Ferroli PEGASUS F2 N 2S Troubleshooting guide

PEGASUS F2 N 2S
CAST IRON GAS BOILER
for heating with electronic
ignition and flame control
INSTRUCTIONS FOR USE,
INSTALLATION
AND MAINTENANCE
cod. 3544309/0 ediz. 01/2003

2
This symbol indicates “Caution”
and is placed next to all safety
warnings. Strictly follow these
instructions in order to avoid
danger and damage to persons,
animals and things.
This symbols calls attention to a
note or important notice
• Carefully read the warnings in this
instruction booklet since they provide
important information on safe installa-
tion, use and maintenance.
• This instruction booklet is an integral
part of the product and must be carefully
kept by the user for future reference.
• If the unit is sold or transferred to
another owner or if it is to be moved,
always make sure that the booklet
accompanies the boiler so that it can
be consulted by the new owner and/or
installer.
• Installation and maintenance must
be carried out by professionally quali-
fied personnel, according to current
regulations and the manufacturer’s
instructions.
• Incorrect installation or poor mainte-
nance 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
• Before carrying out any cleaning or
maintenance operation, disconnect the
device from electrical power supply
using the switch and/or the special
cutoff devices.
• In case the unit breaks down and/or
functions poorly, deactivate it, do not
make any attempt to repair it or directly
intervene. Contact professionally
qualified personnel.
• Any repair/replacement of products
must only be carried out by qualified
professional personnel using exclusively
genuine parts. Failure to comply with
the above could affect the safety of
the unit.
• Yearly maintenance carried out by
qualified personnel is essential for
guaranteeing good operation of the
unit.
• This unit must only be used for the
purpose for which it was designed. Any
other use is considered improper and
therefore hazardous.
• After removing the packing, check the
integrity of the contents.
• Packing materials must not be left
within the reach of children as they are
potentially hazardous.
• In case of doubt do not use the unit,
and contact the supplier.
Certification
The CE marking demonstrates that Ferroli
gas units conform to the requirements
contained in the applicable European
directives.

Pegasus F2 N 2S
3
1. Operating instructions............................................................................4
1.1 Introduction.............................................................................................................4
1.2 Control panel ..........................................................................................................4
1.3 Turning on and off...................................................................................................5
1.4 Adjustments ............................................................................................................5
1.5 Maintenance............................................................................................................6
1.6 Anomalies................................................................................................................6
2. Installation ..............................................................................................7
2.1 General Instructions................................................................................................7
2.2 Place of installation .................................................................................................7
2.3 Plumbing connections.............................................................................................7
2.4 Gas connection .......................................................................................................8
2.5 Electrical Connections ............................................................................................9
2.6 Connection to the flue..........................................................................................10
2.7 Installing module generators................................................................................10
3. Service and maintenance......................................................................16
3.1 Adjustments ..........................................................................................................16
3.2 System start-up.....................................................................................................19
3.3 Maintenance..........................................................................................................20
3.4 Troubleshooting ....................................................................................................24
4 Technical characteristics and data .........................................................26
4.1 Dimensions and connections ................................................................................26
4.2 General view and main components ....................................................................27
4.3 Technical data table ..............................................................................................28
4.4 Diagrams ...............................................................................................................29
4.5 Wiring diagrams....................................................................................................30

4
Pegasus F2 N 2S
fig. 1
1. OPERATING INSTRUCTIONS
1.1 Introduction
Dear Customer,
Thank you for choosing Pegasus F2 N 2S, a FERROLI floor-standing boiler featuring advanced
design, cutting-edge technology, high reliability and quality construction. Please read this manual
carefully and keep it for future reference.
Pegasus F2 N 2S is a high-efficiency heat generator for central heating running on natural or liquid gas
(configurable at installation time) and regulated by an advanced electronic control system.
The boiler shell consists of cast-iron elements 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 outfit moreover includes an automatic boiler air vent valve, a 2-stage control thermostat,
a safety thermostat and flue thermostat.
Thanks to the electronic ignition and flame control system, unit operation is for the most part
automatic.
The user only has to set the system temperature by means of the control thermostat.
1.2 Control panel
To access the control panel, lift the front door.
Key
1Arrangement for thermostatic controller
2Boiler pressure thermometer
3Manual reset safety thermostat cover
4 Flue thermostat cap
5Plug
6Flame control reset button with block light
72-stage boiler control thermostat
80 - 1 - TEST switch
1234567 8

