Ferroli Domina Plus F 24-30 E, Ferella Extra F 24-30 MEL Technical Manual

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

Wall-Mounting Gas
Boiler with antifreeze
for tap water



Airtight Chamber, for
Hot Water and Heating

TECHNICAL

DOMINA PLUS F 24-30 E

FERELLA EXTRA F 24-30 MEL

MANUAL

EDITION

092002

Supplied By www.heating spares.co Tel. [phone]

DOMINA PLUS F 24 - 30 E

FERELLA EXTRA F 24 - 30 MEL

1. Technical characteristics and data ........................................................ 3

1.1 Introduction .............................................................................................................. 3

1.2 Dimensions and connections .................................................................................. 4

1.3 General view and main components ....................................................................... 8

1.4 Technical data table ............................................................................................... 10

2. Hydraulic circuit - heating ................................................................... 11

2.1 Hydraulic circuit - heating ...................................................................................... 11

2.2 Hydraulic circuit - tap water ................................................................................... 15

2.3 Gas circuit .............................................................................................................17

2.4 Burner unit ............................................................................................................. 21

2.5 Fume circuit .......................................................................................................... 23

2.6 Electrical circuit ..................................................................................................... 27

3. Operation ............................................................................................ 30

3.1 Operating principle ................................................................................................ 30

3.2 Operating diagram................................................................................................. 32

3.3 Control panel ......................................................................................................... 33

3.4 Adjustments ........................................................................................................... 35

3.5 Operating parameter adjustment .......................................................................... 38

4. Unit self-diagnosis .............................................................................. 43

2

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DOMINA PLUS F 24 - 30 E

FERELLA EXTRA F 24 - 30 MEL

1. TECHNICAL CHARACTERISTICS AND DATA

1.1 Introduction

Our unit is a high-efficiency heat generator for heating and hot water production running on natural or liquefied
petroleum gas (configurable at the time of installation) and regulated by an advanced microprocessor control
system.

The boiler shell consists of a copper laminar exchanger whose particular shape guarantees high exchange
efficiency under all operating conditions and an open-flue burner equipped with electronic ignition and ionization
flame control.

The boiler is totally sealed off from the installation room: the air needed for combustion is drawn from outside
and the flue gases are expelled by a fan. The boiler outfit moreover includes a variable speed circulator,
expansion tank, flow meter, safety valve, filler cock, air pressure switch, water pressure switch, temperature
sensors, safety thermostat and an antifreeze thermostat with the relevant heating elements.

Thanks to the microprocessor control and adjustment system with advanced self-diagnosis, unit operation is
for the most part automatic. The power for heating is automatically governed by the control system according
to the indoor and outdoor characteristics (with an optional outdoor sensor installed), the characteristics of the
building and of its location. The power for hot water is automatically and continually governed to ensure a fast
delivery and comfort under all operating conditions.

The display continuously provides information on the unit's operating status and it is easily possible to obtain
additional information on the sensor temperatures, set-points, etc. or configure them. Any operating trouble
associated with the boiler or system is immediately signalled by the display and, if possible, corrected
automatically.

General Warnings

· Installation and maintenance must be carried out by professionally qualified personnel, according
to current regulations and the manufacturer's instructions.

· Incorrect installation or poor maintenance can cause damage or physical injury. The manufacturer
declines any responsibility for damage caused by errors in installation and use or by failure to
follow the manufacturer's instructions given in the instructions manual.

· Before carrying out any cleaning or maintenance operation, disconnect the unit from the electrical
power supply using the switch and/or the special cut-off devices.

Certification

The CE marking demonstrates that Ferroli gas units conform to the requirements contained in the
applicable European directives.
In particular, this unit complies with the following EU directives:

· Gas Appliance Directive 90/396 assimilated with Italian Presidential Decree DPR 15.11.96 no. 661

· Efficiency Directive 92/42 assimilated with Italian Presidential Decree DPR 15.11.96 no. 660

· Low Voltage Directive 73/23 (amended by 93/68)

· Electromagnetic Compatibility Directive 89/336 (amended by 93/68) assimilated with Italian

Presidential Decree DPR 15.11.96 no. 615

Version - 09.2002

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DOMINA PLUS F 24 - 30 E

FERELLA EXTRA F 24 - 30 MEL

1.2 Dimensions and connections

Domina Plus F 24 E version

Top view

460

15012012070

110

10

725

Connections axis

Connections axis

100

270

720

80 80

80

175100

460

16025

Key

1 System delivery
2 Tap water outlet
3 Gas inlet
4 Tap water inlet
5 System return

4

100

1

2

Bottom view

1149560609536

4

3

5

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DOMINA PLUS F 24 - 30 E

FERELLA EXTRA F 24 - 30 MEL

Ferella Extra F 24 MEL version

110

Top view

460

15012012070

10

725

Connections axis

Connections axis

100

270

720

80 80

80

175100

460

16025

Key

1 System delivery
2 Tap water outlet
3 Gas inlet
4 Tap water inlet
5 System return

Version - 09.2002

100

1

2

Bottom view

1149560609536

4

3

5

5

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DOMINA PLUS F 24 - 30 E

FERELLA EXTRA F 24 - 30 MEL

Domina Plus F 30 E version

200

Top view

460

120120110

110

14

733

Connections axis

420

80

8080

430362

189

1

Key

1 System delivery
2 Tap water outlet
3 Gas inlet
4 Tap water inlet
5 System return

189

36 95 60 60 155 54

6

460

23

4

Bottom view

5

175

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DOMINA PLUS F 24 - 30 E

FERELLA EXTRA F 24 - 30 MEL

Ferella Extra F 30 MEL version

200

Top view

460

120120110

110

14

733

362

Connections axis

720

80

8080

430

189

Key

1 System delivery
2 Tap water outlet
3 Gas inlet
4 Tap water inlet
5 System return

Version - 09.2002

460

1

23

189

36 95 60 60 155 54

4

Bottom view

5

175

7

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DOMINA PLUS F 24 - 30 E

FERELLA EXTRA F 24 - 30 MEL

1.3 General view and main components

F 24 E/MEL version

29 43

187

5

28

90

132

49

34

81

8222

20
21

R4

3

4

2

1

5

0

6

114

OUT

R3

IN

MIN

R2

10 874 784 85 44

14 42 9 11

RESET

°C °C

R1

136

56

16

91

27

19

26

36
73

32

Key

5 Airtight chamber
7 Gas inlet
8 Tap water outlet

9 Tap water inlet
10 System delivery
11 System return
14 Safety valve
16 Fan
19 Combustion chamber
20 Burner assembly
21 Main nozzle
22 Burner
26 Combustion chamber insulation
27 Copper exchanger for heating and

tap water
28 Fume manifold
29 Fume outlet manifold
32 Heating circulator
34 Heating temp. sensor
36 Automatic air vent
42 Tap water temperature sensor
43 Air pressure switch
44 Gas valve
49 Safety thermostat
56 Expansion tank
63 Heating temperature setting
73 Antifreeze thermostat
74 System filler cock
81 Ignition electrode
82 Detection electrode
84 1st gas valve operator
85 2nd gas valve operator
90 Fume detection point
91 Air detection point
98 Off-On-Reset switch

114 Water pressure switch
132 Fume deflector
136 Flow meter
145 Water gauge
157 Tap water temperature setting
187 Fume diaphragm
R1-R2-R3-R4 Antifreeze heating elements

