Fondital Nias Dual BTFS 24 User manual

DIDACTIC MANUAL
FAMILY: Wall-hung boilers
GROUP: Aqua Premium (compact
with excludable water tank)
MODELS: Nias Dual BTFS
Libra Dual BTFS
CODE: AST 14 C152/00
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1st Edition, March 2006

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2 AST 14 C 152/00
Contents
CHAPTER 01
GENERAL INFORMATION 1.1- Models
1.2 – Dimensions
1.3 –Complete view and components ___________________Page 03
CHAPTER 02
OPERATION 2.1 – Operation criteria
2.2 – Control panel
2.3 – Regulation fields
2.4 –Pump anti-blockage and anti-freeze system ___________________Page 06
CHAPTER 03
CHARACTERISTICS AND TECHNICAL DATA 3.1 –Construction characteristics
3.2 – Operating characteristics
3.3 – Operational data
3.4 – Technical data ___________________Page 13
CHAPTER 04
GAS VALVE AND CONVERSIONS 4.1 – Gas valve SIT 845
4.2 – Gas conversions
4.3 – Gas valve regulation
4.4 –Chimney sweep function ___________________Page 16
CHAPTER 05
HYDRAULIC GROUP 5.1 – Complete hydraulicgroup
5.2 –Secondaryplate heat exchanger
5.3 –Three way valve
5.4 –2 wayinterception valve ___________________Page 19
CHAPTER 06
ELECTRONICS 6.1 – Electronicboard - jumper
6.2 –Electronic board –ignition phase
6.3 –Electronic board –diagram
6.4 – Relay board
6.5 –Remote control
6.6 –Sliding temperaturefunction ___________________Page 21
CHAPTER 07
FLUE GAS SYSTEMS 7.1 –Coaxial pipes 100/60mm
7.2 –Split pipes 80mm
7.3 –Positioning of terminals ___________________Page 24
CHAPTER 08
MAINTENANCE 8.1 – Standards and recommendations
8.2 – Maintenance schedule ___________________Page 26
CHAPTER 09
TROUBLESHOOTING 9.1 – Table ___________________Page 27

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3 AST 14 C 152/00
CHP.1
GENERAL INFORMATION
1.1 MODELS
NIAS DUAL BTFS INDOOR
Instantaneous boiler, elevated DHW production with 25 litre water tank, excludable
bythe user. Fondital version. Model to be installed inside the apartment.
Output: 24, 28 and 32 kW
LIBRADUAL BTFS INDOOR
Instantaneous boiler, elevated DHW production with 25 litre water tank, excludable
bythe user. Nova Florida version. Model to be installed inside the apartment.
Output: 24, 28 and 32 kW
NIAS DUAL BTFS ENCASED
Instantaneous boiler, elevated DHW production with 25 litre water tank, excludable
by the user. Fondital version. Model with reduced depth placed inside a metal
casing to be built into the external wall.
Output: 24, 28 and 32 kW
LIBRADUAL BTFS ENCASED
Instantaneous boiler, elevated DHW production with 25 litre water tank, excludable
by the user. Nova Florida version. Model with reduced depth placed inside a metal
casing to be built into the external wall.
Output: 24, 28 and 32 kW
FOR ALL NIAS AND LIBRA DUAL BOILERS:
Elevated output (HEATING): Standard ref. 92/42/CEE
Elevated output (DOMESTIC HOT WATER): Standard ref. prEN 13203
Continuous modulation in DHW and heating
DHW expansion vessel: 2 Litres
Heat exchanger DHW: 22 plates for 24kW and 26 plates for 28 and 32kW
Production Domestic Hot Water (l/10 mins): 160 for 24kw with t 30°C
180 for 28kw with t 30°C
200 for 32kw with t 30°C

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4 AST 14 C 152/00
1.2 DIMENSIONS
Nias and Libra Dual BTFS indoor
ELECTRIC PROTECTION: IP44
Nias and Libra Dual BTFS in-wall
ELECTRIC PROTECTION: IXP5D

