Immergas NIKE Mini Export User manual

NIKE Mini Export
Compact wall-hung instantaneous
conventional flue boilers
NIKE Mini Export

Technical documentation Technical documentation
STNME ed 07/03 1 NIKE MINI
NIKE Mini
Conventional flue wall-hung boiler
with instantaneous production of
D.H.W. and compact dimensions
NIKE Mini
- GENERAL FEATURES
NIKE MINI is a wall-hung conventional flue for central heating and the production of domestic hot
water that stands out for its compact dimensions (773 x 450 x 250).
The boiler features a microprocessor-controlled electronic board that electronically controls burner
ignition, central heating and d.h.w. temperature and flame modulation.
The unit has a working heat output of 20.000 kcal/h (23,3 kW) and features a standard antifreeze safety
device that ensures operation with temperatures as low as - 5°C.
The hydraulic circuit features a copper water-gas exchanger, a 3-way hydraulic valve and a
STAINLESS-STEEL plate exchanger for the instantaneous production of domestic hot water.
- MAIN DIMENSIONS AND CONNECTIONS
DIMENSIONS (mm)
HEIGHT WIDTH DEPTH
773 450 250
CONNECTIONS
GAS D.H.W. SYSTEM
G U E R M
1/2 “ 1/2 “ 1/2 “ 3/4 “ 3/4 “
V - power supply
G - gas supply
U – domestic hot water outlet
E – domestic hot water inlet
R - system return
M - system flow

Technical documentation Technical documentation
STNME ed 07/03 2 NIKE MINI
MAIN COMPONENT PARTS
(until serial number 2243650)
1 - Adjustment and limit NTC sensor
2 - 3-way hydraulic valve
3 - Gas valve
4 - System filling valve
5 - Flue safety thermostat
6 - Flue hood
7 - Exchanger overheat safety (115 ºC)
8 - Expansion vessel
9 - Combustion chamber
10- Automatic air vent valve
11- Circulating pump
12- D.h.w. exchanger
13- 3-bar safety valve
14- System drain valve
15- Primary heat exchanger
16- Ignition and detection electrodes
17- Burner
18- Control panel
19- Overheat safety thermostat (100 ºC)

Technical documentation Technical documentation
STNME ed 07/03 3 NIKE MINI
MAIN COMPONENT PARTS
(from serial number 2243651)
1 - 3-way hydraulic valve
2 - Gas valve
3 - System filling valve
4 - Flue safety thermostat
5 - Flue hood
6 - Overheat safety thermostat (105 ºC)
7 - Adjustment and limit NTC sensor
8 - Expansion vessel
9 - Combustion chamber
10- Automatic air vent valve
11- Circulating pump
12- D.h.w. exchanger
13- 3-bar safety valve
14- System drain valve
15- Primary heat exchanger
16- Ignition and detection electrodes
17- Burner
18- Control panel
CONTROL PANEL
1 - Boiler thermo-pressure gauge
2 - Flame presence yellow indicator lamp
3 - Boiler block led indicator lamp
4 - 0/SUMMER/WINTER/RESET switch
5 - D.h.w. temperature selector
6 - Central heating temperature selector
7 - Programmer clock hole plate

Technical documentation Technical documentation
STNME ed 07/03 4 NIKE MINI
HYDRAULIC CIRCUIT
(until serial number 2243650)
(from serial number 2243651)
1 - System filling valve
2 - Hot water flow switch micro.
3 - Gas valve
4 - 3-way hydraulic valve
5 - Adjustment and limit NTC sensor
6 - D.h.w exchanger
7 - Burner
8 - Primary heat exchanger
9 - Stack safety thermostat
10 - Flue hood
11 - Overheat safety thermostat (TS1)
12 - Expansion vessel
13 - Automatic air vent
14 - Circulating pump
15 - Flow limiting device
16 - System drain valve
17 - 3-bar safety valve
18 - Overheat safety thermostat (TS2)
(fitted until serial number 2243650)
G - Gas supply
U - Hot water outlet
E - Hot water inlet
R - System return
M - System delivery
.

