the reset position for two seconds and back to the desired position.
Allow three minutes between each attempt to re-light the boiler.
2.4.2 CH function
Set desired CH water temperature via no. 4 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 tter or an authorized Service Centre (see 4.5.6. paragraph).
During temperature setting, the CH symbol on the LCD ashes and the CH setting is displayed.
When the CH system demands heat, the LCD shows the (xed) CH symbol and the instant temperature of
the CH ow 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 an anti-cycling time between subse-
quent 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 4.5.6. paragraph), anti-cycling procedure is aborted and boiler
re-ignited.
2.4.3 DHW function
Turn the regulator 3(pic. 1) to set the domestic hot water temperature.
DHW operating mode is enabled on model KC and model KR with an external storage heater (optional).
The DHW function always has priority over the heating function.
In model KC, the temperature range is 35°C to 57°C (from the fully anticlockwise to the fully clockwise
position of regulator 3).
During temperature setting, the DHW symbol on the LCD ashes and the DHW temperature is displayed.
In model KR with an (optional) external storage heater, the storage heater can be activated or deactivated
to produce hot water via regulator knob 3.
When you turn regulator 3 to the fully anticlockwise position, the storage-heater-on symbol appears. Turn
regulator 3 until a setting of at least 40 °C is reached.
To deactivate the storage heater, turn regulator 3 fully anticlockwise until the DHW symbol disappears, then back to a setting of at least
40°C.
In model KR with an (optional) external storage heater and NTC probe (10 kΩ @ ß=3435; refer to the
storage heater specications), the temperature range is 35°C to 57°C (from fully anticlockwise to fully
clockwise of regulator 3). During temperature setting, the DHW symbol on the LCD ashes and the DHW
temperature is displayed.
In model KR, with an (optional) external storage heater with a thermostat probe, the desired water temperature must be set on the
storage heater (see instructions attached to the storage heater). Regulator 3has no effect on operation in this conguration, except for
enabling/disabling the storage heater, as explained above.
When there is a demand for hot water, the tap symbol (xed) and the instantaneous ow water tempera-
ture are displayed. The burner-on symbol shows while the burner is in operation.

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WARNING
In KC model, a special adjusting device is installed, which limits domestic hot water flow rate to 13 liter per minute (KC 24), to 14
liters per minute (KC 28) and to 16 liter per minute (KC 32).
Domestic hot water temperature supplied, depends on no. 3 DHW thermostat, on the quantity requested by the user and on
water mains supply temperature.
In KC model, DHW liter per minute ow depends on the boiler’s thermal capacity and water mains supply temperature, according to the
following formula:
K
l = DHW liter per minute = --------
ΔT
Krepresents:
- 401 in KC 24 model
- 444 in KC 28 model
- 507 in KC 32 model
ΔT = DHW temperature – water mains supply temperature
E.g. in KC 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
ΔT is:
ΔT = 38 °C – 8 °C = 30 °C
and DHW liters (l per minute) available at the required temperature of 8 °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 ow 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.
2.4.4 ANTI-FREEZE FUNCTION
The boiler is equipped with anti-freeze function, which is active in SUMMER, WINTER and ANTI-FREEZE modes.
Anti-freeze 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-FREEZE and OFF modes.
Should anti-freeze protection be necessary for the boiler and CH system, select WINTER position through no. 2
knob.
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-freeze 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-freeze function protects the cylinder as well.
The function is active only for cylinders equipped with 10 kΩ @ ß=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
output 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.
In model KR, with an (optional) external storage heater for the production of domestic hot water, which incorporates a temperate sensor
similar to a thermostat, the anti-freeze function DOES NOT protect the storage heater.
In this case the storage heater is protected by setting the boiler to SUMMER or WINTER (via selector 2), by enabling the storage
heater (via regulator 3) as detailed in the previous subsection, and by selecting a temperature on the thermostat above 0°C.
CH system can be effectively protected from freezing by means of specic anti-freezing addictives suitable in multi-metal systems.
Do not use automotive anti-freeze products, and periodically check anti-freeze product effectiveness.

