Immergas EOLO STAR 24 3 E Guide

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STNS3E ed 09/08 NIKE Star 24 3 E
Technical documentation Technical documentation
NIKE Star 24 3 E
Small wall-mounted open chamber, conventional
ue instant boiler.
NIKE Star 24 3 E
NIKE Star 24 3 E is a wall-mounted, open combustion cham-
ber, conventional ue generator for the heating and production
of domestic hot water.
e boiler distinguishes itself for its extremely small dimensions
H=751 mm, L=440 mm, D=240 mm) and useful heat output
of 23.6 kW (20,296 kcal/h).
Adjustment and control of the appliance (burner ignition,
temperature adjustment, ame modulation and diagnostics), are
entrusted to an electronic P.C.B. with microprocessor that by
means of a digital interface complete with display and buttons,
General features.
allows the visualisation and adjustment of the functioning
parameters.
e hydraulic circuit is equipped with a bithermal water-gas
copper heat exchanger for the production of hot water for
central heating and domestic hot water use, an automatic
by-pass of the system and a ow switch for the cut-o of DW
withdrawal.
e appliance has IPX4D electrical insulation rating: this
means that the boiler is protected against jets of water and
high humidity levels.
Key:
G - Gas supply
AC - Domestic hot water outlet
AF - Domestic cold water inlet
R - System return
M - System ow
V - Power supply connection
Main dimensions and connections.
Height (mm) Width (mm) Depth (mm)
751 440 240
CONNECTIONS
GAS DOMESTIC
HOT WATER SYSTEM
GAC AF R M
3/4” 1/2” 1/2” 3/4” 3/4”

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Key:
1 - System lling valve
2 - Domestic hot water probe
3 - Gas valve
4 - Domestic hot water ow switch
5 - Combustion chamber
6 - Flue hood
7 - Flue safety thermostat
8 - Safety thermostat
9 - Flow probe
10 - System expansion vessel
Main components.
11 - Air vent valve
12 - System pressure switch
13 - Boiler pump
14 - Manifold
15 - 3 bar safety valve
16 - System draining valve
17 - Rapid heat exchanger
18 - Ignition and detection electrodes
19 - Burner

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STNS3E ed 09/08 NIKE Star 24 3 E
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Key:
1 - Reset button
2 - Stand-by/summer/winter button
3 - Button (+) to increase
the domestic hot water temperature
4 - Button (-) to reduce
the domestic hot water temperature
5 - Button(+) to increase the system water temperature
6 - Button (-) to reduce the system water temperature
7 - Boiler manometer
8 - Domestic hot water functioning
Control panel.
9 - Temperatures and error code display
10 - Unit of measurement
11 - Central heating functioning
12 - Winter
13 - Summer
14 - Power distributed
15 - Flame presence

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e central heating circuit, with relative control and safety
devices, is started every time there is a central heating
request.
Operation.
e heat contained in the combustion products is absorbed
by the copper blades of the water-air heat exchanger (7) which
then gives the heat up to the water made to circulate inside
the boiler pump.
e hot water is introduced directly into the central heating
system through ow (M) and return (R) pipes.
Key:
1 - Domestic hot water probe
2 - Domestic hot water ow switch
3 - Gas valve
4 - Flow limiter
5 - System draining valve
6 - Burner
7 - Rapid heat exchanger
8 - Flue hood
9 - Flue safety thermostat
10 - System expansion vessel
11 - Flow probe
12 - Safety thermostat
13 - Air vent valve
14 - Boiler pump
15 - System pressure switch
16 - Automatic by-pass
17 - 3 bar safety valve
18 - System lling valve
G - Gas supply
AC - Domestic hot water outlet
AF - Domestic cold water inlet
R - System return
M - System ow
Hydraulic circuit.
Primary circuit (Boiler Circuit).
e hot water used for central heating and domestic hot
water is produced thanks to two distinct circuits that are
aected according to necessity.