Pegasus F2 N 2S
5
1.3 Turning on and off
Ignition
• Open the gas valve ahead of the boiler.
• Turn on or insert any switch or plug ahead of the boiler
• Turn the boiler switch “8” onto 1 (Fig. 1).
• Turn knob “7” to the preselected temperature and any room thermostat to the desired temperature
value. At this point, the burner will light and the boiler begins to function automatically, controlled
by its adjustment and safety devices.
• If the boiler is equipped with an electronic thermostatic controller mounted at position 1 of Fig. 1,
the user must also take into account the manufacturer’s instructions.
If, after correctly carrying out the lighting procedure, the burners do not light and the pushbutton
light “6” comes on, wait about 15 seconds and then press the above-mentioned pushbutton.
The flame controller reset in this way will then repeat the ignition cycle. If the burners do not
light after a number of attempts, consult the anomalies paragraph.
In case of an electrical power failure while the boiler is working, the burners will go out and
re-ignite automatically when power is restored.
Turning off
Close the gas cock ahead of the boiler, turn knob “8” onto the 0 position and disconnect the
electrical power.
To avoid damage caused by freezing during long shutdowns in winter, it is advisable to drain all
water from the boiler and the system; or add a suitable antifreeze to the heating system.
The boiler switch “8” has 3 positions, “0-1-TEST”; the first two have the on-off function, the third
(unstable) must only be used for service and maintenance purposes.
1.4 Adjustments
System temperature adjustment
Turn knob “7” (Fig. 1) clockwise to increase the heating water temperature, turn anticlockwise to
decrease it. The temperature can be varied from a minimum of 30°C to a maximum of 90°C. However,
it is advisable not to operate the boiler below 45°C.
Room temperature adjustment (with optional room thermostat)
Using the room thermostat, set the temperature desired in the rooms. Controlled by the room
thermostat, the boiler lights and delivers water to the system at the temperature set by boiler
adjustment thermostat “7” (Fig. 1). The generator turns off when the desired temperature in
the rooms is reached.
If the room thermostat is not installed the boiler will keep the system at the temperature set
by the boiler control thermostat.
Water system pressure adjustment
The filling pressure with system cold, read on boiler hydrometer (detail 2 in Fig.1), must be about 1.0 bar.
If, during operation, the system pressure falls (caused by the evaporation of gas dissolved in the water) to
values below the minimum described above, the user must bring it back to the initial value by operating
the filling cock. At the end of the operation always close the filling cock.

6
Pegasus F2 N 2S
1.5 Maintenance
The user must have the heating system serviced by qualified personnel at least once a year and combustion
checked at least every two years. Consult chapter 3.3 of this manual for more information.
The boiler casing, panel and aesthetic parts can be cleaned with a soft damp cloth, possibly soaked in
soapy water. Do not use any abrasive detergents and solvents.
1.6 Anomalies
Listed below are the anomalies that can be caused by simple, user-solvable problems.
Before calling the assistance service, check that the problem is not due to there being no
gas or electricity.
Boiler blocked by the flame controller Make sure that the gas cocks ahead of the boiler and on the meter
are open.
Press the lit pushbutton-indicator light.
In case of repeated shutdowns, contact the nearest assistance centre.
Symbol Fault Cure
Boiler shutdown due to insufficient system
pressure (only if a water pressure switch is
installed on the system)
Fill the system to 1-1.5 bar cold by means of the system filling cock.
Close the cock after use.
Boiler shutdown due to water
overtemperature
Unscrew the safety thermostat cover and press the button below.
In case of repeated shutdowns, contact the nearest assistance centre.
Boiler shutdown due to insufficient
combustion products evacuation.
Unscrew flue thermostat cover and press the button below.
In case of repeated shutdowns, contact the nearest assistance
centre.