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5 AST 14 C 152/00
1.3 COMPLETE VIEW and COMPONENTS
DHW plate
heat exchanger
Hydraulic
group
DHW plate
Control board Electronic
board
Flow pressare
switch
CH pump
Flow meter
Safety valve
DHW pump
Two-way
valve
Ignition
transformer
CH
expansion
vessel
DHW
expansion
vessel
pressure
switch
Fan
Air purging
valve
Flue gas
hood
Mono-
thermal
exchanger
Burner
Electrodes
Gas valve
Water tank

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6 AST 14 C 152/00
CHP.2
OPERATION
2.1 OPERATION CRITERIA
WATER TANK
The boiler heats up automatically the water tank in a very short time when the aqua
premium turns on.
The system keeps the water in the tank at 10°C higher than the set DHW
temperature.
WATER TANK TIMES
24 kW – about 6 minutes and 30seconds
28 kW – about 5 minutes and 30seconds
32 kW – about 4 minutes and 30seconds
WATER TANK TYPE
Stratified water tank
Internal glass finish
Capacity: 25 litres
Losses: about 1°C / hour for built-in – about 1°C / 3 hours for indoor
Flow meter
Flow Return

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7 AST 14 C 152/00
When the water tank switch is off, the DHW pump and the two way interception valve are
not active, in this situation the boiler operates as astandard instantaneous boiler:
HEATING MODE
DHW MODE (INSTANTANEOUS)
ReturnFlow
Flow meter
ReturnFlow
Flow meter

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8 AST 14 C 152/00
When the water tank switch is on, the DHW pump and the two way interception valve are
active, the boiler can utilise the hot water present in the water tank. This process can take
place in two ways depending on the water flow to the tap requested by the end user:
reduced withdrawal and premium withdrawal.
DHW MODE (AQUA PREMIUM WITH REDUCED WITHDRAWAL)
This occurs when the end-user requests a quantity of DHW less than the quantity
permitted by a flow regulator placed after the plate heat exchanger (8l/min for
24kW, 10l/min for 28 Kw and 12l/min for the model with 32 Kw output). Example: if
the end-user requires less than 8 litres per minute (24kW), the remaining quantity of
hot water produced by the plate heat exchanger enters the water tank and in turn
mixes at the outlet with the water in system thus raising the inlet temperature at the
DHW heat exchanger.
The system is particularly useful where there are particularly low temperatures at
the inlet to the water system and/or in order to achieve water at an ideal
temperature more rapidlyfor use.
Flow meter
ReturnFlow

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9 AST 14 C 152/00
DHW MODE (AQUA PREMIUM WITH ELEVATED WITHDRAWAL)
This occurs when the end-user requests a quantity of DHW greater than the
quantity permitted by a flow regulator placed after the plate heat exchanger (8l/min
for 24kW, 10l/min for 28 Kw and 12l/min for the model with 32 Kw output). By
utilising the hot water in the water tank (at higher temperatures) together with the
production of domestic hot water produced by the plate heat exchanger of the
appliance, the user is in a position tomake use of asignificant quantity of hot water
in a determined space of time (until the stratified water tank has been completely
emptied).
The system is particularly useful where in certain times of the day it is necessary to
supply several users contemporarily (for example on the return home of workers in
the evening) without having to connect a boiler of greater capacity and size with the
same output at greater costs. It is convenient during the rest of the day because it
can be disabled with the on/off switch or programmer thus transforming itself into a
traditional instantaneous wall-hung boiler.
Flow
Flow meter
return