98 63 157

145

8

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DOMINA PLUS F 24 - 30 E

FERELLA EXTRA F 24 - 30 MEL

F 30 E/MEL version

28

90

132

49

34

56

20
21

73

114

29 43187

Key

5 Airtight chamber
7 Gas inlet
8 Tap water outlet

5

16

91

27

9 Tap water inlet
10 System delivery
11 System return
14 Safety valve
16 Fan
19 Combustion chamber
20 Burner assembly
21 Main nozzle
22 Burner
26 Combustion chamber insulation
27 Copper exchanger for heating and

tap water

28 Fume manifold

19

818222

26

29 Fume outlet manifold
32 Heating circulator
34 Heating temp. sensor
36 Automatic air vent
42 Tap water temperature sensor
43 Air pressure switch
44 Gas valve
49 Safety thermostat
56 Expansion tank

36

63 Heating temperature setting
73 Antifreeze thermostat
74 System filler cock
81 Ignition electrode

R3

OUT

IN

MIN

R4

GRUNDFOS

32

82 Detection electrode
84 1st gas valve operator
85 2nd gas valve operator
90 Fume detection point
91 Air detection point
98 Off-On-Reset switch

R2

R1

114 Water pressure switch
132 Fume deflector

10 8 784 85 44

74

14 42 9 11

136

136 Flow meter
145 Water gauge
157 Tap water temperature setting
187 Fume diaphragm

RESET

°C °C

3

4

2

1

5

0

6

R1-R2-R3-R4 Antifreeze heating elements

98 63 157

145

Version - 09.2002

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FERELLA EXTRA F 24 - 30 MEL

1.4 Technical data table

DOMINA PLUS F 24 - 30 E

DOMINA PLUS - FERELLA EXTRA

Powers Pmax Pmin

Heating Power (Net Heat Value - Hi)

Useful Heating Power 80°C - 60°C

Tap Water Heating Power

Gas supply Pmax Pmin

Natural Gas main nozzles (G20) mm 12 x 1.30
Natural Gas supply pressure (G20) mbar 20.0
Pressure at Natural Gas burner (G20) mbar 11.8 2.5
Natural Gas delivery (G20) nm
LPG main nozzles (G31) mm 12 x 0.77
LPG supply pressure (G31) mbar 37.0
Pressure at LPG burner (G31) mbar 36.0 7.8
LPG delivery (G31) kg/h 2.00 0.89

Heating

Maximum working temperature in heating °C 90
Maximum working pressure in heating bar 3
Safety valve bar 3
Minimum working pressure in heating bar 0.8
Expansion tank capacity litres 7
Expansion tank pre-filling pressure bar 1
Boiler water content litres 0.8

Tap water

Maximum hot water production Dt 25°C l/min 13.6
Maximum hot water production Dt 30°C l/min 11.3
Maximum working pressure in hot water production bar 9
Minimum working pressure in hot water production bar 0.25
Hot water content litres 0.8

Dimensions, weights connections

Height mm 760
Width mm 460
Depth mm 272
Weight kg 38
Gas system connection inches 1/2
Heating system connections inches 3/4
Hot water circuit connections inches 1/2

Electrical power supply

Max electrical power absorbed W 125
Power voltage/frequency V/Hz 230/50
Electrical protection rating IP 44

kW 25.8 11.5

kcal/h 22,200 9,900

kW 23.8 9.7

kcal/h 20,400 8,300

kW 23.8 9.7

kcal/h 20,400 8,300

3

/h 2.73 1.22

24kW 30kW

Pmax Pmin

33.1 14.5

28,500 12,500

30.0 12.7

25,800 10,900

30.0 12.7

25,800 10,900

Pmax Pmin

16 x 1.25

20.0

13.0 2.5

3.50 1.53
16 x 0.75

37.0

35.5 7.0

2.60 1.14

90

3
3

0.8
10

1

1.5

17.2

14.3
9

0.25

0.8

760
460
363

48
1/2
3/4
1/2

125

230/50

44

10

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DOMINA PLUS F 24 - 30 E

FERELLA EXTRA F 24 - 30 MEL

2. PRODUCT FRAMEWORK AND INTERNAL
COMPONENTS

2.1 Hydraulic circuit - heating

Hydraulic diagram for heating

When there is a call for heat, the room thermostat or control system make the burners ignite and the circulation
pump come into operation. The heat contained in the products of combustion is transferred to the water by the
system via the exchanger. For more details on the operating logic, refer to chap.3.

Key

29-187

16

49

34

27

82

20

73

5 Airtight chamber

-

+

5

R1

R2

43

7 Gas inlet
8 Tap water outlet

9 Tap water inlet
10 System delivery
11 System return
14 Safety valve
16 Fan
20 Burner assembly
27 Heat exchanger
29 Fume outlet collar
32 Heating circulator

56

34 Heating temperature sensor
42 Tap water temperature sensor
43 Air pressure switch
44 Gas valve

81

49 Safety thermostat
56 Expansion tank
73 Antifreeze thermostat
74 System filler cock
81 Ignition electrode
82 Detection electrode

114 Water pressure switch
136 Flow meter

44

187 Fume diaphragm
R1-R2-R3-R4 Antifreeze heating elements

42

114

14

74

Version - 09.2002

R3

8

7

R4

1110

9

32

136

11

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DOMINA PLUS F 24 - 30 E

FERELLA EXTRA F 24 - 30 MEL

Circulator (230v/50Hz)

Located on the heating circuit return, it is connected directly to the exchanger
via special forks and connected to the system via a threaded brass section. It has
three delivery/head levels (see diagram). Changing the delivery/head changes
the speed of the water flowing through the boiler exchanger and as a result the
temperature difference (DT) between heating delivery and return. Clearly,
increasing the delivery of the circulator decreases DT and vice versa. If it is not
used for a long time, the impeller might "jam" due to debris in the water. With the
front screw it is possible to access the impeller, which can be freed with the aid
of a screwdriver. The connection to the expansion tank and the air separator is
installed on the pump casing.

Checks

If the pump doesn't work:

· Check that the impeller is free to turn by turning the screw on the front with a
screwdriver.

· Check that both the card and the pump connection are powered.

· If there is no power supply, check the card.

· If there is power, change the pump.

Key

1 - 2 - 3 = Pump selector position

mC.A.

6

5.5

5

4.5

4

3.5

3

2.5

2

1.5

1

0.5

0

0 0.25 0.75 1.25 1.75 2.25 2.752.51.50.5 1 2 3

1

3

2

A

B

Air separator

This is used to expel the air in the heating circuit automatically. On boilers with
a twin heat exchanger, it is located on the pump casing. It is normally accessible
either via the fork or by simply unscrewing it from its seat.

A = Losses of head 24kW version
B = Losses of head 30kW version

3.2 3.4 3.6 3.8 4

3

m

/ h

12

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FERELLA EXTRA F 24 - 30 MEL

Expansion tank

It is connected to the pump casing via a pipe with a fork connection. On the 24kW version, it is located above
the pump, while on the 30kW version it is located behind the exchanger, inside the frame. The expansion tank
contains a diaphragm in contact, on one side, with the system water and, on the other side, with the air under
pressure (pre-loaded to 1 bar) inside the tank. By the expansion of the diaphragm and ensuing compression
of the air, the tank compensates for the thermal expansion of the water in the heating system.