Pegasus F2 N 2S
7
2. INSTALLATION
2.1 General Instructions
This device must only be used for the purpose for which it is specially designed.
This unit is designed to heat water to a temperature below boiling point at atmospheric
pressure and must be connected to a heating system and/or a water supply system for
domestic use, compatible with its performance, characteristics and its heating capacity.
Any other use is considered improper.
THE BOILER MUST ONLY BE INSTALLED BY QUALIFIED PERSONNEL, IN ACCORDANCE WITH ALL
THE INSTRUCTIONS GIVEN IN THIS TECHNICAL MANUAL, THE PROVISIONS OF CURRENT LAW,
ANY LOCAL REGULATIONS AND THE RULES OF PROPER WORKMANSHIP.
Incorrect installation can cause damage or physical injury for which the manufacturer declines
any responsibility.
2.2 Place of installation
This unit is an “open chamber” type and can only be installed and operated in permanently ventilated
rooms. An insufficient flow of combustion air to the boiler will affect its normal operation and fume
evacuation. Also, the fumes forming under these conditions (oxides) are extremely harmful to health
if dispersed in the domestic environment.
Therefore the place of installation must be free of dust, flammable materials or objects or corrosive
gases. The room must be dry and not subject to freezing.
When positioning the boiler, leave sufficient space around it for normal maintenance activities.
2.3 Plumbing connections
The heating capacity of the unit should be previously established by calculating the building’s heat
requirement according to current regulations. For good operation and long life of the boiler, the
plumbing system must be well proportioned and always complete with all those accessories that
guarantee regular operation and running.
If the delivery and return pipes follow a path where air pockets could form in certain places, it is
advisable to install vent valves at these points. Also, install a discharge device at the lowest point in
the system to allow its complete emptying.
If the boiler is installed at a lower level than the system, it is advisable to provide a flow-stop valve to
prevent the natural circulation of system water.
The temperature drop between the delivery manifold and the return to the boiler should not
exceed 20°C.
Do not use the water system pipes to earth electrical appliances.
Before installation, carefully wash all the pipes of the system to remove residues or impurities that
could affect the unit’s good working.
Make the connections to the corresponding connections as shown in Fig. 2.

Pegasus F2 N 2S
8
It is advisable to install on-off valves between the boiler
and heating system allowing the boiler to be isolated
from the system if necessary.
Make the boiler connection in such a way that its
internal pipes are free of stress.
fig. 2
B
Characteristics of the water system
In the presence of water harder than 25° Fr, we recommend the use of suitably conditioned water in order
to avoid possible scaling in the boiler, caused by hard water, or corrosion produced by aggressive water.
It should be remembered that, because of its low thermal conductivity, even scaling of just a few mm thick
causes significant overheating of the boiler walls with consequent serious problems.
Water treatment is indispensable in the case of very large systems (containing large amounts of water) or
with frequent introduction of replenishing water in the system. If partial or total emptying of the system
becomes necessary under these conditions, it is advisable to refill it with treated water.
Filling boiler and system
The filling pressure with system cold system must be about 1 bar. If, during operation, the system
pressure falls (caused by evaporation of gas dissolved in the water) to a value below the minimum
described above, the user must bring it back to the initial value. For correct operation of the boiler,
when hot, its pressure must be about 1.5-2 bar.
2.4 Gas connection
Before making the connection, ensure that the unit is arranged for operation with the type of
fuel available and carefully clean all the pipes of the gas system to remove any residues that
could affect good functioning of the boiler.
The gas must be connected to the relative connector (see Fig. 2) in conformity with current standards,
with rigid metal pipes or with continuous flexible s/steel wall tubing, placing a gas cock between the
system and the boiler. Make sure that all the gas connections are tight.
The capacity of the gas meter must be sufficient for the simultaneous use of all equipment connected
to it. The diameter of the gas pipe leaving the boiler does not determine the diameter of the
pipe between the unit and the meter; it must be chosen according to its length and loss of head,
in conformity with current standards.
Do not use the gas pipes to earth electrical appliances.
Pegasus F2 N 51 2S
Pegasus F2 N 68 2S
Pegasus F2 N 85 2S
Pegasus F2 N 102 2S
550
640
720
800
B
180
180
200
200
C
43
46
44
42
D
35
38
36
34
E
Type and model
3/4”
3/4”
3/4”
3/4”
a3
Inlet
gas
1” 1/2
1” 1/2
1” 1/2
1” 1/2
a2
Delivery
Heating
1” 1/2
1” 1/2
1” 1/2
1” 1/2
a1
Return
Heating
Rear View