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10 AST 14 C 152/00
2.2 CONTROL PANEL
1 Power light (green)
2-7 Indication light (red)
8 Indication light (green)
9 Boilermodeselector – boiler reset
10 Domestic hot watersupplyknob
11 CH water temperature knob
12 Water pressure gauge
13 Aqua Premium system powerswitch
The warning lights 1-8 can indicate two different situations: inform in the case of normal
operation of the boiler or warn in the case ofmalfunctioning orshut-down of the boiler.
INDICATIONLIGHTS DURING NORMAL OPERATIONOF THE BOILER
2 3 4 5 6 7
Condition Red Red Red Red Red Red
Flow temperature 20° orless OFF OFF OFF OFF OFF OFF
Flow temperature 30° ON OFF OFF OFF OFF OFF
Flow temperature 40° OFF ON OFF OFF OFF OFF
Flow temperature 50° OFF OFF ON OFF OFF OFF
Flow temperature 60° OFF OFF OFF ON OFF OFF
Flow temperature 70° OFF OFF OFF OFF ON OFF
Flow temperature 80° OFF OFF OFF OFF OFF ON
Flow temperature 90° ormore OFF OFF OFF OFF OFF ON L
Key chart:
OFF - Led off
ON - Led on, fixed
ON L - Led on, flashing

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11 AST 14 C 152/00
WARNING LIGHTS IN THE CASE OF MALFUNCTIONING ORSHUT-DOWNOF THEBOILER
1 2 3 4 5 6 7 8
Condizione Green
Red Red Red Red Red Red Red
Flame detectionshut-down X OFF OFF OFF ON L
OFF OFF OFF
Safetythermostat shut-down X OFF ON L
OFF OFF OFF OFF OFF
Water pressureshut-down X OFF OFF OFF OFF ON L
OFF OFF
Smoke thermostat./press. shut-down
X OFF OFF ON L OFF OFF OFF OFF
Flow probemalfunction X ON L
OFF OFF OFF OFF OFF ON L
DHWprobe malfunction X ON L
OFF OFF OFF OFF OFF OFF
Water tankprobe malfunction X ONLA
OFF OFF OFF OFF OFF ONLA
Gas modulator malfunction X OFF ON L
OFF OFF OFF OFF ON L
Remotecontrol malfunction X OFF OFF ON L OFF OFF OFF ON L
Flowtemperature 90° or more X OFF OFF OFF OFF OFF ON L
X
Water tankin heating phase X X X X X X X ON
Power connection ON X X X X X X X
Key chart:
OFF - Led off
ON - Led on, fixed
ON L - Led on, flashing
ON LA - Led on, flashing alternately

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12 AST 14 C 152/00
2.3 REGULATION FIELDS
The regulation field of the heating temperature is from 35 to 78 °C.
To prevent frequent and switching off in the heating mode, the boiler has a 4 minute
waiting time betweensubsequent ignitions.
Should water temperature in thesystem fall below 40°C the waiting time is aborted and the
boiler re-ignites.
Boiler electronics always gives priorityto DHW over CH supply.
DHW temperature can be adjusted within 35 to 57 °C range.
2.4 PUMP ANTI-FREEZE AND ANTI-BLOCKAGE SYSTEM
The anti-freezing protectionsystem is active in the positions summer/winter/anti-freeze.
When the heating water temperature probe detects a water temperature below 5°C, the
boiler turns on and remains on at its minimum thermal power until the temperature of the
central heating water reaches a temperature of 30°C or at least 15 minutes have elapsed.
ATTENTION
The anti-freeze function only protects the boiler, it does not protect the entire
heating system. To protect the heating system with the boiler in the anti-freeze
position or off, utilise specific products.
When the selector is in the OFF position the anti-freeze function is not active.
The anti-freeze function also protects the water tank: when the water tank probe detects a
water temperature below 5°C, the boiler turns on and remains on at the minimum thermal
power until the temperature of the water in the water tank reaches a temperature of 10°C
or until at least 15 minutes have elapsed.
In the built-in model, for some requirements, an option is
designed in order to solve winter problems: a kit of resistances
for the protection of the connection fittings between the boiler
and the system.
Should the boilershut down, the circulation of the pump is at anyrate guaranteed.
Should the boiler remain inactive while being connected to the electricity supply, every 24
hours the circulation pump and the deviating valve are activated for 3 minutes, in order to
avoid blockage.

