Fondital KR 55 Instructions for use

IST 03 C 000 - 01
INSTALLATION
USE AND MAINTENANCE
TAHITI CONDENSING
KR 55 - KR 85
GB

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Dear Customer,
Thank you for choosing and buying one of our boilers. Please read these instructions carefully. They will enable you to install,
operate, and service the equipment properly.
Any maintenance and repair operations must be carried by one of our fully qualied and Authorized Service Centres.

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General information for fitters, maintenance technicians and users
This INSTRUCTION MANUAL, which is an integral and indispensable part of the product, must be handed over to the user by the
installer and must be kept in a safe place for future reference. The manual must accompany the boiler should it be sold or its possession
transferred. Following installation, the tter is to advise the user about boiler operation and the safety devices.
This boiler is designed for connection to a central heating system.
Any other use is considered incorrect and therefore dangerous.
The boiler must be installed by qualied personnel, in compliance with the 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, or resulting from failure to follow the manufacturer’s instructions will relieve
the manufacturer of all contractual and extra-contractual liability.
Before installing the boiler, check that the technical data correspond to the requirements for correct use within the system.
Check that the boiler is intact and has not been damaged during transport and handling: do not install equipment which is damaged or
faulty.
Do not obstruct the air intakes.
Only original accessories supplied by the manufacturer must be used.
All the packaging materials can be recycled and should be disposed of accordingly.
Keep the packaging out of the reach of children as it can cause a hazard.
In the event of failure or faulty operation, switch off the boiler. Do not attempt to make repairs; contact a qualied technician.
Manufacturer-approved and supplied parts must be used for all repairs to the boiler.
Failure to comply with the above requirements may affect the safety of the boiler and endanger people, animals and property.
In order to guarantee efcient and correct operation of the equipment, the manufacturer recommends that the boiler be serviced and
repaired by one of its Authorized Service Centre.
Routine boiler maintenance should be performed according to the schedule in the relevant section of this manual. Appropriate boiler
maintenance ensures efcient operation, preservation of the environment, and safety for people, animals and property. Incorrect or
irregular maintenance can cause a hazard for people, animals and property.
Any maintenance and repair operations must be carried by one of our fully qualied Authorized Service Centres.
In the event of long periods of inactivity, disconnect the boiler from power mains and close the gas tap.
Warning! When power mains are disconnected, the boiler’s electronic anti-frost function will be deactivated.
Anti-freeze should be added if there is a risk of freezing. Use specic anti-freeze products suitable for multi-metal heating systems.
It is not advisable to empty the system as this may result in damage.
If you smell gas:
• do not turn on or off electric switches and do not turn on electric appliances;
• do not ignite ames and do not smoke;
• close the main gas tap;
• open doors and windows;
• contact a Service Centre, a qualied installer or the gas supply company.
Never use ames to detect gas leaks.
The boiler is designed for installation in the country indicated on the rating plate. Installation in any other country may be source of
danger for people, animals and objects.
The Manufacturer cannot be held contractually or extra-contractually liable in the event of failure to comply with the above.