Version 24kW

7 litre

Version 30kW

10 litre

Twin Heat Exchanger

The exchanger is a copper laminar assembly. It comprises a thickly finned portion, three circular pipes
containing the heating water and, inside them, another three pipes in the form of a spiral containing the tap water.
The heating water exchanges directly with the burnt gases, while the tap water does not have this kind of
exchange, it receives heat indirectly from the water in the three heating pipes. In this way, the surface of the
coil does not reach very high temperatures so less scale gets formed. In addition, being very small, it makes
the water speed very high over its entire section, making mineral deposits of any kind negligible. The typical
"omega" shape of the finning ensures an even distribution of the heat over all the finning, with consequent
benefits in terms of exchange efficiency and the life of the exchanger. A special surface treatment protects the
exchanger against oxidation and corrosion.

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Hydraulic unit

This is a single piece of brass to which the exchanger
delivery is connected for ease of access. It
accommodates a number of safety and adjustment
components.

The hydraulic unit includes:

- safety valve

- water pressure switch

- heating sensor

- filler cock

- tap water sensor

- tap water check valve

Water pressure switch

It ensures a minimum pressure for the system. It is normally open (NO) and
closes the contact when the pressure exceeds 0.5 bar. It works on low voltage.

Safety valve

It opens if the pressure exceeds 3 bars, making boiler operation safer and
protecting it against overpressure. You are strongly recommended not to use this
valve to drain the system; once open, dirt could remain inside it, preventing it from
closing completely.

Check valve

This is necessary to ensure no water returns from the heating system to the tap
water circuit.

Filler cock

This is located between the heating delivery and the tap water outlet. It is not fitted
on the boiler for some markets such as the British and Belgian ones.

14

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2.2 Hydraulic circuit - tap water

Hydraulic diagram for tap water

29-187

16

49

34

27

82

20

73

42

34

114

14

74

-

+

5

R1

R3

8

7

R4

9

R2

1110

43

Key

56

5 Airtight chamber
7 Gas inlet
8 Tap water outlet
9 Tap water inlet

81

10 System delivery
11 System return
14 Safety valve
16 Fan
20 Burner assembly
27 Heat exchanger
29 Fume outlet collar
32 Heating circulator

44

34 Heating temperature sensor
42 Tap water temperature sensor
43 Air pressure switch
44 Gas valve
49 Safety thermostat
56 Expansion tank

32

73 Antifreeze thermostat
74 System filler cock

136

81 Ignition electrode

82 Detection electrode
114 Water pressure switch
136 Flow meter
187 Fume diaphragm
R1-R2-R3-R4 Antifreeze heating elements

When the card receives a signal from the flow meter indicating a tap-water draw of over 2.5 l/min, the boiler starts
working normally for tap water. If heating was in operation, or the pump was anyhow working, the boiler will in
any case give priority to the tap water, stopping the pump. The tap water does not exchange directly with the
products of combustion, but via the heating water in the exchanger, avoiding sudden changes in temperature.
The boiler is equipped with 4 heating elements and an antifreeze thermostat in order to protect the tap water
pipes if the temperature drops under 6°C. The heating elements heat the pipes up to a temperature of 15°C
measured by the thermostat.

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Flow meter

Located at the cold water inlet, its task is to provide the card with a signal at a
frequency (7 Hz per litre) in direct proportion to the tap-water flow rate. It is
composed of a body (stator) and a rotor inside it. There is a filter on its inlet to
prevent foreign bodies damaging it. It should be remembered that to turn on the
boiler for tap-water operation, the tap-water pressure must be at least 0.25 bars
and the draw flow rate must be greater than 2.5 l/min.

Check

To check it works properly, you need to make sure the flow rate is at least

2.5 l/min and then test the signal to the electric card with a frequency meter. This
makes it possible to understand whether the problem lies with the flow meter,
incorrect contacts, or the card.

Flow-rate restrictor

This is a diaphragm downstream from the flow meter. Its task is to limit the tap­water flow rate; the boiler modulates its capacity to keep the tap-water
temperature set by the user, but since the boiler capacity is limited to its rated
capacity, it is necessary to limit the tap-water flow rate to obtain high

24 kW version
30kW version

65

60

55

*

m

50

T.

31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10

kcal/h

x1000

45

Tap water delivery temperature °C

40
39

Tap water inlet temp. 15°C

0 345678910111213141516

Tap-water flow rate dm /min

3

16

In this case, above the flow­rate limit m, even though the

*

boiler is working at its rated
capacity, it is not able to

Exchanged boiler capacity

17

18

maintain the set temperature
of 50°C

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2.3 Gas circuit

Gas circuit diagram

DOMINA PLUS F 24 - 30 E

29-187

16

49

34

27

82

20

73

42

34

114

14

74

-

+

5

R1

R3

8

7

R4

9

R2

1110

43

Key

56

5 Airtight chamber
7 Gas inlet
8 Tap water outlet
9 Tap water inlet

81

10 System delivery
11 System return
14 Safety valve
16 Fan
20 Burner assembly
27 Heat exchanger
29 Fume outlet collar
32 Heating circulator

44

34 Heating temperature sensor
42 Tap water temperature sensor
43 Air pressure switch
44 Gas valve
49 Safety thermostat
56 Expansion tank

32

73 Antifreeze thermostat

136

74 System filler cock
81 Ignition electrode

82 Detection electrode
114 Water pressure switch
136 Flow meter
187 Fume diaphragm
R1-R2-R3-R4 Antifreeze heating elements

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Gas valve

It supplies gas to the nozzles between a minimum and maximum pressure. For
the valve to work correctly, it is necessary for the pressure upstream from it to
be stable and suited to the type of gas being used, while the valve will supply a
regular pressure to the nozzles. The gas valve contains two operators. The
function of the first one is to open or close, while the task of the second one is
to modulate the capacity according to the system's requirements. The signal
comes from the card and is in the form of continuous voltage. The first operator
receives fixed voltage that may be between 80 and 110V DC, for the second
operator the voltage will vary between 25 and 54V DC according to the need of
the main card.

Checks

If the valve doesn't work:

· The only possible check is to see whether gas comes out of the screw "B" at
the rated pressure when setting the boiler on "test" with the boiler at full power
(see "Test Functions" chap. 3.1).

B

IN OUT

25±50V DC

COMMON

80±110V DC

Modulation

The control system governs its boiler capacity so as to keep the delivery temperature constant in accordance
with the settings on the control panel. The nozzle gas pressure is modulated by the valve and specifically via
the 2nd operator. The card provides a change in continuous voltage (between 25 and 54 V DC ) according to the
difference between the delivery temperature and the set point.

Checks

Modulation can be checked in three ways:

· Visually, by checking the flame.

· Using a pressure gauge to check the gas pressure downstream from the valve.

· Checking the voltage on the card (X6, 3/4) that should vary between 25 and 55V

Note that with very low pressure upstream from the valve, opening the valve may be slow and the boiler
could shut down due to failed ignition.

DC.

18

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DOMINA PLUS F 24 - 30 E

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Adjusting burner pressure

Since this unit has flame modulation, there are two fixed pressure settings: the minimum and maximum, which
must be as stated in the technical data chart according to the type of gas.

· Connect a suitable pressure gauge to pressure point "B"
downstream from the gas valve.

· Disconnect the pressure compensation tube "F" .

· Take off the protective cap "C".