Pegasus F2 N 2S
9
2.5 Electrical Connections
Connection to the electrical grid
The boiler must be connected to a single-phase, 230 Volt-50 Hz electric line.
The unit’s electrical safety is only guaranteed when correctly connected to an efficient earthing
system executed according to current safety standards. Have the efficiency and suitability of
the earthing system checked by professionally qualified personnel. The manufacturer is not
responsible for any damage caused by failure to earth the system. Also make sure that the
electrical system is adequate for the maximum power absorbed by the unit, as specified on
the boiler dataplate, in particular ensuring that the section of the system’s cables is suitable
for the power absorbed by the unit.
The boiler is prewired and supplied with a connector located inside the control panel, arranged for
connection to an electronic thermostatic controller (see wiring diagrams in paragraph 4.5). In addition,
it is equipped with a three-pole cable for connection to the electricity line. The mains connections
must be made with a permanent connection and equipped with a bipolar switch whose contacts have
a minimum opening of at least 3 mm, interposing fuses of max. 3A between the boiler and the line. It
is important to respect the polarities (LINE: brown wire / NEUTRAL: blue wire / EARTH: yellow-green
wire) in making connections to the electrical line.
Access to the electrical terminal board and internal components of the
control panel
To access the electrical components inside the control panel, follow the sequence in
Fig. 3 - 4 - 5 - 6.
The layout of the terminals for the various connections is given in the wiring diagrams in the
technical data chapter.
Fig. 3 - Unscrew the 2 self-tapped screws holding
the boiler cover.
Fig. 4 - Lift by pressing upwards and take off the cover
that is held at the sides of the boiler by pins.
Fig. 5 - Unscrew and take out the two screws and both
plates holding the control panel.
Fig. 6 - Turn the control panel forwards.

Pegasus F2 N 2S
10
2.6 Connection to the flue
The diameter of the flue connection pipe must not be less than that of the connection on the
anti-backflow device. Starting from the anti-backflow device it must have a vertical section at least
50 cm long. Current standards must be complied with regarding the dimensioning and installation
of the flues and connection pipe.
The diameters of the anti-backflow device collars are given in the table of Fig. 2.
2.7 Installing module generators
INSTALLATION MUST ONLY BE PERFORMED BY QUALIFIED PERSONNEL, IN ACCORDANCE WITH
ALL THE INSTRUCTIONS GIVEN IN THIS TECHNICAL MANUAL, THE PROVISIONS OF CURRENT
LAW, THE PRESCRIPTIONS OF UNI AND CEI STANDARDS, ANY LOCAL REGULATIONS AND THE
RULES OF PROPER WORKMANSHIP.
General Warnings
It is advisable to install on-off valves between the boiler (module) and the system allowing the
boiler to be isolated from the system if necessary. In this case each boiler must be fitted with a
safety valve operating on the delivery pipe.
If the delivery and return pipes follow a path where air pockets could form in certain places, it is
advisable to install vent valves at these points.
The heating water temperature drop, the difference between the system delivery and return temperature,
must be lower than 20°C. To prevent condensation in the boiler and the associated damage.
Evacuate the products of combustion by means of a flue, whose cross-section must conform to current
standards and anyhow be no less than that of the coupling to the module generator fume manifold. If it is
wished to use manifolds to discharge the fumes, see the charts of Fig. 8 and 9.
All the couplings between the boiler and the flue must be airtight.
The capacity of the gas meter must be sufficient for the simultaneous use of all the generators
connected to it.
Make the various boiler connections in such a way that their pipes are free of mechanical stress.
Make the gas connections of the single generators in accordance with current regulations.
Any additional sensitive elements of the system’s control
and safety devices, temperature sensor, pressure
switch, thermostat bulb, etc., must be located on the
delivery pipe within 40 cm. of the rear wall of the
boiler casing (see Fig. 7).
40 cm max.
System delivery
System return
fig. 7