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TABLE OF CONTENTS
General information for fitters, maintenance technician and user pag. 3
1. User instructions pag. 7
1.1. Control panel pag. 7
1.2. LCD pag. 8
1.3. Boiler status – Message display pag. 9
1.4. Operating the boiler pag. 10
1.4.1. Switching on the boiler pag. 10
1.4.2. CH function pag. 10
1.4.3. DHW function pag. 11
1.4.4. ANTI-FREEZE function pag. 12
1.4.5. PUMP ANTI-SHUTDOWN function pag. 12
1.4.6. Operation with Remote Control (optional) pag. 13
1.4.7. Operation with an external probe (optional) pag. 14
1.5. Boiler shutdown pag. 14
1.5.1. Burner shutdown pag. 15
1.5.2. Shutdown due to overheating pag. 15
1.5.3. Shutdown due to air/ue gas system malfunction pag. 15
1.5.4. Shutdown due to a water circulation malfunction pag. 15
1.5.5. Shutdown for fan malfunction pag. 16
1.5.6. Alarm due to temperature probe malfunction pag. 16
1.5.7. Alarm due to (optional) remote control connection malfunction pag. 16
1.5.8. Alarm due to (optional) external probe malfunction pag. 16
1.6. Maintenance pag. 16
1.7. Notes for the user pag. 17
2. Technical features and dimensions pag. 18
2.1. Technical features pag. 18
2.2. Dimensions of the KR 55 pag. 19
2.3. Dimensions of the KR 85 pag. 20
2.4. Main components for KR 55 pag. 21
2.4. Main components for KR 85 pag. 22
2.4. Operating data pag. 23
2.7. General characteristics pag. 24
2.8. Pumping head pag. 26
3. Instructions for the tter pag. 27
3.1. Installation standards pag. 27
3.2. Installation pag. 27
3.2.1. Packaging pag. 27
3.2.2 Choosing where to install the boiler pag. 27
3.2.3. Positioning the boiler pag. 27
3.2.4. Installing the boiler pag. 29
3.2.5. Boiler room ventilation pag. 29
3.2.6. Air intale and ue gas discharge system pag. 30
3.2.6.1. Conguration of air intake and ue gas discharge pipes pag. 31
3.2.6.2. Air intake and ue gas discharge conguration – model KR 55 pag. 32
3.2.6.3. Air intake and ue gas discharge conguration – model KR 85 pag. 33
3.2.7. Testing combustion efciency pag. 34
3.2.7.1. Chimney-sweep function pag. 34
3.2.7.2. Measurement procedure pag. 34
3.2.8. Connecting to the gas mains pag. 34
3.2.9. Plumbing connections pag. 36
3.2.10. Power mains connection pag. 36
3.2.11. Selecting the CH operating range pag. 37
3.2.12. Connecting the ambient thermostat (optional) pag. 37
3.2.13. Connecting the OpenTherm remote control (optional) pag. 37
3.2.14. Connecting to the external probe (optional) and sliding temperature operation pag. 39
3.3. Filling the system pag. 40
3.4. Starting the boiler pag. 41
3.4.1. Preliminary checks pag. 41
3.4.2. Switching on and off pag. 41
3.5. Wiring diagram pag. 42
3.6. Adapting to other gases and regulating the burner pag. 44
3.6.1. Switching from METHANE to PROPANE pag. 44
3.6.3. Regulating the burner pag. 44
4. Testing the boiler pag. 46
4.1. Preliminary checks pag. 46
4.2. Switching the boiler on and off pag. 46
5. Maintenance pag. 46
5.1. Maintenance schedule pag. 46
5.2. Combustion analysis pag. 47
6. Toubleshooting pag. 48

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LIST OF FIGURES
Fig. 1 - Control panel pag. 6
Fig. 2 - LCD pag. 7
Fig. 3 - Fictitious ambient temperature regulation pag. 11
Fig. 4 – Thermoregulation curves pag. 11
Fig. 5 - Filling tap pag. 12
Fig. 6 - KR 55 Dimensions pag. 15
Fig. 7 - KR 85 Dimensions pag. 16
Fig. 8 – Main components of the KR 55 pag. 17
Fig. 9 – Main components of the KR 85 pag. 18
Fig. 10 – Head curves to the KR 55 system pag. 20
Fig. 11 – Head curves to the KR 85 system pag. 20
Fig. 12 - Installation template pag. 22
Fig. 13 - Installation examples pag. 24
Fig. 14 - Boiler casing opening pag. 27
Fig. 15 – Chimney-sweep function pag. 27
Fig. 16 - Air intake and ue gas discharge tower pag. 28
Fig. 17 - Openings for combustion efciency measurement pag. 28
Fig. 18 - Gas mains connection pag. 28
Fig. 19 - Thermoregulation trimmer pag. 32
Fig. 20 - Central heating curves with external probe operation pag. 32
Fig. 21A - Wiring diagram for KR 55 pag. 34
Fig. 21B - Wiring diagram for KR 85 pag. 35
Fig. 22 - Adaptation to other gas types for KR 55 pag. 37
Fig. 23 - Adaptation to other gas types for KR 85 pag. 37
Fig. 24 - Gas valve regulation for KR 55 pag. 37
Fig. 25 - Gas valve regulation for KR 85 pag. 37
LIST OF TABLE
Table 1 - Boiler Status-Message Display with normal operation pag. 8
Table 2 - Boiler status-Message display with malfunction pag. 8
Table 3 - Calibration data for KR 55 pag. 19
Table 4 - Calibration data for KR 85 pag. 19
Table 5 - General specifications pag. 19
Table 6 – Combustion data for KR 55 pag. 19
Table 7 – Combustion data for KR 85 pag. 19
Table 8 - Burner ignition temperatures pag. 30
Table 9 – Limit values for TSP parameters and default values for each boiler type (TSP0) pag. 31
Table 10 – Displayable TSP parameters (not modifiable from remote control) pag. 31
Table 11 - Relation between temperature and nominal resistance of the temperature probe pag. 36
Table 12 - CO2 rates pag. 37