· Run the boiler in TEST mode (pressing RESET 3 times

consecutively within 5 sec.).

· Set knob 2 on minimum.

· Adjust the minimum pressure with the screw "D", clockwise to

decrease it and anticlockwise to increase it.

· Set knob 2 on maximum (clockwise).

· Adjust the maximum pressure with the screw "E", clockwise to

increase it and anticlockwise to decrease it.

· Reconnect the pressure compensation tube "F".

· Put the protection screw "C" back in.

F

C

N.B. The test lasts 5 minutes. It is advisable to open 1 or 2 taps to

get rid of the excess capacity.

After checking or

adjusting the pressure,
it is mandatory to seal the
adjustment screw with paint or
a specific seal.

35

30

24 kW version
30kW version

mbar

25

20

G31
LPG

E

B

IN OUT

A

D

25±50V DC

COMMON

80±110V DC

Key

A Pressure point upstream
B Pressure point downstream
C Protection screw
D Minimum pressure adjustment screw
E Maximum pressure adjustment screw
F Pressure compensation tube

15

10

5

kW

9101112 13 14 15 16 17

8

18 19 20 21 22 23

Version - 09.2002

G20
Nat. Gas

24 25 26 27 28 29 30 31 32 33 34

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Gas supply conversion

The unit can function with either Natural Gas or LPG and is factory-set for use with one of the two gases, as
clearly shown on the packing and on the unit's dataplate. Whenever a different gas to that for which the unit
is preset has to be used, a conversion kit will be required, proceeding as follows:

1 Replace the nozzles at the main burner, inserting

the nozzles specified in the technical data
table, according to the type of gas used.

2 Using the remote control, edit parameter 3 of

the boiler parameter menu.

3 Adjust the burner minimum and maximum

pressures, setting the values given in the
technical data chart for the type of gas used.

4 Apply the sticker, contained in the conversion

kit, near the dataplate as proof of the conversion.

20

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2.4 Burner unit

Operation

The burner unit comprises a manifold and 12/16 nozzles (depending on the capacity), the burner mount,
electrodes and the burner assembly.

Manifold - nozzles

The valve sends gas at a suitable pressure to the manifold, which homogeneously
distributes the gas to the single burner stages at the nozzles. It is secured
directly to the burner mount. Its positioning must be exact since it affects the air/
gas mixture. In addition, the threaded holes forming the seat of the nozzles must
be aligned with the respective Venturi tube of the burner. If it were not so, the air/
gas mixture would be wrong and there would be poor combustion with an unstable
flame. The nozzles are made of brass and machined extremely precisely for their
dimensions. There is a seal between the nozzles and the manifold.

Ignition electrode

The ignition electrode is made of a metal alloy (Kanthal) that withstands high
temperatures and oxidation. Its base is composed of a ceramic composite of
glazed alumina whose purpose is to protect and electrically insulate it. Once the
ignition procedure begins, the card powers the electrode with a pulsating voltage
of a few kV, a series of electrical discharges is set off between the electrode and
the head of the burner (set at a distance of 3.5 mm). Clearly, these sparks are
the trigger for the air-gas mixture. It is important for the distance between the
electrode and the burner head to be 3¸ 4 mm and the discharge to be made at
the centre.

Checks

If there is no discharge:

· Check whether the boiler shuts down, in which case check the
connection of the electrode to the card or whether it discharges at
other points; if necessary, check the safety thermostat and the card.

· If the boiler does not shut down and the fan keeps on working,
check the air pressure switch.

· If there is a discharge, but no ignition and after 10 seconds the
boiler shuts down, check the gas valve and, if necessary, the
card.

· If there is a discharge and then a flame, but the boiler still shuts
down after 10 seconds, check the detection electrode and its
connection.

±0.5

3.5

Version - 09.2002

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Detection electrode

Made of the same material as the ignition electrode, it is set 11 mm from the
burner head. Combustion causes the flame atmosphere to ionize, making it
conductive. Thanks to the mass of the burner, making a suitable potential with
the electrode produces a flow of direct current on it. For our cards, it is
necessary to have an ionizing current of at least 5 µA to detect a flame. A
signal is normally obtained ranging from 10 to 40µA (see chap. 3.1).

Burner assembly

The burner assembly is composed of 12 or 16 burner stages. Each stage is composed of two pressed steel
half bearings, with a suitably cut stainless steel head. Gas enters at the bottom of the stage. Thanks to the
special Venturi-tube shape of the bottom portion of the stage, the gas "injected" by the nozzle carries with it
the primary air needed for combustion. The air-gas mixture thus formed inside the stage is evenly distributed
on the burner head. Combustion takes place homogeneously over the entire length of the single stages, with
the contribution of the secondary air from the bottom of the burner mount and from the combustion chamber
itself. The set of stages in operation forms a single belt of flame, light blue in colour, whose size varies according
to the nozzle gas pressure, that is the boiler capacity modulation.

22

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2.5 Fume circuit

Fume deflector and manifold

All forced-flow boilers have a fume deflector above the exchanger whose main
task is to make the secondary air crossing the burners uniform, making the flame
homogeneous and stable. The fumes then reach a fume manifold whose job is
to make them move on to the fan.

Airtight chamber

Its task is to isolate the products of combustion from the area surrounding the
boiler. The airtight chamber contains all the components involved in the fume
routing. The wires and pipes coming out of its lower portion are insulated with
silicone seals, while its upper portion is fitted for hooking up with the flues. The
cover is sealed off with a porous plate and is fitted with two plugs for using a probe
to analyse the fumes and combustion air.

Fan and pressure switch points

Powered at 230V/50Hz by the card (X11 - 1/2), the fan has
the job of expelling the products of combustion from the fume
chamber. A plate is normally placed above the exchanger to
act as a deflector, make the incoming air from the bottom of
the burner uniform, make the flame stable and obtain the
required air/gas ratio. In order to make sure the fan works
properly, there are two pressure points inside it. The first one
detects a "static" pressure signal that is positive, the second
one detects a "dynamic" pressure signal via an appropriate
"Venturi tube", which is negative. With the difference in
pressure detected by the two test points it is possible to
check whether the fumes are adequately evacuated.

Version - 09.2002

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Air pressure switch

This is used to check whether the fumes are adequately evacuated. The pressure switch compares the static
and dynamic signals coming from the pressure test points on the fan according to the figure. The pressure switch
is connected to the card and is normally open (see diagram). Before the card initiates the ignition procedure
(opening the valve, etc.), you must make sure that the fan works properly and that the air pressure switch
ensures this by closing its contacts. This happens if the difference in pressure is 165±15Pa. So the signal must
be at least 180Pa. To open its contacts again, the difference in pressure must drop under 150±13Pa. To perform
checks on contact opening and closing, it is always recommended to check directly on the card (X5 - 3/4).

Checks

It is necessary to check:

· Whether the electrical connections are correct.

· Whether the pressure test point pipes are clean and contain no condensation water.

· That the signal is open when the fan is not working.

· That the pressure is at least 180Pa and that above this pressure the pressure switch closes its contacts.

· If the signal is low, it is necessary to check that the fume diaphragm is correct, the fan has 230V, the pressure

test points are properly inserted and the Venturi tube has no burrs of any kind. Lastly, check that the ends
of the pipes are not obstructed.