12
pic. 3
15 35
32
25
18
2.4.5 PUMP AND THREE-WAY VALVE ANTI-SEIZE FUNCTION
Where the boiler is to remain inactive and:
- no. 2selector is not set to the OFF position;
- boiler is not disconnected from electric main power supply;
the circulation pump (KC and KR model) and three-way valve (KC model), are operated for 30 second every 24 hours in order to prevent
the components from seizing.
2.4.6 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 sav-
ing 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. 4 (pic. 1), loses its function and becomes
a virtual room temperature adjusting device.
During temperature setting, the virtual ambient temperature symbol
ashes and the temperature setting is displayed.
When no. 4 knob is turned fully counter-clockwise, selected room temperature is 15 °C; when
set to 9:00 o’clock selected room temperature is 18 °C; when set to 12:00 o’clock selected room
temperature is 25 °C; when set to 3:00 o’clock 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 4.5.8 paragraph for detailed sliding temperature operation.
Only original external probes supplied by the manufacturer must be used.
If non-original external probes are used, correct operation of the boiler cannot be guaranteed.

13
fig. 4
Water pressure gauge
2.5 Boiler lockout
Should any malfunction occur, boiler automatically shuts down. Refer to no. 1 and no. 2 charts for boiler status detection.
In order to detect the probable malfunction causes, see, in addition to no. 2 chart, no. 8 “Troubleshooting” paragraph at the end of the
manual, as well.
Follow the described procedure with respect to the type of lockout.
2.5.1 Burner lockout
If the burner shuts down as there is no ame, the burner shutdown symbol is displayed and code E01
ashes.
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 veried, reset the burner by turning no. 2knob (pic. 1) to the reset position for two seconds, and then to the
desired mode position: should the boiler not start shut down, and after performing three reset procedures, contact the Fondital helpline
UK.
Should frequent burner lockout occur, a recurrent malfunction might be present: contact the Fondital helpline UK or qualied personnel
for service.
2.5.2 Shut-down due to overheating
When CH ow water overheats the boiler is shut down, the burner shutdown symbol is displayed and
code E02 ashes.
Should the above happen contact the Fondital helpline UK or CORGI registered engineer with appropriate
competence for service.
2.5.3 Shut-down due to inadequate air/flue gas draught
Should the boiler shut down due to air intake and/or ue gas discharge ducts malfunction, the burner
shutdown symbol is displayed and code E03 ashes (intervention of ue gas thermostats).
Should the above happen contact the Fondital helpline UK or CORGI registered engineer with appropriate
competence for service.
2.5.4 Shut-down due to incorrect fluid circulation
Should CH water circulation not be adequate, the boiler is shut-down.
The boiler shutdown symbol is displayed and codes E10 or E26 ash, depending on the boiler function.
In the rst case (ashing E10 code), the following 2 situations may occur:
a) the water pressure gauge (pic.4) indicates a pressure value lower than 1 bar
Follow the loading procedure as below described:
- open the loading tap upstream the boiler to ll the system with water;
- keep the loading tap open until the water pressure gauge reads 1÷1.3 bar;
- close the loading tap;
- reset the burner by turning no. 2knob to the reset position for 2 seconds, and then to the desired mode position.
Should the boiler shut down again, contact the Fondital helpline UK or CORGI registered engineer with appropriate competence 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) the water pressure gauge (pic.4) indicates a correct pressure value 1÷1.3 bar
Contact an authorized Service Centre or qualied personnel for service.
In the second case (ashing E26 code) contact an Authorised Service Centre or a qualied service engineer.