Technical documentation Technical documentation
STNME ed 07/03 5 NIKE MINI
The hot water used for central heating and the d.h.w. supply is produced by a primary circuit and a
secondary circuit (domestic hot water), which operate according to need.
PRIMARY CIRCUIT (BOILER CIRCUIT)
The primary circuit with relevant control and safety devices is started every time there is a
central heating, domestic hot water request or antifreeze request.
- OPERATION
The heat contained in the flues produced by combustion is absorbed by the copper blades of the
water-gas exchanger (8) which, in turn, transfers this to the water that circulates inside by means
of the boiler pump (16).
The hot water then directly enters the heating system through the delivery pipe (M) and return
pipe (R).
- CIRCULATOR
This operates on the primary circuit return and
is physically located on the brass return
manifold unit.
It is connected to the monobloc and primary
exchanger by means of pipes with threaded
fittings.
The casing features a threaded fitting onto
which the automatic release valve (1) is
fastened.
- HEAD FLOW GRAPH
The curve representing the system flow and
head ratio depends on the speed of pump
operation.
The curves shown on the graph alongside
refer to:
- A = Circulator at top speed
- B = Circulator at second speed
- C = Circulator at top speed with by-pass
(optional) on
- D = Circulator at second speed with
by-pass (optional) on

Technical documentation Technical documentation
STNME ed 07/03 6 NIKE MINI
- PRIMARY HEAT EXCHANGER
This is a blade type water-gas exchanger consisting of four pipes connected together in series.
This is connected to pump delivery (return) and to primary circuit delivery (delivery) by means
of coupling pipes (3) featuring O.R. seals (5) secured by means of special forks (4).
(until serial number2243650)
At the outlet.(delivery) is the overheating safety
thermostat at 115 ºC (2).
The outlet pipe features the 100 °C safety
thermostat (6) and the NTC delivery sensor (7).
(from serial number 2243651)
At the outlet.(delivery) are the overheating safety
thermostat at 105 ºC (2) and the NTC delivery
sensor (7).
On the outlet pipe is fitted anything.

Technical documentation Technical documentation
STNME ed 07/03 7 NIKE MINI
- SAFETY DEVICES AND CONTROLS
System bypass (1) (optional)
Ensures circulation of water in the primary circuit
(between delivery and return) even when the high
resistance of the system does not permit.
It is fitted between the system delivery and return
connection pipes.
System filling valve
This cock is located between the boiler circuit and
the cold d.h.w. inlet and permits pressurising the
heating system
The housing is obtained in the lower part of the
three-way valve body to which it is screwed up.
(see no. “13” 3-way valve ).
System drain valve (3)
This is a brass cap featuring a hose connector
fitted (screwed) on the bottom part of the return
manifold (2).
By loosening this, the water of the primary circuit
can be externally released.
3-bar safety valve (4)
Prevents safety pressure being exceeded in the
circuit (3 bar).
It is connected in the front part of the manifold (2)
to which it is fitted on the side by a socket screw.
Operation of this valve causes water to run out of
the return pipe.
Automatic air vent (6)
Allows automatic expulsion of any gaseous
substances in the boiler circuit.
It is fitted to the delivery pipe of the pump directly
to the body.
Expansion vessel (7)
This compensates for any changes in volume
caused by water heating and permits restricting
pressure changes.
It is positioned on the right of the boiler alongside
the sealed chamber and has a pre-load pressure of
0.8 bar and a capacity of 6 l.
It is connected to the return manifold (2) by means
of a copper pipe (5) with threaded fittings.