N.B. The pressure difference must be measured with the airtight chamber closed. The pressure gauge

connections can come out through the hole, which is closed by a silicone plug, on the front of the cover.

C

NC

NO

Key

NO = Normally open
NC = Closed
C=Common

Pressure

gauge

pa

24

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Pipe length
calculated in
linear metres

Diaphragm

to use

45 mm

47 mm

50 mm

No diaph.

Min

0 m

13 m

23 m

38 m

Max

13 m

23 m

38 m

48 m

F 24

F 30

47 mm

50 mm

52 mm

No diaph.

Diaphragm

to use

Min

0 m

20 m

35 m

45 m

Max

20 m

35 m

45 m

50 m

Pipe length
calculated in
linear metres

FERELLA EXTRA F 24 - 30 MEL

Fume ducts

The unit is "type C" with an airtight chamber and forced draught, the air inlet and fume outlet must be connected
to one of the following extraction/suction systems. With the aid of the tables and methods of calculation
indicated, before commencing installation, it is first necessary to check that the fume ducts do not exceed the
maximum permissible lengths. The current standards and local regulations must be observed.

This C-type unit must be installed using the fume exhaust and suction ducts supplied by FERROLI
S.p.A. in accordance with UNI-CIG 7129/92. Failure to use them automatically forfeits all warranty and
liability of FERROLI S.p.A.

Diaphragms

Boiler operation requires fitting the diaphragms supplied with the unit as instructed in the following tables. As
the resistance of the fume ducts changes, the diaphragms make it possible to keep the combustion parameters
(CO2, etc.) within the optimum operating range. Note that with low-resistance fume ducts, a high-resistance
diaphragm (small hole diameter) is used and vice versa.

Choosing the diaphragm using coaxial
pipes

Diaphragm

Type

Coaxial

60/100

Coaxial

80/125

Length up to:

1 bend + 1 metre

1 bend + 3 metres

1 bend + 3 metres

1 bend + 4 metres

1 bend + 5 metres

to use

F 24

50 mm

No diaph.

45 mm

50 mm

No diaph.

F 30

52 mm

No diaph.

50 mm

No diaph.

No diaph.

Changing the diaphragm

If inserting or changing a diaphragm, it is necessary to
remove the fan assembly, take out the fume coupling 1 and
insert the required diaphragm 2.

N.B.:
The diameter
of the hole Ø
is stamped
on the
diaphragm

Ø

Choosing the diaphragm using
separate pipes

.

1

Boilers are fitted as
standard with the
smallest diaphragm in
the series.
Before inserting the fume outlet pipe, it is therefore
necessary to check there is the right diaphragm

Version - 09.2002

(when it is to be used) and that it is correctly
positioned.

.

2

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Calculation example

Here we give an example of the calculation for a separate fume
outlet. We recommend inserting a condensate trap on long
vertical sections to prevent condensation getting onto the
burner and damaging it. If monitoring the condensate trap is
not guaranteed, it must be fitted with a suitable drain pipe and
air trap, which in its turn must be appropriately connected to
a suitable drain.

6

Ref.

1

2

3

4

5

6

No. Pieces

1

1

1

1

36

1

Description

Air bend Ø80

Horizontal air pipe Ø80

Windproof end piece

Condensate collection cup coupling

Vertical fume pipe Ø80

Outlet flue + coupling

Total

5

4

1 2 3

Equivalent

loss

1.5 m

1.0 m

2.0 m

3.0 m

36.0 m

4,0 m

47.5 m

26

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2.6 Electrical circuit

Electrical terminal board

Follow the instructions given in the figure to access the electrical connection terminal board.

The layout of the terminals for the various connections is given in the wiring diagram.

81 82

Wiring diagram

Key

16 Fan
32 Heating circulator
34 Heating temperature sensor
42 Tap water temperature sensor
43 Air pressure switch
49 Safety thermostat
72 Room thermostat (not supplied)
73 Antifreeze thermostat

N.B. Respect the phase and neutral connections

R4

2314

MV3

MV4

R1 R2 R3

73

X1

X2

44

MV1

MV2

X6

X8

16

32

X3

X11

12

81 Ignition electrode

82 Detection electrode
114 Water pressure switch
136 Flow meter
138 External sensor (not supplied)
139 Remote control (not supplied)

X9

X12

1223811212

X5

230V ~
50Hz

NL

72

139

138

N

L

12 11 10 9 8 7 6 5 4 3 2 1

34

43

42 114

49

1234567

136

-+

X4

12345678910111213

MF05FD

X7

Version - 09.2002

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Main electronic card

The electronic card is a Honeywell DMF05FD: part of the card works on low
voltage (24V) and the remainder on 230V (see diagram). It is fitted with a fuse
(2A). There are loads and controls common to the card that have already been
described, such as:

· Pump

· Fan

· Gas valve

· Air pressure switch

There remain some components described hereunder.

Ignition + detection electrode, see chap. 2.4 Burner Unit

28

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Safety thermostat

X5 - 1/2 has a thermostat with gold contacts that opens if the temperature
exceeds 100°C. Connected directly to the main card, when it opens it cuts off
the power supply to the valve directly, shutting down the boiler. It is set on the
left-hand side of the exchanger by a spring.

Heating and tap water temperature probe

These are NTC sensors that increase their resistance as the temperature
decreases and are connected directly to the main card X4 - 24V (heating 12-13,
tap water 10-11). The heating sensor performs the antifreeze function too.

Temperature ( C° )

100

90

80

70

60

50

40

30

25

15

5

Resistance ( k Ohm )

0,68

0,92

1,25

1,7

2,5

3,6

5,3

8

10

15,6

25,3

NTC sensor

33

30

27

24

21

18

15

12

Resistance ( k Ohm )

9

6

3

0

0 20 40 60 80 100 120

Temperature ( C° )

Version - 09.2002

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3. OPERATION

3.1 Operating principle.

The boiler is designed to function with two types of gas: Natural Gas or LPG. It works with systems on the
cutting edge of technology as it uses sophisticated software with a double processor governing the
modulation, power, control and safety equipment. On powering up the boiler from the mains for the first time,
the display will show in succession: 88.-LO-14-HI-06-EO-14 that represent the software release of the
processor for low (LO) and high (HI) voltage and the memories (EO). Lastly, the boiler will go onto stand-by,
with LED 5 on and the delivery temperature on the display.

When there is a call for heating, the circulator and fan start working; then the air pressure switch enables the
control and safety unit to ignite the burner. Via the electronic flame modulation system, the boiler capacity
is gradually metered till it reaches the set delivery temperature. If the power needed for the heating plant is
lower than the minimum boiler power, when the delivery temperature exceeds the setting of 6°C, the burner
switches off and the electronic system enables re-ignition only after another 2 minutes. On reaching the set
ambient temperature (room thermostat), the burner switches off and the circulator keeps on working for
another 6 minutes to enable better heat distribution throughout the system. If the remote control (Ferroli) is
used, the system will try to modulate the ambient temperature according to the setting. In this passage the
remote control can lower the delivery temperature under the setting to maintain the ambient temperature: in
any case, if the ambient temperature exceeds the remote control setting by 1°C the burner switches off and
the circulator stays on for post-circulation.

If hot tap water is drawn off during the heating phase, the electrical heating circuit automatically turns off and
the hot tap water production circuit switches on.

Throughout this phase the heating system circulator stops and the boiler delivers water at the set temperature.