14
2.5.5 Shut-down due to fan malfunction
Fan operation is constantly monitored and in case of malfunction the burner is turned off and the LCD
shows the boiler shutdown symbol with ashing E17 code.
The above status continues until correct fan operation is restored. Should the boiler not re-start and still
remain in the above status, contact the Fondital helpline UK or CORGI registered engineer with appropri-
ate competence for service.
2.5.6 Alarm due to failure of temperature probes
Should the temperature probes malfunction, the boiler shutdown symbol is displayed and the following codes may ash:
- E05, CH probe: the boiler does not.
- E06, DHW probe (only KC model): the boiler only operates in CH mode, not DHW mode.
- E12, storage probe (only KR model with optional external boiler and NTC temperature probe: 10 kΩ @ ß=3435): the boiler operates in
CH, while DHW production is disabled.
Contact the Fondital helpline UK 08700 34 88 20 or CORGI registered engineer with appropriate competence for service.
2.5.7 Flow alarm
Should ow temperature rise above 85 °C, the burner is turned off.
Normal boiler operation will be restored once ow temperature decreases below 85 °C.
2.5.8 Alarm due to 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(pic. 1), which in this case loses its
function as a virtual ambient temperature regulator (see 2.4.6.).
Contact the Fondital helpline UK 08700 34 88 20 or CORGI registered engineer with appropriate competence for service.
2.6 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.
CORGI registered engineer with the appropriate competence only are to service the boiler.
Manufacturer recommends Customers to contact the Fondital helpline UK for maintenance and repairs; they are best qualified
to implement such procedures.
2.7 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 per-
form it. Pump blockage may be avoided by adding inhibitor suitable for multi-metal systems to water.

15
3 Technical characteristics and dimensions
3.1 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 inputs:
- KC 24 and KR 24 = 23.7 kW
- KC 28 and KR 28 = 26.2 kW
- KC 32 and KR 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 different country from specied may endanger people, animals and objects.
The main technical characteristics of the boilers are listed below:
Manufacturing characteristics
User interface
Operating characteristics
- IPX4 D 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 ef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 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 draining tap
- Stainless steel plate DHW heat exchanger (KC)
- Motorized deviating valve (KC)
- DHW priority ow switch (KC)
- DHW ow limiting device: 13 liter/min (KC 24), 14 liter/
min (KC 28), 16 liter/min (KC 32)
- Boiler mode selector: OFF, RESET, WINTER, SUMMER, ANTI-
FREEZE
- CH temperature adjusting switch: 20/78 °C (standard range), or
20/45 °C (reduced range)
- DHW temperature adjusting switch (KC): 35/57 °C
- CH water pressure gauge
- Liquid crystal display (LCD) showing the boiler operating status
- CH mode electronic ame modulation, timer controlled ame
rising ramp (50 seconds)
- DHW mode electronic ame modulation (KC and KR with
external cylinder)
- DHW priority function (KC and KR with external cylinder)
- Flow anti-freeze function: ON at 5 °C; OFF at 30 °C or after 15
minutes operation when CH water > 5 °C
- DHW anti-freeze function (KC): ON at 5 °C; OFF at 10 °C or
after 15 minutes operation when DHW temperature > 5°C
- External cylinder anti-freeze 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 ame spread function
- Anti-cycling device: 240 seconds standard range, 120 seconds
reduced range
- Pump over run function in CH mode, anti-freeze and chimney
sweep mode: 180 seconds
- Pump over run function in DHW supply mode (KC and KR with
external cylinder): 30 seconds
- Pump overrun function for CH temperature > 85 °C: 30
seconds
- Fan over run function following operation: 10 seconds
- Fan over run function for CH temperature > 95 °C
- Pump (KC and KR) and deviating valve (KC) anti-blocking
function: 180 seconds operation after hours of non operation
- Ready for connection to a room thermostat (optional
equipment)
- Ready for connection to an external probe (manufacturer
delivered optional equipment)
- Ready for serving different zones (manufacturer delivered
equipment)

16
3.2. Dimensions
pic. 5
S Condensate drain
G Gas intake
SI Inspection trap plug
F CH system ow
DHW Domestic hot water draw off (KC model only)
CWI Cold water inlet (KC model only)
SV 3-bar safety valve drain cock
R CH system return
RS Drain cock
Bottom view Top view
139,5
135 148
90
90 77
325
750
450
138
177
56 98 75 98 80
71
43
46
G
F
CWI
R
S
DHW
SI
SV
RS