Pegasus F2 N 2S
11
Characteristics of the system water
In the presence of water harder than 25° - 30° Fr, we recommend the use of suitably conditioned
water for the heating system in order to avoid possible scaling in the boiler, caused by hard water,
or corrosion produced by aggressive water. It should be remembered that, because of its low
thermal conductivity, even scaling of just a few mm thick causes significant overheating of the boiler
walls with consequent serious problems.
Water treatment is indispensable for the heating system in the following cases:
A)very large systems (containing large amounts of water):
B) frequent introduction of replenishing water in the system, in the case of draining the
system either partially or totally.
Positioning the module generators and connecting the flues to the manifold
The set of module generators can comprise at most 4 units; depending on controller requirements they
can be arranged with the modules either facing each other or in a line.
Position the generators and connect the fume extraction pipes according to the diagrams and data
given in the charts of Fig. 8 - 9. Seal the various pipe joints.
SIDE VIEW PLAN VIEW 2 MODULES PLAN VIEW 3 MODULES PLAN VIEW 4 MODULES
STANDARD BOILER
2 MODULES 3 MODULES 4 MODULE
HEAT GENERATORS WITH MODULES IN LINE COMPREHENSIVE OF FUME MANIFOLD
100
Ø
Ø
H ±40
100 Ø
100
100
1900
L
100
Ø
1900
100
L
L
1900
PEGASUS F2 N 51 2S
PEGASUS F2 N 68 2S
PEGASUS F2 N 85 2S
PEGASUS F2 N 102 2S
102
136
170
204
112,0
149,6
187,0
224,0
550
640
720
800
1700
1700
1725
1725
250
250
300
300
Output
kW
Heating
power
kW
LHØ
153
204
255
306
168,0
224,4
280,5
336,0
1200
1380
1540
1700
1725
1725
1750
1750
300
300
350
350
LHØ
204
272
340
408
224,0
299,2
374,0
448,0
1200
1380
1540
1700
1750
1750
1775
1755
350
350
400
400
LHØ
HEAT GENERATORS WITH FACING MODULES COMPREHENSIVE OF FUME DUCTING CHAMBER
CALDAIA BASE
PEGASUS F2 N 51 2S
PEGASUS F2 N 68 2S
PEGASUS F2 N 85 2S
PEGASUS F2 N 102 2S
102
136
170
204
112,0
149,6
187,0
224,0
1200
1380
1540
1700
1690
1690
1715
1715
250
250
300
300
LHØ
Ø
H
±40
100
Ø
H
±40
100
L
100
Ø
H
±40
100
L
100100
153
204
255
306
168,0
224,4
280,5
336,0
1850
2120
2360
2600
1715
1715
1740
1740
300
300
350
350
LHØ
204
272
340
408
224,0
299,2
374,0
448,0
2500
2860
3180
3500
1740
1740
1765
1765
350
350
400
400
LHØ
L
Output
kW
Heating
power
kW
Output
kW
Heating
power
kW
Output
kW
Heating
power
kW
Output
kW
Heating
power
kW
Output
kW
Heating
power
kW
fig. 8
fig. 9