Technical documentation Technical documentation
STNME ed 07/03 8 NIKE MINI
HYDRAULIC CIRCUIT
SECONDARY CIRCUIT (DOMESTIC HOT WATER CIRCUIT)
- OPERATION
A d.h.w. request causes cold water to flow through the 3-way valve (1) and its subsequent movement to
operating position (see hydraulic 3-way valve operation).
This causes the delivery pipe (M) to close with simultaneous opening of the passage towards the d.h.w.
exchanger (2).
This way, circulation is prevented in the heating system, while this does occur in the plate exchanger,
inside which the d.h.w. cold water absorbs the heat contained in the primary circuit water (see d.h.w.
exchanger).
During this stage, the central heating function is disengaged and d.h.w. production has priority.
- DOMESTIC HOT WATER
EXCHANGER
This is a water-water exchanger consisting of 13
stainless-steel plates, one over the other, on the
surface of which the boiler circuit water and d.h.w.
cold water run in counter-current, and by means of
which heat exchange between the two liquids occurs.
It is fitted horizontally and is connected to the 3-way
valve (primary circuit delivery), to the hot water
outlet pipe and to the return pipe of the primary
circuit by means of threaded unions with flat seal
(1).
From serial number 1511772 for NIKE Mini and
from serial number 1507922 for EOLO Mini, the
hydraulic coupling to the 3-way valve (cold water
inlet) is of the coupling type with OR seal (2), while
previously it was obtained by means of a threaded
union with flat seal.

Technical documentation Technical documentation
STNME ed 07/03 9 NIKE MINI
- 3-WAY HYDRAULIC VALVE
Whenever a domestic hot water request is made, the 3-way valve has to deviate the flow of water
of the primary circuit from the central heating system to the plate exchanger.
It is therefore connected to both the primary circuit (primary circuit delivery, system delivery and
d.h.w. excha nger delivery) and to the d.h.w. circuit (cold water inlet, plate exchanger cold water
inlet).
The component part consists of a brass structure with inside an area where the transit (supply) of
d.h.w. is detected and another area where, as a result, deviation is made to the boiler circuit.
Inside are devices that carry out this function and which, if necessary, can be replaced using the
revision kit for three-way valves in which are fitted all the component parts subject to wear
(diaphragm, rods, OR, shutter, etc).
To perform this operation, the lid (6) will have to be removed and the two parts separated that
make up the valve body after loosening the socket-head retention screws (9).
The 3-way valve assembly also features the housings for the system filling stopcock (13) and the
8 l/min flow limiting device (8).

Technical documentation Technical documentation
STNME ed 07/03 10 NIKE MINI
Idle position (central heating)
The thrust exercised by the spring “1”
affects the diaphragm plate “4” and the
d.h.w. valve “3” fastened to rod “5”.
The valve “2” is thus kept up tight with
consequent closing of the passage
towards the d.h.w. exchanger and the
simultaneous opening towards the
system delivery pipe (M).
Following a central heating request,
pump operation causes circulation in
the system through the delivery pipe
(M) and return pipe (R).
Operating position (d.h.w.)
The flow of domestic hot water inside
the valve invests the d.h.w. valve which,
when idle, is tight up against the plate of
the perforated diaphragm “4”.
Upon transit of the water, the pressure
downstream of valve “3” is less than that
upstream (“venturi effect”).
With a flow of at least 1.5 l/min and a
dynamic water pressure of 0.3 bar, the
pressure difference between the two
points is such as to cause movement of
diaphragm “4”.
This permits pressing spring “1” and the
release of spring “11” with the
consequent movement of valve “2” and
rods “5” and “6”.
In this condition, the delivery pipe (M) is
closed while the passage towards the
plate exchanger is open.
At the same time, rod “7” positions (drops) at the point of contact of rods “5” and “6” causing the
electrical closing of the d.h.w. microswitch “8”.
At the end of the supply, the pressure difference upstream and downstream of the d.h.w. valve “3” is
cancelled out, allowing the valve to return to idle position.