The boiler keeps the tap water temperature constant by means of flame modulation, even when different
quantities are drawn off.

Diagnosis characteristics: the boiler shows the type of trouble directly on the display with an identification
code.

Slow ignition for heating

The power in the ignition phase (10s) is 50% (adjustable) and the increase in temperature is gradual
(10°C/minute - adjustable from 1 to 20°C).

Circulator anti-locking

If not used for 24 h, the heating circulator is turned on for a few seconds to prevent it locking due to an extended
stoppage.

Antifreeze protection

With the heating temperature sensor, if the temperature falls under 5°C, the boiler starts working normally
to then switch off when the temperature exceeds 15°C, and the circulator keeps on working for another
6 minutes. This protection is active even if the boiler is switched off from the control panel.

Tap water circuit antifreeze protection

It is possible to ensure antifreeze protection for the tap water circuit with the 4 heating elements of 10W - 230V
connected to terminal X2 of the control unit. The antifreeze thermostat is connected in series with the heating
elements. The protection is activated when the temperature falls under 5°C and it turns off above 15°C.

DOMINA PLUS F 24 - 30 E

FERELLA EXTRA F 24 - 30 MEL

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Test operation

"Test" operation makes it possible to turn on the boiler in heating mode, but with idle time, flame modulation
and tap water operation turned off. It is possible to turn on "test" operation from the control panel on the boiler

by pressi
power. Operating knob 2, the display will blink and you can modify the heating power that will change instantly.

The power shown on the display will vary from 0 to 99. (100%) indicating the percentage change between the
minimum and maximum heating power. In the same way, with knob 3 you can change the ignition power that

will be set immediately. Pressing
operation can also be used to adjust the gas valve and to analyse the fumes.

N.B. To clear the boiler power during "Test" operation we recommend opening 1 or 2 taps.

Ionization current display

During "test" operation it is possible to display the ionization current. Pressing on the display will show the

3 times in 5 seconds. In this phase (5 min) LED 1 will blink and the display will show the heating

three times in 5 seconds quits the Test function (see power adj.). Test

ionization current in µA that is measured instantly. If you press
be shown. The ionization current can vary from 10 to 40µA (depending on the power). Under 5µA the flame is

not detected by the control card.

a second time, the heating power will again

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3.2 Operating diagram

DOMINA PLUS F 24 - 30 E

SUMMER (tap water)

 Hot water taps closed
 Boiler on "SUMMER"

WINTER (heating)

SUMMER (tap water)

 Hot water taps closed

 Hot water taps closed
 Flow meter off

 Boiler on "SUMMER"
 Heating delay of 2 min. performed

 Boiler on
 System pressure > 0.8 bar

 Electrical power supply on card 230V
 Boiler on stand-by "LED 5 ON"

 Fuse OK
 Room thermostat, heating potentiometer on call

 System pressure >0.8 bar
 Heating required "LED 4 ON"

 Boiler on stand-by "LED 5 ON"
 Heating circulator comes on

 Hot water tap opens 2.5 l/min
 Flow meter enabling signal
 Hot tap water required "LED 3 ON"

 Heating and tap water sensor enabling signal (NTC 10 Kohm at 25°C)
 Air pressure switch "NO" contact open, fan starts
 Intake and outlet ducts open, resistance under table limit.
 Pressure difference at air pressure switch >180 Pascal (18.00 mm approx.)
 Air pressure switch "NO" contact closed
 100°C safety thermostat enabling signal
 Electric discharge to ignition electrode
 Continuous voltage of 230V to the gas valve operators
 Main burner ignition
 Flame detection at ionization electrode within 10 sec. (safety time)
 End of electric discharge.
 Ionization working range

- 1 micro Ampere minimum for safety

- 2/3 micro Ampere minimum for working
 Ignition gas adjustment (natural gas or LPG) with appropriate parameter.

 Heating temperature adjustment trips; burner and
 Closing hot water tap, switching off burner.
fan switch off.
 End of requirement for hot tap water
 The circulator is working "LED 4 blinking" according
"LED 3 OFF"
to the dedicated parameter.
 Stand-by after hot tap water operation
 At the end of the 2 min delay, the burner re-ignites
"LED 4 blinking"
when required.
 Delay before starting heating of 2 min.

 Room thermostat trips on reaching the set
temperature.
 Boiler in post-circulation "LED 4 blinking"
 Heating circulator operates for 6 min.
(post-circulation).

 Boiler on
 Electrical power supply on card 230V
 Fuse OK
 System pressure >0.8 bar
 Boiler on stand-by "LED 5 ON"
 Hot water tap opens 2.5 l/min

 Hot water taps closed
 Flow meter off
 Heating delay of 2 min. performed
 System pressure > 0.8 bar
 Boiler on stand-by "LED 5 ON"
 Room thermostat, heating potentiometer on call
 Heating required "LED 4 ON"

 Heating circulator comes on
 Flow meter enabling signal
 Hot tap water required "LED 3 ON"

 Heating and tap water sensor enabling signal (NTC 10 Kohm at 25°C)
 Air pressure switch "NO" contact open, fan starts
 Intake and outlet ducts open, resistance under table limit.
 Pressure difference at air pressure switch >180 Pascal (18.00 mm approx.)
 Air pressure switch "NO" contact closed
 100°C safety thermostat enabling signal
 Electric discharge to ignition electrode
 Continuous voltage of 230V to the gas valve operators
 Main burner ignition
 Flame detection at ionization electrode within 10 sec. (safety time)
 End of electric discharge.
 Ionization working range

- 1 micro Ampere minimum for safety

- 2/3 micro Ampere minimum for working

 Ignition gas adjustment (natural gas or LPG) with appropriate parameter.

WINTER (heating)

 Closing hot water tap, switching off burner.
 End of requirement for hot tap water
"LED 3 OFF"
 Stand-by after hot tap water operation
"LED 4 blinking"
 Delay before starting heating of 2 min.

 Heating temperature adjustment trips; burner and
fan switch off.
 The circulator is working "LED 4 blinking" according
to the dedicated parameter.
 At the end of the 2 min delay, the burner re-ignites
when required.

 Room thermostat trips on reaching the set
temperature.
 Boiler in post-circulation "LED 4 blinking"
 Heating circulator operates for 6 min.
(post-circulation).

32

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12 4 3

5

RESET

°C °C

FERELLA EXTRA F 24 - 30 MEL

3.3 Control panel

Description of controls

The control panel is composed of 1 key, two
knobs and 2 displays.

When the key is pressed, there is a beep in
confirmation.

Key

1 ON-OFF / RESET / TEST

Pressing the key

Holding the

protection stays on). To turn it back on, press the

resets boiler operation after a shutdown.

key down for at least 5 sec. turns off the boiler. In this period, LED 5 blinks slowly (antifreeze

key again for at least 5 sec. and the boiler will reset

and display the software and memories.

Pressing the

key 3 times within 5 sec. automatically takes you to TEST operation (see Test

operation).

2 Setting system temperature / selecting Summer-Winter

Knob 2 is used to adjust the heating temperature and switch over between Summer/Winter (see
"adjustments" 3.4). It is necessary to set the heating temperature with the remote control if it is connected
on the boiler.

3 Hot water temperature setting

Use knob 3 to adjust the hot tap water temperature (see adjustments 3.4). It is necessary to set the tap
water temperature with the remote control if it is connected on the boiler.