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1. User instructions
1.1. Control panel
1. Liquid crystal display (LCD)
The LCD displays the boiler status and operating data (Fig. 2).
2. Boiler function selector
With the selector on RESET the boiler restarts after activation of the burner shutdown device.
With the selector on OFF, the boiler is in stand-by mode, with the heating and hot water functions disabled.
With the selector on SUMMER the boiler is ready to produce domestic hot water only, provided it is connected to a separate water
heater. If the boiler is not connected to a separate water heater, this position is equivalent to ANTI-FREEZE .
With the selector on INVERNO the boiler is ready for both heating and domestic hot water production.
La preparazione dell’acqua calda sanitaria è attiva solo se la caldaia è collegata ad un sistema di preparazione dell’acqua calda sanitaria
esterno.
Hot water is only provided if the boiler is connected to a separate water heater.
With the selector on ANTI-FREEZE , only the anti-freeze function is enabled; the CH and DHW functions are disabled.
3. DHW temperature regulator
If the boiler is connected to a separate water heater, this regulator is used to switch the water heater on and off.
If the water heater has an NTC probe (10 kΩ @ ß=3435; refer to the water heater handbook), this is used to regulate the water temperate
in the range 35-65°C.
If the boiler is not connected to a separate water heater, this regulator has no effect on boiler operation.
4. CH water temperature regulator
This is used to select the temperature of the water in the heating system in the range 20-45°C or 20-78°C.
5. Water pressure gauge
This shows the pressure of the water in the heating system.
fig. 1
1 2 3 4 5

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

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1.3. Boiler status – Message display
Normal operation
Boiler selector on OFF
Boiler selector on ANTI-FREEZE
Boiler selector on SUMMER or WINTER
No function active
The flow water temperature is displayed
Boiler selector on SUMMER or WINTER
DHW system enabled (*)
The flow water temperature is displayed
Boiler selector on WINTER
CH function active
The flow water temperature is displayed
Boiler selector on SUMMER or WINTER
Water heater enabled, no function active (*)
The flow water temperature is displayed
Table 1 – Boiler Status-Message Display with normal operation
(*) If the boiler is connected to a separate water heater.
Malfunction
Boiler not powered on
Boiler shutdown due to flame absence
Boiler shutdown due to safety thermostat activation
Boiler shutdown due to flue gas thermostat activation
CH probe failure
Water heater probe fault
Only if the boiler is connected to a separate water heater (optional) with an NTC probe
(10 kΩ @ ß=3435; refer to the water heater handbook).
Low primary fluid circulation alarm
(pump ON – flow switch OPEN)
Allarme circolazione fluido primario insufficiente
(pompa OFF – flussostato CLOSE)
Low primary fluid circulation alarm (pump OFF – flow switch CLOSED)
Remote control connection failure
External probe failure
Table 2 - Boiler status-Message display with malfunction