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STNS3E ed 09/08 NIKE Star 24 3 E
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2
3
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1
4
Boiler pump (1).
Operates on the primary circuit return. It is part of the pump
body unit realised in composite material.
ere is a seat where the automatic air vent valve (2) is housed
with O-ring sealing.
To remove the air vent valve from the pump body, turn the
valve by a quarter turn in an anti-clockwise direction.
Head ow rate graphics.
In central heating mode the generator guarantees available head
to the system depending on the ow rate, which s represented
by the following graphics that show the characteristic curve.
Head (m H2O)
A = Head available to the plant.
Portata (l/h)
Head (kPa)
A
Primary heat exchanger.
It is a bithermal water-air blade-type heat exchanger with
copper pipes and ns (N° 72 ns) that produce hot water for
central heating and domestic hot water.
It therefore operates directly in both circuits (DHW or CH)
to which it is connected directly by push tting pipes (2) with
O-ring sealing and blocked using relevant clips (3).
e 6 oval pipes of which it is formed and through which
CH circuit water runs, contain just as many "cross-wise"
pipes that are aected by the direct passage of the DHW (see
gure below).
ese pipes are hydraulically connected in parallel three by
three onto the CH circuit and in series in the DHW circuit.
At the heat exchanger outlet (central heating ow) nd the
NTC ow probe (1) and the over-heating safety thermostat
(4).
Domestic
cold water
inlet Domestic
hot water
outlet
Domestic
hot water
outlet
System
ow
Return
system
Heat exchanger pipe section
System central
heating circuit DHW circuit
1
2
Flow rate (l/h)

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Safety devices and controls.
System automatic by-pass (3).
Guarantees circulation in the CH circuit also when the high
resistance of the system does not allow it.
It operates between the ow and the return of the CH circuit
and is inserted inside the by-pass tting (4) that connects the
pump unit (2) to the ow.
System ling unit (7).
It is a cock positioned between the boiler circuit and the dome-
stic cold water inlet that allows to pressurise the CH system.
e lling unit is connected to the DHW ow switch (6) by
a threaded tting and is connected to the pump unit (2) by
O-ring gaskets.
System pressure switch (5).
Detects the pressure inside the primary circuit.
Its seat is on the pump body (2) and is coupled to a micro
switch that prevents functioning of the burner when the pres-
sure detected is below 0.3 bar.
Prevents overheating of the primary heat exchanger.
Automatic air vent valve (1).
Allows the automatic expulsion of the gaseous substances that
may be present in the boiler circuit.
It is mounted on the pump directly on the body (2).
3 bar safety valve (5).
Prevents the safety pressure in the primary circuit from being
exceeded (3 bar).
It is engaged into the front part of the pump body (2) and is
xed using a clip.
Its intervention causes water to escape from the boiler re-
turn.
System expansion vessel (8).
It compensates the volume variation consequent to heating
the water, thus limiting the pressure variations.
It has a capacity of 6 litres (useful 4.2 litres) and a factory/set
pressure of 1.0 bar.
It is positioned on the right side of the boiler at the side of
the sealed chamber and is connected to the pump body (2) by
means of a copper pipe.
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2
3
5
6
7
2
5

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Secondary circuit (Domestic Hot water Circuit).
Operation.
A DHW withdrawal leads to the passage of cold water inside
the ow switch (4) and the consequent closure of the electric
contact coupled to it (see electric circuit).
Following this, the adjustment circuit starts the DHW priority
functioning mode, which leads to burner ignition (3) and,
when a CH request is in progress, switch o of the boiler
pump.
In this way, the heat contained in the combustion products is
absorbed by the copper blades of the bithermal heat exchanger
(2) is given up to the water in the central heating circuit which,
then transmits it to the domestic cold water that ows through
the “cross-wise” DHW pipes (1).
Domestic hot water ow switch.
With respect to a withdrawal of DHW with a ow rate of at
least 1.7 l/min and a dynamic pressure of 0.3 bar, the ow
switch (2) enables the boiler functioning in DHW mode.
is takes place by means of a magnet which, lifting when
it is hit by the ow of domestic cold water, approaches an
electric contact (reed relay) and causes shifting due to the
magnetic eect.
e closure of the contact, which is positioned out of the pipe
where the water passes, allows the integrated P.C.B. to start
the priority DHW functioning mode.
It is made up from two parts (one in brass and one in plastic)
that are coupled and blocked by a pin.
A G1/4" thread is present on the body to which the system
lling unit is connected (3).
A 7.1 l/min ow limiter is inserted at the outlet of the ow
switch (1) (at 2 bar).
Bithermal heat exchanger
(see central heating circuit).
N.B.: to preserve the duration and eciency of the heat exchanger
it is recommended to install the “polyphosphate dispenser” kit in
the presence of water whose characteristics can give rise to scale
deposits (for example, the kit is recommended when water hardness
is higher than 25 French degrees).
1
2
3
Domestic cold
water inlet