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13 AST 14 C 152/00
CHP.3
CHARACTERISTICS AND TECHNICAL DATA
3.1 CONSTRUCTION CHARACTERISTICS
- Mono-thermal, high output, copperheat exchanger.
- DHW Stainless steel plate heat exchanger.
- Vertical stratification 25 litre water tankwith magnesium anode.
- Three-speed CH circulation pump equipped with air-purging device.
- DHW circulator.
- Motorized cut-off valve.
- 8 litre CH expansion vessel for BTFS 24 model and 10 litre for BTFS 28 and BTFS 32 models.
- 2 litre DHW expansion vessel.
- Low water pressure switch.
- DHW priorityflow switch.
- DHW flowlimiting device (8 l/min – 24Kw, 10 l/min – 28Kw, 12 l/min – 32Kw).
- Adjustable by-pass.
- CH system loading and draining taps.
- CH water, DHW and water tanktemperature probes.
- Safetylimit thermostat.
- IP44 electricallyprotected control panel.
- Electronic safety board and integrated modulation.
- Electronicignition with separate transformer.
- Flue gas pressure switch.
- Gasvalve with double shutter.
3.2 OPERATING CHARACTERISTICS
- DHW priorityfunction.
- CH mode electronicflame modulation, timer controlled flame rising ramp (50 seconds).
- DHW mode electronic flame modulation.
- Boiler and storage tank anti-freezing function.
- Maximum heat input adjusting trimmer.
- Ignition heat input adjusting trimmer.
- Timer-controlled “chimney sweep” function (15 minutes).
- Ignition flame propagation function.
- Timer-controlled room thermostat (240 seconds when CH flow temperature >40°C).
- CH pump post-circulation function in boiler wintermode (180 seconds).
- CH pump post-circulation function after DHW production, in boiler wintermode only (6 seconds).
- DHW post-ventilation function in boiler summer mode only (6 seconds - CTFS).
- Post-ventilation safety function (ON: 95°C; OFF: 90°C - CTFS).
- Anti-blocking function for DHW pump and deviating valve (6 seconds of pump operation every 24
hours of boilerinactivity).

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14 AST 14 C 152/00
3.3 OPERATIONAL DATA
BTFS 24
Burner pressure
[mbar]
Function Max. heat
input [Kw]
Max. heat
output
[Kw]
Min. heat
output
[Kw]
Gas mains
pressure
[mbar]
Nozzle
diameter
[mm] min max
Methane Gas G20 25,5 23,8 9,5 20 1,25 2,5 13,5
Butane Gas G30 25,5 23,8 9,5 29 0,77 4,2 27,0
Propane Gas G31 25,5 23,8 9,5 37 0,77 5,5 35,7
Instantaneous DHW supply ∆t 30°C = 11,4 litres per minute
Instantaneous DHW supply t 35°C = 9,7 litres per minute
Instantaneous DHW supply t 25°C = 13,6 litres per minute
DHW supply with Aqua Premiumfunction t 30°C = 160 l/10 min
DHW supply with Aqua Premiumfunction t 25°C = 192 l/10 min
BTFS 28
Burner pressure
[mbar]
Function Max. heat
input [Kw]
Max. heat
output
[Kw]
Min. heat
output
[Kw]
Gas mains
pressure
[mbar]
Nozzle
diameter
[mm] min max
Methane Gas G20 30,5 28,4 10,0 20 1,35 1,3 11,5
Butane Gas G30 30,5 28,4 10,0 29 0,80 3,5 28,5
Propane Gas G31 30,5 28,4 10,0 37 0,80 4,5 33,0
Instantaneous DHW supply ∆t 30°C = 13, litres per minute
Instantaneous DHW supply t 35°C = 11,6 litres per minute
Instantaneous DHW supply t 25°C = 16,3 litres per minute
DHW supply with Aqua Premiumfunction t 30°C = 180 l/10 min
DHW supply with Aqua Premiumfunction t 25°C = 216 l/10 min
BTFS 32
Burner pressure
[mbar]
Function Max. heat
input [Kw]
Max. heat
output
[Kw]
Min. heat
output
[Kw]
Gas mains
pressure
[mbar]
Nozzle
diameter
[mm] min max
Methane Gas G20 33,6 31,3 12,2 20 1,40 1,7 9,2
Butane Gas G30 33,6 31,3 12,2 29 0,78 4,1 28,2
Propane Gas G31 33,6 31,3 12,2 37 0,78 5,5 34,8
Instantaneous DHW supply ∆t 30°C = 15,0 litres per minute
Instantaneous DHW supply t 35°C = 12,8 litres per minute
Instantaneous DHW supply t 25°C = 17,9 litres per minute
DHW supply with Aqua Premiumfunction t 30°C = 200 l/10 min
DHW supply with Aqua Premiumfunction t 25°C = 240 l/10 min