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1.4. Operating the boiler
1.4.1. Switching on the boiler
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 master switch external to the boiler; the LCD shows and indicates the active function (see Table 1).
- Select boiler operation mode via selector 2 (Fig. 1): OFF/SUMMER/WINTER/ANTI-FREEZE.
- Set the desired CH temperature (§ 1.4.2.).
- If the boiler is connected to a separate water heater, set the desired DHW temperature (§ 1.4.3.).
- Set the desired ambient temperature by means of the ambient thermostat in the premises (optional).
IMPORTANT
When starting up the boiler for the first time or it has not been used for a long period of time, particularly when it is propane-
fired, ignition may be difficult and the boiler may shut down a few times.
Resume boiler operation by turning selector 2 (Fig. 1) to the reset position for a few seconds then back to the desired position.
If the boiler still does not ignite after several attempts, it needs to be serviced by an Authorised Service Centre or a qualified
service engineer.
1.4.2. CH function
Set the desired CH water temperature on knob 4 (Fig. 1).
The CH water temperature range depends on the selected operating range:
- standard range: from 20°C to 78°C (from full anticlockwise to full clockwise position).
- reduced range: from 20°C to 45°C (from full anticlockwise to full clockwise position).
The temperature range must be set by the tter or an Authorized Service Centre (§ 3.2.11. 9).
During temperature setting, the CH symbol on the LCD ashes and the CH setting is displayed.
When the CH system requests heat, the LCD shows the (stable) CH symbol and the CH water tempe-
rature.
When the CH system requests heat, the LCD shows the (stable) CH symbol and the CH water temperature.
The burner symbol only shows when the burner is in operation.
To prevent the boiler from switching on and off frequently in CH mode, it is programmed with a delay time
between subsequent ignitions, which depends on the selected operating range:
- standard range: 4 minutes;
- reduced range: 2 minutes.
Should the water temperature in the system fall below the default value (§ 3.2.11.), the delay time is zeroed and the boiler re-ignited.
1.4.3. DHW function
Domestic hot water function is only enabled if connected to a separate water heater (optional).
The DHW function always has priority over the CH function.
Enabling/disabling the water heater
Il bollitore esterno (optional) può essere abilitato o disabilitato alla produzione di acqua calda sanitaria tramite il regolatore 3.
The separate water heater (optional) can be enabled or disabled via knob 3.
If the water heater active symbol is not displayed, turn knob 3 fully anticlockwise and the symbol will appear.
Then turn it clockwise until a temperature of at least 40°C is displayed. To disable the water heater, turn knob 3 fully anticlockwise until
the symbol disappears and then clockwise until a temperature of at least 40°C is displayed.
When you turn knob 3, the DHW symbol ashes on the display.
.

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Regulating the DHW temperature
If the water heater has an NTC probe (10 kΩ @ β=3435; refer to the water heater handbook), the temperature setting range is 35-65°C
(from the fully anticlockwise to the fully clockwise position on knob 3). During temperature setting, the
DHW symbol ashes on the display and the DHW temperature setting is displayed.
It is advisable to set a temperature of at least 40°C to allow the system to operate efficiently.
If the water heater has a thermostat probe, the DHW temperature must be set on the water heater (refer to water heater handbook). Knob
3 has no effect on this conguration, except to enable/disable the water heater as described above.
With the water heater enabled, it is always advisable to set knob 3 to at least 40°C.
When the DHW system requests water, the LCD shows the DHW symbol (stable) and the instant CH water temperature.
The burner symbol only shows when the burner is in operation.
1.4.4. ANTI-FREEZE function
The boiler is tted with an anti-freeze protection system, which works when the following functions are
enabled: SUMMER, WINTER and ANTI-FREEZE.
When the CH temperature sensor measures 5°C, the boiler switches on and stays at the minimum heat output until it reaches 30°C or 15
minutes have elapsed. The pump continues to operate even if the boiler shuts down.
Anti-freeze function protects the boiler only, not the entire CH system. The CH system must be protected by other
methods, depending on the type of installation.
The CH system can be protected effectively against freezing by means of specic anti-freeze additives suitable for use in multi-metal
systems.
It is important to check the effectiveness of the anti-freeze product periodically.
Do not use car engine anti-freeze products.
If the boiler is connected to a separate water heater with an NTC probe (10 kΩ @ β=3435; refer to the water heater handbook), when the
probe measures a temperature of 5°C in the water heater, the boiler switches on and stays at the minimum heat output until it reaches
10°C or 15 minutes have elapsed. The pump continues to operate even if the boiler shuts down.
If the boiler is connected to a separate water heater with a thermostat, the anti-freeze function does not protect the water heater. In this
case, to protect the water heater, you need to turn knob 3 on the boiler to WINTER and set a DHW water temperature on the water hea-
ter higher than 0 °C.
If the boiler shuts down, the heater is not protected against freezing.
1.4.5. PUMP ANTI-SHUTDOWN function
If:
- the boiler remains inactive,
- selector 2 (Fig. 1) is NOT in the OFF position, or
- the boiler is still connected to the mains supply,
the pump activates briey every 24 hours to keep it efcient.
1.4.6. Operation with Remote Control (optional)
The boiler can be connected to an (optional) remote control, which can be used for setting numerous parameters, including:
- boiler status
- ambient temperature
- CH water temperature
- DHW water temperature
- CH water temperature (only if connected to a separate water heater (optional) with an NTC temperature probe 10 kΩ @ ß=3435);
- switching on times for the CH system and water heater;
- boiler diagnostics display
- boiler reset
For instructions on how to connect the remote control, refer to § 3.2.13.