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e circuit is composed of an atmospheric burner and a mo-
dulating gas valve, which respectively allow the combustion
of the gas and the adjustment of its ow rate.
Operating.
e electric power supply of the main coils (3) causes the
opening of both internal shutters of the valve, thus allowing
the passage of gas towards the burner. e outlet ow rate/
pressure is then adjusted by acting on the gas valve stabiliser
by means of the modulation coil (1).
e fuel is injected, by means of the burner nozzles (6), into
the horizontal Venturi pipes (ramps). Here, an optimal air-gas
mixture is obtained that is ignited by the spark of the ignition
electrode (4).
Modulating gas valve (VK 4105 M).
e gas valve is equipped with two main coils (3) and a mo-
dulation coil (1) controlled by the integrated P.C.B.
e maximum and minimum outlet pressure values are cali-
brated on the valve (see gas adjustments).
Main electric coils (3).
ey are two ON-OFF coils that are powered (230 V AC) by
the integrated P.C.B. when burner ignition is necessary.
ey are connected in series and powered at network voltage
rectied by means of a diodes jumper (U1) positioned inside
connector (2) (see wiring diagram).
Gas circuit.
Modulation coil (1).
It is a low voltage coil that is controlled by the integrated
P.C.B.
It acts on the gas valve stabiliser and allows the variation of
the outlet pressure proportionally to the direct current that
passes through it.
Modulating gas valve (SIT 845).
e gas valve is equipped with two main coils (3) and a mo-
dulation coil (1) controlled by the integrated P.C.B.
e maximum and minimum outlet pressure values are cali-
brated on the valve (see gas adjustments).
Main electric coils (3).
ey are two ON-OFF coils that are powered (230 V AC) by
the integrated P.C.B. when burner ignition is necessary.
ey are connected electrically in parallel and powered from
the mains voltage via a relevant connector (2).
Modulation coil (1).
It is a low voltage coil that is controlled by the integrated.
COIL POWER SUPPLY RESISTANCE
EV1 + EV2 230 V AC EV1 = 2,85 kΩ
EV2 = 1,35 kΩ
Modulation coil
(Blue)
250mA DC (G20)
320mA DC (L.P.G.) 28 Ω
Reference values with boiler at maximum power
1
3
2
EV1
EV2 EV1
+
EV2 =
230V
Connector viewed
from the gas valve
Modulation
Coil



Modulation
Coil
Connector viewed
from the gas valve
EV1
EV2
Common

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Height to respect:
H min = 2,5 mm
H max = 4 mm
Nominal position on the
third pair of slots
It acts on the gas valve stabiliser and allows the variation of
the outlet pressure proportionally to the direct current that
passes through it.
Burner.
e burner is made up from 11 horizontal Venturi pipes (5)
into which the gas is injected by just as many nozzles (6)
mounted on the relevant collector (7), whose diameter varies
according to the type of gas used (see technical data).
Ignition takes place thanks to an integrated P.C.B. that controls
the ignition and detection electrode (4).
Ignition and detection electrode (4).
In the ignition mode, it is controlled by the integrated P.C.B.
that causes an electric spark between its ends and the surface of
the burner on the contact of which the air-gas mix ignites.
Once the burner is on, it detects ame presence on the burner
allowing the integrated P.C.B. to conclude the ignition cycle
and to vary the gas pressure as required.
It is positioned on the front of the burner in correspondence
with the central ramp.
COIL POWER SUPPLY RESISTANCE
EV1 230 V AC 6,25 kΩ
EV2 230 V AC 860 Ω
Modulation coil 250mA DC (G20)
320mA DC (L.P.G.) 22 Ω
Reference values with boiler at maximum power
Note: for correct ignition and detection of the boiler always
respect the quotes stated in the gure below.
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