4 Operating display

Indicates the boiler operating temperature on heating or hot water production, a flame (point at bottom lit
up) or any trouble.

5 Operating LED

LED

1

Burner on indicator (on steady)
Boiler in Test mode (blinking)

Shutdown indicator (steady light) Press RESET + code on the display

2

Shutdown fault indicator (blinking light) + code on the display

Hot water required (steady light)

3

Standby for heating after tap water operation
(blinking light)

Heating required (steady light)

4

Standby for heating after heating operation
(blinking light)

Electrical power supply

5

12345

Steady: boiler on
Blinking: boiler off but electric
power supplied

Version - 09.2002

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Information on the display

During normal operation, the boiler diagnostics control sends information on the state of the boiler and measures
the temperature of the water. This information is automatically shown on the display according to the type of
operation.

Operation LED on

Standby

Heating

Tap water

Standby for heating op.

(after tap water op.)

Standby for heating op.

(after heating op.)

Fault 1

(restore operation by pressing Reset)

Fault 2

(restore operation by removing fault)

L5

L5, L4 + L1

L5, L3 + L1

L5, L4 blinking

L5, L4 blinking

L5, L2

L5, L2 blinking

Display

Heating temp. (for example 40°C)

Heating temp. (for example 60°C)

Tap water temp. (for example 50°C)

Tap water temp. (for example 60°C)

Heating temp. (for example 70°C)

For example 1 (blinking display)

For example 37 (blinking display)

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3.4 Adjustments

Room temperature adjustment

Using the room thermostat, set the temperature desired in the rooms. Controlled by the room thermostat, the
boiler lights and heats the system water to the set system delivery setpoint temperature. The generator turns
off when the desired temperature in the rooms is reached. If the remote control (Ferroli) is used, the system
tries to modulate the ambient temperature according to the setting. In this passage the remote control can lower
the delivery temperature under the setting to maintain the ambient temperature: in any case, if the ambient
temperature exceeds the setting by 1°C the burner switches off and the circulator stays on for post-circulation.
The boiler also works with an external temperature sensor (see "sliding temperature"). If the room thermostat
or the remote control are not installed the boiler will keep the system at the set system delivery setpoint
temperature.

Summer/Winter selection

For the Summer/Winter selection, use knob 2 (see "control panel").

Turning it onto

position the heating temperature shown on the display will be 20 °C. In "Summer" mode the antifreeze function
stays on.

Turning it onto

(Summer) turns off the heating function. Only the hot tap water production is active. In this

(Winter) with a minimum temperature of 30°C turns on both heating and hot tap water.

Heating temperature setting

To set the system delivery temperature, turn the specific knob.

It can vary from a minimum of 30°C to a maximum of 85°C; however, it is advisable not to operate the boiler below
45°C (return temperature). Turning the knob sets the required temperature (clockwise to increase, anticlockwise
to decrease) that is shown on the display. During the setting, the display quickly blinks and once defined it stops
blinking after 2 sec. and goes back to showing the actual operating temperature.

If connecting to a remote timer control (optional), the system temperature is only governed with the remote
control. By turning the heating temperature control knob on the boiler, the temperature can only be displayed
and not changed.

Adjustment LED on Temperature on the display

System temperature

L5, L4

30 - 85 °C

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Hot water temperature adjustment

To set the system delivery temperature, turn the specific knob.

It can vary from a minimum of 30°C to a maximum of 65°C. Turning the knob sets the required temperature
(clockwise to increase, anticlockwise to decrease) that is shown on the display. During the setting, the display
quickly blinks and once defined it stops blinking after 2 sec. and goes back to showing the actual operating
temperature.

Adjustment LED on Temperature on the display

L5, L3Tap water temperature 40 - 65 °C

boiler, the temperature can only be displayed and not changed.

Adjusting the maximum heating output

To adjust the heating power, set the boiler on TEST operation (see "Test operation"). During the ignition phase,
the display shows the ignition power and, immediately afterwards, the heating power. Turn the heating
temperature control knob clockwise to increase the power or anticlockwise to decrease it. The display shows

Adjustment LED on

Heating system power

- knob 2 -

L1, L4, L1

blinking

set on the control panel, also with the remote control connected the system must be free of any errors.

Temperature on the display

0-100%

(Voltage at the valve to

change the power)

If connecting to a remote timer control
(optional), the system temperature
is only governed with the remote
control. By turning the tap water
temperature control knob on the

a percentage ranging from 0 to 100%
(the display blinks during the setting).
The figure shown on the display
indicates the percentage change
between the boiler's minimum and
maximum power. This adjustment is

Ignition power adjustment

To adjust the ignition power, set the boiler on TEST operation (see "Test operation"). During the ignition phase,
the display shows the ignition power and, immediately afterwards, the heating power. Turn the tap water
temperature control knob clockwise to increase the ignition power or anticlockwise to decrease it. The display

shows a percentage ranging from 0

Adjustment (TEST mode on) LED on

Ignition power

- knob 3 -

L1, L4, L1

blinking

Display

0-100%

(Voltage at the valve to

change the power)

to 100% (the display blinks during
the setting). The figure shown on the
display indicates the percentage

change between the boiler's
minimum and maximum power. This adjustment is set on the control panel, also with the remote control
connected.

Adjusting the heating t by changing the delivery-head of the circulator

The temperature drop t (difference in temperature of the heating water between the system delivery and return)
must be less than 20°C and this is obtained by changing the delivery-head of the circulator with its speed
changer (or with the switch).

36

Version - 09.2002

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DOMINA PLUS F 24 - 30 E

System delivery temperature °C

Outside temperature °C

20 10 0 -10 -20

90

80

70

60

50

40

30

20

1

2

3

4

57610 9 8

85

FERELLA EXTRA F 24 - 30 MEL

Sliding Temperature

When the optional outside sensor is installed the boiler adjustment system can work with "Sliding
Temperature." In this mode, the temperature of the heating system is governed according to the weather
conditions outside so as to ensure a high degree of comfort and energy savings throughout the year. In particular,
as the outside temperature increases the system delivery temperature decreases according to a specific
"compensation curve." With the Sliding Temperature adjustment, the temperature set becomes the maximum
system delivery temperature. It is recommended to set a maximum value to permit system adjustment
throughout its useful working range. The compensation curve can be modified with the knobs 2 and 3 (see
"control panel"). Turning knob 2 (see "control panel") and at the same time keeping the RESET key pressed
adjusts the compensation curve; whereas, turning knob 3 (see "control panel") and at the same time keeping
the RESET key pressed adjusts the parallel movement of the curves. To be able to make these adjustments

the boiler must be on standby (only

Adjustment LED on Display

L5Compensation curve - knob 2 0 - 10

L5Parallel shift of the curves (knob 3) 20 - 40 °C

LED 5 on). If you do not set the
compensation curve, leaving it on "0",
the boiler cannot work in "sliding
temperature" mode.

Compensation curves

Example of parallel curve shift

90

85

80

70

60

50

40

30

System delivery temperature °C

20

20 10 0 -10 -20

Outside temperature °C

710 9 8 6

90

85

80

70

60

50

40

30

System delivery temperature °C

20

5

4

3

2

1

9

10 8

20 10 0 -10 -20

Outside temperature °C

7

6

5

4

3

2

1

Version - 09.2002

If the boiler is hooked up with the optional remote control, the above adjustments (system temperature,
hot water temperature, compensation curve) can be made solely with the remote control. The user menu

on the boiler panel is disabled and functions solely as a display. In addition, the remote control will
always have priority for varying the delivery temperature to keep the room temperature at the required
level.