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Once the remote control has been installed, turn selector 2 on the boiler (Fig. 1) to WINTER.
CH and DHW functions can be enabled and disabled via the remote control.
Correct operation of the boiler and remote control are not guaranteed if selector 2 on the boiler is left on a position other than
WINTER.
Selector 2 on WINTER
Only original remote controls supplied by the manufacturer must be used.
If non-original remote controls are used, correct operation of the boiler and the remote control cannot be guaranteed.
1.4.7. Operation with an external probe (optional)
The boiler can be connected to an external temperature probe (optional).
When the external temperature has been measured, the boiler automatically regulates the CH water temperature, increasing it when the
outside temperature drops and decreasing it when it rises, which improves comfort and saves fuel (this is referred to as “sliding tempera-
ture operation”).
The CH water temperature varies according to a program in the boiler’s microprocessor.
When an external probe is installed, knob 4 (Fig. 1) loses its CH water temperature fun-
ction and becomes a fictitious ambient temperature regulator (Fig. 3) for the temperature
desired in the rooms to be heated.
During temperature setting, the fictitious ambient temperature symbol flashes and the
temperature setting is displayed.
Knob 4 in the fully anticlockwise position corresponds to a fictitious
ambient temperature of 15°C, 9 o’clock corresponds to 18°C, 12
o’clock to 25°C, 3 o’clock to 32°C and the fully clockwise position
to 35°C. To get an optimal curve, a setting of approximately 20°C is
recommended.
Figure 4 shows the curves for a fictitious ambient temperature of
20°C.
If the value is increased or decreased via knob 4, the curve shifts up and down, respectively, by the same amount.
With this setting, for example, if you select the curve corresponding to parameter 1 and the outdoor temperature is -4°C, the
flow temperature will be 50°C.
For details on sliding temperature operation mode, refer to § 3.2.14.
Only original external probes supplied by the manufacturer must be used.
If non-original external probes are used, correct operation of the boiler and the probe cannot be guaranteed.
fig. 3
15 35
32
25
18
fig. 4

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1.5. Boiler shutdown
The boiler shuts down automatically if a malfunction occurs.
Refer to Tables 1 and 2 to identify the boiler operating mode.
Refer to Table 2 and section 6 to identify possible causes of the shutdown. The troubleshooting section is at the end of this manual.
Below is a list of possible causes of the shutdown and the procedure to follow in each case.
1.5.1. Burner shutdown
If the burner shuts down as there is no ame, the burner shutdown symbol is displayed and code E01 ashes.
If this happens, proceed as follows:
• check that the gas cock is open and light a kitchen gas ring for example to check the gas supply;
• if the gas supply is normal, turn selector 2 to the reset position for a few seconds, then back to
the desired position. If after three attempts the burner still fails to ignite, contact an Authorised Service
Centre or a qualied service engineer.
If the burner shuts down frequently, there is a recurring malfunction, so contact an Authorised Service Centre or a qualied service
engineer.
1.5.2. Shutdown due to overheating
If the water temperature is too high, the boiler will shut down. The burner shutdown symbol is displayed and code E02 ashes.
Contact an Authorised Service Centre or a qualied service engineer.
1.5.3. Shutdown due to air/flue gas system malfunction
If the air/ue gas system malfunctions, the boiler shuts down. The burner shutdown symbol is displayed and code E03 (ue gas
thermostat) ashes.
Contact an Authorised Service Centre or a qualied service engineer.
1.5.4. Shutdown due to a water circulation malfunction
If the pressure or water circulation in the heating system are incorrect, the boiler shuts down. The boiler shutdown symbol is displa-
yed and code E10 or E26 ashes, according to the malfunction.
With code E10 ashing there can be two different situations:
a) the pressure gauge (5, Fig. 1) shows a pressure lower than 1 bar
Proceed as follows to restore the correct water pressure:
• Turn the lling tap (Fig. 5) anticlockwise to allow water to enter the boiler.
• Keep the tap open until the pressure gauge shows a value of 1-1.3 bar.
• Turn the tap clockwise to close it.
• Wait a minute until the malfunction disappears from the display.
If the boiler still fails to operate, contact an Authorised Service Centre or a qualified service engineer.
Make sure you close the tap carefully after filling. If you do not, when the pressure increases, the safety valve may
activate and discharge water.
b) the pressure gauge (5, Fig. 1) shows a pressure of 1-1.3 bar
Contact an Authorised Service Centre or a qualied service engineer.
2. With flashing code E26, contact an Authorised Service Centre or a qualied service engineer.
fig. 5 Filling tap