Pegasus F2 N 2S
12
Electrical connection of module generators
Each generator comprising the modular assembly is supplied pre-wired for both the adjustments and
the safety devices. It can therefore operate on its own (see wiring diagrams of paragraph 4.5). Connect
each generator to a single-phase electric line of 230 V ~ 50 Hz, neutral phase, via a terminal board or
regular plug, inserting fuses max. 2 A between the boiler and the line.
It is always important to connect each generator to a good earthing system.
If you want the generators forming the modular assembly to work in cascade, you will need to
use an electronic sequence controller.
Electronic sequence controller (supplied on request)
Each generator forming the modular assembly is fitted for installing an electronic sequence controller
(Fig. 10) that can be secured to the instrument panel by simply removing the plug 1 (Fig. 1). To access
the components inside the instrument panel, see paragraph 2.5.
A single sequence controller is needed for each set of module generators.
The instructions manual for connecting, adjusting and programming the electronic sequence controller
as well as for the various types of system is contained in the controller package.
Fundamental functions of the electronic sequence controller
- Reduction interlocked with outside temperature (climate control).
- Programming on two different temperature levels (economy and comfort).
- Daily programming with up to three actions on one level and three on the other.
- Setting the daily program for the whole week.
- Rotating the action sequence every 24 hours to distribute module wear.
- Smart forced starting.
- Smart ON-OFF time control in the action cycle.
- Checking pump starting according to the outside temperature.
- Self-diagnosis for malfunctioning.
fig. 10

Pegasus F2 N 2S
13
Application systems
The 2 application systems are described here.
System 1: 4 modular generators with no hot water production
Application
Direct delivery heating with at most 4 modular generators.
Key:
C1 - C2 - C3 - C4 = Modular generators
V1 - V2 - V3 - V4 = 3-way valves
T5 = Delivery manifold sensor
T3 = External sensor
P1 = Heating circulation pump
T3
T5
P1
C1 C2 C3 C4
W6050C
T3
T5
P1
C1 C2 C3 C4
W6050C
V1 V2 V3 V4
fig. 11a
fig. 11b

Pegasus F2 N 2S
14
System 2: 4 modular generators with hot water production
Application
Direct delivery heating with at most 4 modular generators with hot water production via
diverter valve.
Key:
C1 - C2 - C3 - C4 = Modular generators
V1 - V2 - V3 - V4 = 3-way valves
B = Boiler
VD = Diverter valve
T3 = External sensor
T4 = Modular generators
T5 = Delivery manifold sensor
P1 = Heating circulation pump
P2 = Boiler circulation pump
When the system is producing water for domestic use the sequence governor will always
control just one generator for this function, which in the diagrams of Fig. 12a - 12b is C1
T4
T5
P1
C1 C2 C3 C4
W6050C
P2
VD
BT3
T4
T5
P1
C1 C2 C3 C4
W6050C
P2
VD
BT3
V1 V2 V3 V4
fig. 12a
fig. 12b

Pegasus F2 N 2S
15
Control and check panel for module generators in sequence
(supplied on request)
In order to make the electric connection between the four-stage sequence governor W6050C, the
module generators Pegasus F2 N 2S and the various system components more straightforward and
functional, we have made a control and check panel for heating plants.
It is supplied pre-wired and comprehensive of sequence governor, fuse, indicator lamps, and
switches making it possible to check and select every possible system of using the sequence
governor W6050C.
The panel, which contains the terminal blocks to connect sensors, pumps, diverter valve and generators
in sequence, is supplied together with cable clamps.
Panel specifications:
- Dimensions 310x420x h 150
- Protection rating IP 65
- Twin key door locking
- Cable clamps: No.8 PG9 + No.2 PG13.5
AUTO
FUSE
MANUAL 000
C1 C2 C3 C4
C1 C2 C3 C4
Symbols key Summer / Winter
Generators in sequence
Diverter valve
Heating circulator
Boiler circulator
On / Off
fig. 13