37

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DOMINA PLUS F 24 - 30 E

FERELLA EXTRA F 24 - 30 MEL

3.5 Operating parameter adjustment

Boiler parameter adjustment

These parameters can only be adjusted with the remote control connected on the card.

Copy day

Days

Change time

Programming

cursor

Heating operation

COPY

DAY

-

DAY/

PROGRAM

AUTO

MANUAL

DAY

1...7

+

d

Hot tap

water operation

1234567

12:00

Days Display

AUTO

MAN

0

C

27.

TEMP

123456

PROGRAM

Power level

Program

Antifreeze operation

/TEMP

Information /
RESET

Holidays

Change
temperature

Cursor
Program
selection

Simultaneously pressing keys 1 and 3 on the "PROGRAM" keypad for longer than 2 seconds brings up the
boiler parameter menu on the remote control screen.

On then pressing

settings.

The change is immediately active on leaving the menu.

38

you can scroll through the parameters, and with the and skeys you can edit the

i

0

1

Position

Tap water control selection

0 = Instantaneous production with twin heat

exchanger

1 = Production with external boiler

(not applicable)

Version - 09.2002

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DOMINA PLUS F 24 - 30 E

FERELLA EXTRA F 24 - 30 MEL

0

This parameter makes it possible to keep the timer-thermostat functions of the remote control even with zone
systems. The sliding temperature adjustment is set and controlled via the boiler control panel and the main card.

The remote control loses its room modulation function.

If the boiler is used without the remote control the boiler operation corresponds to selecting 1. But it will not
be necessary to set the value to 1.

0

2

3

Position

Selection of modulating timer-thermostat/
timer-thermosat On/Off for zone systems

0 = Modulating
1 = On/Off zone systems

Position

Natural gas / LPG selection

0 = Natural gas
1 = LPG

0

Selecting the "post-circulation" parameter, after a call for heating, the pump continues to work for the post­circulation time (6 min.).

Whereas, selecting "continuous pump," after a call for heating, the pump works constantly.

The pump is always turned off during tap water operation.

6

4

5

Position

Pump post-circulation / pump continuous
operation selection

0 = Post-circulation
1 = Continuous pump

Position

Post-circulation time adjustment.
Setting: 6min.

(range 1 to 255 min.)

Version - 09.2002

39

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DOMINA PLUS F 24 - 30 E

FERELLA EXTRA F 24 - 30 MEL

10

This permits changing the speed of increasing the delivery temperature.

100

Indicates the percentage difference between the minimum and maximum boiler power.

6

7

Position

System delivery temperature increase
adjustment. Setting: 10°C/min.

(range 1 to 20°C/min.)

Position

Heating power adjustment.
Setting: 100%
(range 0 to 100%.)

2

120

50

8

9

10

Position

Adjustment of idle time after switching off
heating.

Setting: 2 min.

(range 0 to 10 min.)

Position

Adjustment of idle time after tap water
operation

Setting: 120 sec.

(range 0 to 255 sec.)

Position

Adjustment of power during ignition phase.
Setting: 50%

(range 0 to 100%.)

Indicates the percentage difference between the minimum and maximum boiler power.

40

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DOMINA PLUS F 24 - 30 E

FERELLA EXTRA F 24 - 30 MEL

0

30

Used to make a parallel shift of the compensation curve.

To quit the menu, press keys 1 and 3 simultaneously or wait to quit automatically after 1 minute.

11

12

Position

Compensation curve selection.
Setting: 0 (adjustment turned off)

(range 1 to 10)

Position

Compensation curve fixed point adjustment
Setting: 30

(range 20 to 40)

Version - 09.2002

41

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DOMINA PLUS F 24 - 30 E

FERELLA EXTRA F 24 - 30 MEL

Checking operating data log

With a remote control installed, pressing keys 1 and 2 simultaneously for longer than 2 seconds takes you
to the operating data log menu.

Storing the last 8 faults.

The display on the remote control shows the storage sequence of the faults and their code

Error

F

Position

code

F011
F33 2
F37 3
F06 3
F015
F016
F09 7
F39 8

By pressing the

Position 1 indicates the last fault that occurred. When there is a fault, this is saved at point 1 , while the ones
already saved are moved on by one place.

key you can scroll through the numbers of the faults.

i

42

Version - 09.2002

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DOMINA PLUS F 24 - 30 E

Fault Possible cause

Heating sensor fault  Sensor damaged

 Incorrect wiring

(short-circuit)

Heating sensor fault  Sensor damaged

 Incorrect wiring

(broken)

Tap water sensor fault  Sensor damaged

 Incorrect wiring

(short-circuit)

Display

Tap water sensor fault  Sensor damaged

 Incorrect wiring

(broken)

Mains voltage  The mains voltage is

under 185 VAC

Mains frequency  The frequency exceeds the

tolerance of +/- 5%

Card trouble  Defective hardware

Low system pressure  System empty

 Water pressure switch not

connected or damaged

RESET key jammed  ON/OFF button

damaged

External sensor fault  Damaged sensor

 Sensor wiring

shorted

FERELLA EXTRA F 24 - 30 MEL

4. Unit self-diagnosis

Fault Diagnosis

The boiler is equipped with an advanced self-diagnosis system. In the event of trouble with the boiler, the display

will show the fault code. There are faults that in order to restore operation it suffices to press RESET
the boiler fails to start, it is necessary to resolve the fault indicated by the operating LEDs (faults from 1 to 25);

other faults cause temporary shutdowns that are automatically reset as soon as the value comes back within
the boiler's normal working range (faults from 30 to 39). When the boiler starts functioning normally again, the
display stops blinking and the fault code disappears.

; if

LED

Steady light

steady light

Blinking light

steady light

List::

Fault Possible cause

Display

No burner ignition  No gas

Safety thermostat trips  Damaged thermostat

Air pressure switch (with

contacts closed before

turning on the fan)

Air pressure switch (fails to

close the contacts within

60 sec. of turning on the fan)

Fault CureDISPLAY

Boiler shutdown

Low system pressure

 Detection or ignition

electrode fault

 Defective gas valve

 No water circulation in the

system

 Air pressure switch contact

closed

 Incorrect wiring to the air

pressure switch

 Air pressure switch contact

open

 Incorrect wiring to the air

pressure switch

 Wrong diaphragm

 Flue not correctly sized

Make sure that the gas cocks ahead of the boiler and on the
meter are open.
Press button 1 "Reset".
In case of repeated shutdowns, contact the nearest assistance
centre

Fill the system to 1-1.5 bar cold by means of the specific cock
located in the boiler.
Close the cock after use.

Air pressure switch (closes

and opens the contacts

5 times within 60 sec. of

the ignition phase)

Fault on the flame control

circuit

No burner ignition  Incorrect gas valve

Card trouble  Interference caused by the

From

to

 Wrong diaphragm

 Flue not correctly sized

 Interference caused by

the electric mains

 Card microprocessor

damaged

connection

 Broken wiring of gas valve

electric mains

 Card microprocessor

damaged

Version - 09.2002

43

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37047 SAN BONIFACIO - VR - ITALY

tel. [phone] - tlx 480172

fax [phone]

code 354M011/0