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1.5.5. Shutdown for fan malfunction
Fan operation is constantly monitored and in case of a malfunction it goes off; the boiler shutdown
symbol is displayed and code E17 ashes.
This mode is maintained until the fan recovers normal working parameters.
If the boiler should not start and remain in this mode, contact an Authorised Service Centre or a qualied service engineer.
1.5.6. Alarm due to temperature probe malfunction
If the burner shuts down due to malfunction of the temperature probes, the boiler shutdown symbol is displayed and the following
codes may ash:
• E05, CH probe: the boiler does not work;
• E12, for the heater probe (if the boiler is connected to an external optional water heater tted with NTC 10 kΩ @ß=3435 temperature
probe): the boiler operates in CH mode only.
Contact an Authorised Service Centre or a qualied service engineer.
1.5.7. Alarm due to (optional) remote control connection malfunction
The boiler recognises whether or not there is a remote control (optional). If the remote control is connec-
ted but the boiler does not receive instructions, the boiler shutdown symbol is displayed and code
E22 ashes.
The boiler will continue to operate according to the settings on the control panel (Fig. 1) and ignore the remote control settings.
Contact an Authorised Service Centre or a qualied service engineer.
1.5.8. Alarm due to (optional) external probe malfunction
If the (optional) external temperature probe malfunctions, the boiler shutdown symbol is displayed and code E23 ashes.
The boiler will continue to operate, but the sliding temperature function is disabled. The temperature of the CH water is regulated ac-
cording to the position of regulator 4 (Fig. 1), which in this case loses its function as a ctitious ambient
temperature regulator (see 1.4.7.).
Contact an Authorised Service Centre or a qualied service engineer.
1.6. Maintenance
The boiler must be serviced periodically as indicated in the relevant section of this manual.
Correct maintenance of the boiler will allow it to work efficiently, without harming the environment, and in complete safety.
Maintenance and repairs must be performed by qualified personnel.
The user is strongly advised to have the boiler serviced and repaired by one of the Manufacturer’s fully qualified and Authorised
Service Centres.
Refer to section 5 for Maintenance instructions.
The only thing the user should do is clean the outside of the boiler using ordinary cleaning products. Do not use water.
1.7. Notes for the user
The user may only access parts of the boiler that can be reached without using special equipment or tools. The user is
not authorised to remove the boiler casing or to operate on any internal parts.
No one, including qualified personnel, is authorised to modify the boiler.
The manufacturer cannot be held liable for damage or injury due to tampering of the boiler or improper intervention.
If the boiler remains inactive and the power supply is switched off for a long time, it may be necessary to reset the pump.
This involves removing the casing and accessing internal parts, so it must only be done by suitably qualified personnel.
Pump failure can be avoided by adding to the water filming additives suitable for multi-metal systems.