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15 AST 14 C 152/00
3.4 TECHNICAL DATA
BTFS 24 BTFS 28 BTFS 32
Boiler category II2H3+ II2H3+ II2H3+
Burnernozzles No. 12 13 15
Minimum CH flow rate L/h 900 1000 1200
Minimum CH pressure Bar 0,5 0,5 0,5
Maximum CH pressure Bar 3 3 3
Minimum DHW pressure Bar 0,3 0,3 0,3
Maximum DHW pressure Bar 8 8 8
DHW specific flow rate (t 30 according to EN 625) L/ 10
min. 160 180 200
Electrical power supply –Voltage/Frequency V - HZ 230 - 50 230 - 50 230 - 50
Powermains fuse A 2 2 2
Maximum power consumption W 180 200 230
Net boiler weight Kg 67,0 67,5 68
Methane gas consumption (*) m3/h 2,70 3,23 3,46
Butane gas consumption kg/h 2,01 2,40 2,62
Propane gasconsumption kg/h 1,98 2,37 2,51
Maximum CH working temperature °C 83 83 83
Maximum DHW working temperature °C 62 62 62
Total capacity of expansion vessel L 8 10 10
Maximum recommended CH system capacity (**) L 160 200 200
(*) Value related to 15°C – 1013 mbar condition- (**) Maximumtemperature of water 83°C, expansion vessel pressure pre-charge 1 bar
BTFS 24 Max output Min output 30% output
Outer casing heat loss % 0,23 0,23 -
Flue system heat losswith burneron % 6,57 9,67 -
Flue gasmasscapacity g/sec. 14,0 14,4 -
Flue temp. – Air temp. °C 75 67 -
CO2 value % 7,2 2,8 -
Boiler efficiency rate % 93,2 90,1 90,2
BTFS 28 Max output Min output 30% output
Outer casing heat loss % 0,23 0,23 -
Flue system heat losswith burneron % 6,67 8,87 -
Flue gasmasscapacity g/sec. 18,2 18,7 -
Flue temp. – Air temp. °C 75 45 -
CO2 value % 6,6 2,1 -
Boiler efficiency rate % 93,1 90,9 90,4
BTFS 32 Max output Min output 30% output
Outer casing heat loss % 0,23 0,23 -
Flue system heat losswith burneron % 6,67 9,77 -
Flue gasmasscapacity g/sec. 18,9 19,2 -
Flue temp. – Air temp. °C 92 45 -
CO2 value % 6,9 2,5 -
Boiler efficiency rate % 93,1 90,0 90,3

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16 AST 14 C 152/00
CHP.4
GAS VALVE AND CONVERSIONS
4.1 GAS VALVE SIT 845
MAX/MIN RESISTANCE
VALUES OF THE COILS
EV1 – 880 Ohm at 220 Vac
EV2 – 6900 Ohm at 220 Vac
RESISTANCE VALUES OF THE
REGULATION COIL
78,2 Ohm
Gas inlet
pressure check
Gas outlet pressure
check
ELECTRICAL CONNECTIONS
OF MOTORIZED VALVES
GAS
OUT
To burner
GAS
IN
Mains supply
Maximum adjusting
screws
Minimum adjusting
screws