Pegasus F2 N 2S
16
3. SERVICE AND MAINTENANCE
3.1 Adjustments
All adjustment and conversion operations must be carried out by Qualified Personnel.
The manufacturer declines any responsibility for damage or physical injury caused by unqualified and
unauthorized persons tampering with the device.
Adjusting the burner gas pressure
The Pegasus F2 N 2S boilers are made to burn natural or liquid gas. The pressure setting and
test are performed in the factory.
However, as there may be changes in supply pressure, at the time of the first ignition it will be
necessary to check and perhaps adjust the pressure at the nozzles, observing the values given in
the technical data chart in paragraph 4.3.
The operations for adjusting the pressure are performed with the boiler working, using the pressure
control on the 2-stage gas valves (see Fig. 14).
Preliminary operations:
1Ignite the boiler and turn the control thermostat knob onto minimum.
2Connect a pressure gauge to the pressure point on the gas manifold pipe of the burner
assembly (see part 15 in Fig. 24).
3Take off the cover protecting the pressure regulator 4 (Fig. 14).
Adjusting the minimum power (1st stage)
1Slowly turn the adjustment thermostat knob clockwise as far as the 1st click; the gas valve will thus
be supplied solely on connections A and B (see Fig. 14).
2Turn the screw 6 (Fig. 14), checking that the pressure corresponds to the values of the technical
data chart in paragraph 4.3.
Adjusting the maximum power (2nd stage)
1Turn the adjustment thermostat knob onto maximum; the gas valve will now be supplied on
connections A, B and C (see Fig. 14).
2Turn the screw 5 (Fig. 14), checking that the pressure corresponds to the values of the technical
data chart in paragraph 4.3.
For model 102 the adjustment operations must be performed uniformly on the two pressure
regulators.
The gas pressures measured at the burner gas manifold should be read at least 30 seconds after
making the adjustments, i.e. when the flame has stabilized.
On completing the adjustment operations, turn the burner on and off 2 - 3 times with the adjustment
thermostat and check that the pressure values are the ones you have just set; if this is not so, you need
to make another adjustment to bring the pressures to the right values.
Gas supply conversion
The unit can function with either Natural gas (G20-G25) or liquid gas (G30-G31) and is factory-set for use
with natural gas, as clearly shown on the packing and dataplate. Whenever the unit has to be used with
a different gas, a conversion kit will be required, proceeding as follows:

Pegasus F2 N 2S
17
From natural to liquid gas
1Replace the nozzles at the main burner and pilot light, inserting the nozzles specified in the
technical data table in chap. 4.3.
2Remove the small plug 3 (Fig. 14) from the gas valve, screw the ignition “STEP” regulator 2, contained
in the conversion kit, onto the valve and put the plug 3 back onto the regulator.
3Adjust the burner gas pressures, for minimum and maximum power as described in the above
paragraph, setting the values given in the technical data chart in paragraph 4.3.
4For model 102, equipped with 2 gas valves, steps 2 and 3 must be carried out on both valves.
5Apply the sticker, contained in the conversion kit, near the dataplate as proof of the conversion.
From liquid to natural gas
Carry out the same operations explained above, taking care to remove the ignition “STEP” regulator 2
(Fig. 14) of the gas valve; the plug 3 (Fig. 14) must be fitted straight onto the valve.

Pegasus F2 N 2S
18
To measure the burner gas pressure, use the pressure point on the gas manifold pipe of the
burner assembly (see part 15 in Fig. 24)
Main components key
1 Pressure point upstream from the valve
2 Ignition “STEP” regulator for liquid gas
3 Plug
4 Safety cap
5 Pressure adjustment screw for maximum power
6 Pressure adjustment screw for minimum power (1st stage)
7 “O RING”
fig. 14
B
C
A
Opening the safety cap
Decrease
Increase
Valve
Honeywell
VR 4601 QB
--
VR 4611 QB
Electrical connections key
= Connections powered for minimum power (1st stage)
= Connections powered for maximum power (2nd stage)