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2. Technical features and dimensions
2.1. Technical features
The boiler is equipped with a fully pre-mixed gas burner. All models are equipped with electronic ignition and an ionization ame
sensing device.
The following models are available:
KR 55: condensing boiler with sealed chamber and forced draught, supplying CH water, 55kW
KR 85: condensing boiler with sealed chamber and forced draught, supplying CH water, 85kW
The boilers meet applicable laws in force in the country of destination, which is stated on the rating plate.
If the boiler is installed in a country other than the one specied, it may be dangerous for people, animals and objects.
The main technical features of the boilers are listed below:
Construction features
- IPX4D electrically protected control panel
- Electronic safety board and integrated modulation
- Electronic ignition via separate igniter and ionization ame detection
- Stainless steel, fully pre-mixed burner
- Stainless steel mono-thermal, high-efciency heat exchanger
with deaerator
- Twin shutter, modulating gas valve with constant air/gas ratio
- Electronically-controlled modulating ue gas discharge fan
- Three-speed pump with built-in deaerator
- Air separator with deaerator
- Differential pressure switch, preventing incorrect water circulation
in the CH system
- Minimum ow switch detecting no water in the CH system.
- CH temperature probe
- Safety thermostat
- Flue gas thermostats
- Filling tap
User interface
- Liquid crystal display showing the boiler operating status
- Mode selector: OFF, RESET, WINTER, SUMMER and
ANTI-FREEZE
- CH water temperature regulator: 20-78°C (standard range) or
20-45 °C (reduced range)
- DHW water temperature regulator: 35-65°C (if connected to a
water heater)
- Water pressure gauge
Operating features
- Electronic ame modulation in CH mode with timer-controlled
rising ramp (50 seconds)
- Flow anti-freeze function: ON at 5°C; OFF at 30°C or after 15
minutes of operation if CH temperature >5°C.
- Water heater anti-freeze function (if connected to a separate wa
ter heater): ON at 5°C; OFF at 10°C or after 15 minutes of opera
tion if water temperature in the heater >5°C.
- Anti-legionella function (if connected to a separate water heater
with an NTC 10 kΩ @ ß=3435 probe.
- Timer-controlled chimney-sweep function: 15 minutes
- Ignition ame propagation function
- Timer-controlled ambient thermostat: 240 seconds with ow
temperature >40°C
- Pump post-circulation function in CH, anti-freeze and chimney-
sweep modes
- Post-ventilation safety function: ON at 95°C, OFF at 90°C.
- Pump anti-shutdown function: 180-second operation after 24
hours of boiler inactivity
- Provision for connection to a ambient thermostat (optional)
- Provision for operation with an external probe (optional, supplied
by the manufacturer)
- Provision for operation with an OpenTerm remote control (optio
nal, supplied by the manufacturer).

15
2.2. Dimensions of the KR 55
fig. 6
S Condensate drain
F Water mains intake (1/2’’)
G Gas intake (3/4’’)
SI Condensate trap
M CH system ow (1’’)
RC Filling tap
R CH system return (1’’)
450
750 3050
43 56 173 98 80
220.5
12762
14813589 78
534
S
SI
G
MF
R
RC
Aspirazione aria
scarico fumi
Ø 100/60 mm
Aspirazione aria
Ø 80 mm
View from below
View from above

16
2.3. Dimensions of the KR 85
750
450
50 42
89 135 148 78
12762
534
43 56 173 98 80
220.5
S
SI
G
MF
R
RC
Scarico fumi
Ø 100 mm
Aspirazione aria
Ø 80 mm
fig. 7
S Condensate drain
F Water mains intake (1/2’’)
G Gas intake (3/4’’)
SI Condensate trap
M CH system ow (1’’)
RC Filling tap
R CH system return (1’’)
View from below View from above

17
2.4. Main components for KR 55
fig. 8
1
12
3
9
8
18
16
10
2
19 20
7
5
6
11
13
17
15
14
4
21
1 Control panel
2 Heat exchanger
3 Flue gas fan
4 Air separator
5 Deaerator on heat exchanger
6 CH temperature probe
7 Flue gas thermostat
8 Inspection trap plug
9 Condensate drain pipe
10 Pre-mixing burner
11 Twin differential/minimum water pressure switch
12 Gas valve
13 Safety thermostat
14 Circulating pump
15 Deaerator on air separator
16 Ignition electrode
17 Detection electrode
18 Air/gas mixer
19 Air/ue gas test intake
20 Air/ue gas suction tower
21 Corrugated pipe

18
2.5. Componenti principali KR 85
1
9
8
3
12
4
15
14
13
17
11
6
5
7
21
20
19
2
16
10
18
1 Control panel
2 Heat exchanger
3 Flue gas fan
4 Air separator
5 Deaerator on heat exchanger
6 CH temperature probe
7 Flue gas thermostat
8 Inspection trap plug
9 Condensate drain pipe
10 Pre-mixing burner
11 Twin differential/minimum water pressure switch
12 Gas valve
13 Safety thermostat
14 Circulating pump
15 Deaertator on air separator
16 Ignition electrode
17 Detection electrode
18 Air/gas mixer
19 Air/ue gas test intake
20 Air/ue gas suction tower
21 Corrugated pipe
fig. 9