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17 AST 14 C 152/00
4.2 GAS CONVERSIONS
CONVERSION FROM NATURAL GAS TO LPG
Check that the boiler is disconnected from power mains;
Remove the main burner;
Remove the main burner nozzles and replace them with those bearing the correct
diameter in relation to the new gas type (see tables in chapter 3.3 “Operational data”) -
ATTENTION: it is mandatoryto install the copperseals;
Replace themain burner;
Replace the connection pipe between the gas valve and the manifold of the burner
nozzles;
Access the main electronic board and position the MET-LPG jumper to the LPG
position (see the photo below);
Now proceed with the adjustment of the gas valve (next page).
CONVERSION FROM LPG TO NATURAL GAS
Check that the boiler is disconnected from power mains;
Remove the main burner;
Remove the main burner nozzles and replace them with those bearing the correct
diameter in relation to the new gas type (see tables in chapter 3.3 “Operational data”) -
ATTENTION: it is mandatoryto install the copperseals;
Replace themain burner;
Replace the connection pipe between the gas valve and the manifold of the burner
nozzles;
Access the main electronic board and position the MET-LPG jumper to the MET
position (see the photo below);
Now proceed with the adjustment of the gas valve (next page).
Natural gas
Gas outlet pressure
check
LPG

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18 AST 14 C 152/00
4.3 GAS VALVE ADJUSTMENT
Remove the gas inlet pressure check screw by
means of a small screwdriver, and connect a
manometer in order to verify correct pressure
from the network;
connect a manometer to the gas outlet pressure
check after removing the screw of the gas outlet
check bymeans of a small screwdriver;
start the boiler in CH mode and to max output
(see paragraph 4.4 “Chimneysweep function);
remove the plastic protective cap A, act on
screw C clockwise to increase pressure and
counter-clockwise to decrease it (fully turn the
screw clockwise in LPG fuelled boilers);
after adjusting maxpressure, disconnect the blue coil wire in order to operate the boiler
at minimum output;
adjust minimum pressure by acting on the internal screw of the gas (while holding still
the external screw);
check correct operation of the burner verifying that the ignition is proper and quiet, act
on PACC trimmer of the electronic board when necessary in order to adjust ignition
power (clockwise to increase, anti-clockwise to decrease);
check for gas leaks;
seal once more the cap screw;
once the above procedure is complete, fill in the tag enclosed with the kit and affix it to
the side of the technical data label of the boiler.
4.4 “CHIMNEYSWEEP” FUNCTION
The boiler has a “chimneysweep” function in order to
test boiler combustion efficiency and to adjust the
burner.
Set the boiler selector knob to WINTER mode and
the room thermostat to ON (if available). While the
boiler is operating, press the SPA button with a
pointed tool (A in the picture below); the boiler will
turn OFF and then resume ignition sequence and
proceed operating with a maximum output.
The “Chimneysweep” function running time is 15 minutes.
In order to deactivate the “chimney sweep” function, turn the selector to any position other
than WINTER.

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19 AST 14 C 152/00
CHP.5
HYDRAULIC GROUP
5.1COMPLETE HYDRAULIC GROUP
THE HYDRAULIC GROUP OF NIAS-LIBRA DUAL BOILER WAS DESIGNED COMPLETLEY BY
FONDITAL ENGINEERS AS WITH ALL OF THE OTHER HYDRAULIC GROUPS OF OUR BOILERS.
DHW and CH probe parameters: 10Kohm at 25°C with =3435
Pump
CH probe
DHW probe
Thre
e
-
way
valve motor
DHW plate heat
exchanger
3 bar safety
valve
Flowpressure
gauge
Three
-
way
valve Loading tap
Flowmeter

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20 AST 14 C 152/00
5.2 SECONDARY PLATE HEAT EXCHANGER
ALFALAVAL
24 kW 22 plates
28 kW 26 plates
32 kW 26 plates
5.3 THREE-WAY VALVE
5.4 2-WAY INTERCEPTION VALVE
- Maximum working
temperature: 88°C
- Maximum working
pressure: 3 Bar
- 230V/ 3W T60
Adjustable by-pass
Electric motor
Shutter
By-pass adjusting screw
OPEN BY-PASS
CLOSED BY-PASS