17
3.3 Layout
Primary heat
exchanger
Expansion
vessel
Detection
electrode
Muffler
Automatic
air vent
Circulation
pump
Gas valve
3-bar safety
valve
Electronic ignition circuit board
Water pressure
switch
Domestic cold
water flow switch
d.h.w. sensor
d.h.w. heat
exchanger
Condensate
drain trap
Electric van
Safety
thermostat
Heating
sensor
Ignition
electrode
Burner unit
Primary fluid
flow meter
pic. 6

18
3.4 Hydraulic layouts
pic. 7
DHW CWI RFGS
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 thermostat on discharge duct
13. Flue gas thermostat on exchanger
14. Flame sensing electrode
15. Expansion vessel
16. Fan management probe
17. Air purging device
18. Pump
19. 3 bar safety valve
20. Unloading tap
21. Flow limiting device
22. Water pressure switch
23. Domestic cold water ow meter with lter
24. Secondary plate exchanger
25. DHW probe
26. Automatic by-pass
27. Motorized 3-way valve
S Condensate drain
G Gas intake
F CH system ow
DHW DHW ow
CWI 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 thermostat on discharge duct
13. Flue gas thermostat on exchanger
14. Flame sensing electrode
15. Expansion vessel
16. Fan management probe
17. Air purging device
18. Pump
19. 3 bar safety valve
20. Unloading tap
21. Water pressure switch
22. Automatic by-pass
S Condensate drain
G Gas intake
F CH system ow
R CH system return
pic. 8
FS G R

19
3.5 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
Ø
[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
Ø
[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
Ø
[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
Function Max. CH
input [kW]
CH output
(80-60 °C)
[kW]
CH output
(50-30 °C)
[kW]
Gas mains
pressure
[mbar]
Diaphragm
Ø
[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 model adjustment rates
KR 28
Function Max. CH
input [kW]
CH output
(80-60 °C)
[kW]
CH output
(50-30 °C)
[kW]
Gas mains
pressure
[mbar]
Diaphragm
Ø
[mm]
Flue gas CO2
[%]
min max min max
Methane gas G20 26.2 5.4 25.55 6.1 27.4 20 7.2 8.8 ÷ 9.1
Propane gas G31 26.2 5.4 25.55 6.1 27.4 37 5.3 9.8 ÷ 10.1
Table 7 - KR 28 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]
Diaphragm
Ø
[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 model adjustment rates

20
3.6 General characteristics
KC model
KC 24 KC 28 KC 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 specific flow rate (ΔT 30K) 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 (*) ft3/h 88.6 97.9 117.4
Propane gas consumption at maximum CH input ft3/h 34.3 37.9 45.4
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 model general specications
(*) 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
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 (Net) (60/80°C) % 97.5 - -
Maximum heat output efficiency rating (Net)(30/50°C) % 104.8 - -
Minimum heat output efficiency rating (Net) (60/80°C) % - 95.7 -
Minimum heat output efficiency rating (Net) (30/50°C) % - 106.9 -
30% heat output efficiency rating % - - 109.1
Efficiency rating (according to 92/42/CE) -
SEDBUK classification -A(90.0 %)
NOx emission class - 5
Table 10 - KC 24 model combustion rates
KC 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 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 (Net) (60/80°C) % 97.53 - -
Maximum heat output efficiency rating (Net)(30/50°C) % 105.4 - -
Minimum heat output efficiency rating (Net) (60/80°C) % - 95.5 -
Minimum heat output efficiency rating (Net) (30/50°C) % - 106.7 -
30% heat output efficiency rating % - - 108.9
Efficiency rating (according to 92/42/CE) -
SEDBUK classification -A(90.0 %)
NOx emission class - 5
Table 11 - KC 28 model combustion rates