19
2.6. Dati di funzionamento
Burner pressures must be veried after a three minute boiler operation time.
KR 55
Function
Max. CH
input
(kW)
CH
output
(80-60°C)
[kW]
CH
output
(50-30°C)
[kW]
Gas mains
pressure
[mbar]
Diaphragm dia-
meter
[mm]
Flue gas
CO2
[%]
min max min max
Methane Gas G20 55,0 14,1 53,5 15,7 58,8 20 8,2 8,8 ÷ 9,1
Propane Gas G31 55,0 14,1 53,5 15,7 58,8 37 5,9 9,8 ÷ 10,1
Table 3 – Calibration data for KR 55
KR 85
Function
Max. CH
input
(kW)
CH
output
(80-60°C)
[kW]
CH
output
(50-30°C)
[kW]
Gas mains
pressure
[mbar]
Diaphragm dia-
meter
[mm]
Flue gas
CO2
[%]
min max min max
Methane Gas G20 85,0 20,3 82,7 22,6 90,4 20 10,3 8,8 ÷ 9,1
Propane Gas G31 85,0 20,3 82,7 22,6 90,4 37 7,9 9,8 ÷ 10,1
Table 4 – Calibration data for KR 85
2.7. General characteristics
KR 55 KR 85
Category - II2H3P II2H3P
CH minimum pressure bar 0,5 0,5
CH maximum pressure bar 5 5
CH maximum working temperature °C 83 83
DHW maximum working temperature (*) °C 65 65
Methane gas consumption at max. flow (**) m3/h 5,82 9,00
Propane gas consumption at max. ow kg/h 4,26 6,59
Power supply (voltage ~ frequency) V ~ Hz 230 ~ 50 230 ~ 50
Maximum input power W 245 245
Index of protection IP X4D X4D
Table 5 – General Data
(*) If connected to a water heater with NTC probe 10 kΩ @ ß=3435
(**) Value referred to 15 °C - 1013 mbar
KR 55 Pmax Pmin 30% heat output
Casing heat loss with burner on % 0,46 0,83 -
Casing heat loss with burner off % 0,36
Chimney heat loss with burner on % 2,04 1,89 -
Flue gas system mass ow rate g/s 25,1 6,6 -
Flue gas/air temperature °C 44 39 -
Prevalenza residua disponibile Pa 290 23 -
Maximum heat output efciency rating (60/80°C) % 97,3 - -
Maximum heat output efciency rating (30/50°C) % 107,0 - -
Minimum heat output efciency rating (60/80°C) % - 97,0 -
Minimum heat output efciency rating (30/50°C) % - 108,1 -
Efciency rating (according to 92/42/CEE) % - - 108,9
NOx emission class -
Casing heat loss with burner on - 5
Table 6 – Combustion data for KR 55
KR 85 Pmax Pmin 30% heat output
Casing heat loss with burner on % 0,30 0,93 -
Casing heat loss with burner off % 0,48
Chimney heat loss with burner on % 2,20 1,79 -
Flue gas system mass ow rate g/s 38,7 9,6 -
Flue gas/air temperature °C 47 36 -
Prevalenza residua disponibile Pa 240 19 -
Maximum heat output efciency rating (60/80°C) % 97,3 - -
Maximum heat output efciency rating (30/50°C) % 106,4 - -
Minimum heat output efciency rating (60/80°C) % - 97,3 -
Minimum heat output efciency rating (30/50°C) % - 107,7 -
30% heat output efciency rating % - - 108,5
Efciency rating (according to 92/42/CEE) -
Casing heat loss with burner on - 5
Table 7 – Combustion data for KR 85

20
2.8. Pumping head
fig. 10
V1
V2
V3
V1 Pump speed I (min)
V2 Pump speed II
V3 Pump speed III (max)
V1
V2
V3
V1 Pump speed I (min)
V2 Pump speed II
V3 Pump speed III (max)
fig. 11
KR 55
KR 85