Pegasus F2 N 2S
19
3.2 System start-up
System start-up must be carried out by Qualified Personnel.
The following operations and checks are to be made at the first ignition, and after all maintenance work
that involved disconnecting from the systems or work on safety devices or parts of the boiler.
Before lighting the boiler:
• Open any on-off valves between the boiler and the system.
• Check the airtightness of the gas system, proceeding with caution and using a soap and water
solution to detect any leaks in connections.
• Fill the water system and make sure that all air contained in the boiler and the system has been vented
by opening the air vent valve on the boiler and any vent valves on the system.
• Make sure there are no water leaks in the system or boiler.
• Make sure the electrical system is properly connected.
• Make sure that the unit is connected to a good earthing system.
• Make sure that the pressure and gas flow values are those required for heating.
• Make sure there are no flammable liquids or materials in the immediate vicinity of the boiler.
Lighting the boiler
• Open the gas valve ahead of the boiler.
• Vent the air from the pipe ahead of the gas valve.
• Turn on or insert any switch or plug ahead of the boiler.
• Turn the boiler switch (pos. 8 - Fig. 1) onto 1.
• Turn knob 7 (Fig. 1) to a value above 50°C and that of a possible room thermostat to the desired
temperature value. At this point, the burner will light and the boiler begins to function automatically,
controlled by its adjustment and safety devices.
If, after correctly carrying out the lighting procedure, the burners do not light and the pushbutton
light comes on, wait about 15 seconds and then press the above-mentioned pushbutton.
The reset controller will repeat the ignition cycle. If the burners do not light after the second
attempt, consult paragraph 3.4 “Troubleshooting.”
The boiler switch 8 has 3 positions, “0-1-TEST”; the first two have the on-off function, the third
(unstable) must only be used for service and maintenance purposes.
In case of an electrical power failure while the boiler is working, the burners will go out and
re-ignite automatically when power is restored.
Checks during operation
• Check the airtightness of the fuel circuit and water systems.
• Check the efficiency of the flue and fume ducts while the boiler is working.
• Check that the water is circulating properly between the boiler and the systems.
• Check the proper ignition of the boiler by performing various tests, turning it on and off with
the room thermostat or boiler thermostat.
• Make sure that the fuel consumption indicated on the meter corresponds to that given in the
technical data table in chap. 4.

Pegasus F2 N 2S
20
Turning off
To temporarily turn the boiler off, just turn the boiler switch 8 (Fig. 1) onto 0.
To turn the boiler off for an extended period:
• Turn the knob of the boiler switch 8 (Fig. 1) onto 0;
• Close the gas cock ahead of the boiler;
• Disconnect the electrical power to the unit;
To avoid damage caused by freezing during long shutdowns in winter, it is advisable to drain all
water from the boiler and the system; or add a suitable antifreeze to the heating system.
3.3 Maintenance
The following operations must only be carried out by Qualified Personnel.
Seasonal inspection of the boiler and flue
It is advisable to carry out the following checks at least once a year:
• The control and safety devices (gas valve, thermostats, etc.) must function correctly.
• The fume ducts must be free of obstructions and leaks.
• The gas and water systems must be airtight.
• The burner and boiler shell must be clean. Follow the instructions in the next paragraph.
• The electrodes must be free of scale and properly positioned (see Fig. 21).
• The water pressure in the cold water system must be about 1 bar; otherwise, bring it to that value.
• The expansion tank, if present, must be filled.
• The gas flow and pressure must correspond to that given in the respective tables.
• The circulating pumps must not be blocked.
Safety devices
The Pegasus F2 N 2S boiler is equipped with devices that guarantee safety in the event of
operating trouble.
Temperature limiter (safety thermostat) and manual reset
This device prevents the water temperature in the system from exceeding boiling point. The maximum
intervention temperature is 110°C.
Reset of the temperature limiter can only occur with cooling of the boiler (the temperature must
drop by at least 10°C) and identification and consequent elimination of the problem that caused
the shutdown. To reset the temperature limiter you will need to unscrew the cover 3 (Fig. 1)
and press the button below.
Flue gas safety sensor device (flue gas thermostat - manual reset)
The boiler is fitted with device for checking the discharge of the products of combustion. If any
anomalies arise in the flue gas discharge system, with the consequent emission of burnt gas into the
room, the appliance will shut down. To measure and control the temperature of the flue gas, the
wind-protection hood is fitted with a temperature sensor bulb.
Any release of burnt gas into the room causes the temperature measured by the bulb to increase,
and as a consequence the boiler is shut-down within 2 minutes, by cutting off the supply of
gas to the burner assembly.
If the flue gas sensor is activated, unscrew the protective cover (4, fig. 1) on the control panel and
manually reset the device. The boiler will recommence operation.
If, in the event of failure, the sensor needs to be replaced, only use original accessories, and check that
the electrical and bulb connections are performed correctly.
The flue gas sensor must not be bypassed under any circumstances!