Technical documentation Technical documentation
STNME ed 07/03 11 NIKE MINI
GAS CIRCUIT
The circuit consists of an atmospheric burner and a modulating type valve for gas combustion and
gas flow adjustment respectively.
- OPERATION
When the main coils (3) are energised, both inner valve shutters open, allowing the gas to flow
towards the burner.
The flow rate/outlet pressure is regulated by means of the gas valve stabiliser and the modulation
coil.
By means of the burner nozzles (7), the fuel is injected into the venturi pipes (ramps) inside which
the air-gas mix is obtained that is ignited by the spark from the ignition electrodes (5).
- MODULATING GAS VALVE
The gas valve (Honeywell VK 4105 or SIT 845) features two main coils and a third modulation coil
controlled by the adjustment board.
The maximum and minimum outlet pressure settings can be made on this valve (see gas
adjustments).
Main electrical coils (3)
Two coils of the ON-OFF type energised
(230V AC) by the board ignition circuit when
the burner has to be ignited.
In the case of the SIT 845 valve, the two coils
are electrically connected in parallel, while in
the case of the Honeywell VK 4105 valve,
these are connected in series and energised by
mains power rectified through a diode jumper
inside the connection connector (2).
Modulation coil (1)
This is a low-voltage coil controlled by the
modulation circuit of the adjustment board.
This controls the gas valve stabiliser and
permits changing the outlet pressure in a way
proportionate to the signal that runs through it.
SIT 845
Honeywell VK 4105

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STNME ed 07/03 12 NIKE MINI
- BURNER
From serial number 1618839 the burner consists of 12 horizontal venturi pipes (6) (ramps were
previously 11) in which the gas is injected by an equal number of nozzles (7) mounted on the special
collector (8).
Ignition occurs by means of the adjustment board which controls the ignition electrodes (5) and detection
electrode (4).
Ignition electrodes (5)
These is controlled by the ignition circuit of the
adjustment board which produces an electrical
charge that ignites the air-gas mix.
They are positioned on the front of the burner in
line with the centre ramp.
Detection electrode (4)
This is controlled by the adjustment board and
detects burner ignition.
It is positioned on the front of the burner on the
ramp alongside the ignition electrodes.

Technical documentation Technical documentation
STNME ed 07/03 13 EOLO MINI
GAS ADJUSTMENTS
Max and minimum gas pressure adjustments
can be made by means of the gas valve
respecting the values shown on the tables
relating to each boiler for the type of
corresponding gas.
After fitting a pressure gauge to the gas
valve outlet (see illustration alongside),
proceed as follows:
- VALVE VK 4105 M (with yellow protection cap)
Minimum pressure adjustment
- After interrupting power to the
modulation coil, turn screw “3” clockwise
to increase pressure to the burner and
anticlockwise to decrease the pressure.
Maximum pressure adjustment
(to be done after minimum pressure
adjustment)
- Sample the d.h.w after setting the
temperature switch on maximum.
Turn nut “4” clockwise to increase the
pressure and anticlockwise to decrease the
pressure.
1) Modulation coil 5) Yellow protection cap
2) Coil pin 6) Gas valve outlet press. point
3) Min. output setscrew 7) Vale inlet press. point
4) Max output setscrew 8) Air press. point
- VALVE SIT 845
Maximum pressure adjustment
- Sample the d.h.w. after setting the
temperature switch at maximum.
Turn nut “3” clockwise to increase the
burner pressure and anticlockwise to
decrease it.
Minimum pressure adjustment
(to be done after maximum pressure
adjustment)
- After interrupting power to the
modulation coil, turn screw “2”
clockwise to increase burner pressure
and anticlockwise to decrease it.
1) Modulation coil
2) Minimum output setscrew
3) Maximum output set nut
4) Gas valve outlet pressure point
5) Gas valve inlet pressure point
6) Protection cap

Technical documentation Technical documentation
STNME ed 07/03 14 NIKE MINI
- CHANGING TYPE OF GAS
Adaptation to a type of gas different to that for which the boiler is intended, can be done by using
the special kits (natural gas or LPG).
The changeover consists in replacing the burner nozzles and in moving to the modulation board of
the “NATURAL GAS- LPG” (JP1) jumper.
The minimum and maximum pressures are then set on the gas valve in the way described above.
Adjustment of the minimum and maximum output during the heating phase and of burner ignition
pressure (see table below) can be done by means of the respective trimmers mounted on the
modulation board (see modulation board operation).
Slow ignition values in mbar (mm H2O)
Natural gas LPG
Nike Mini 3 (30) 6 (60)

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STNME ed 07/03 15 NIKE MINI
ELECTRICAL CIRCUIT
E1/E2 - Ignition electrodes
E3 - Detection electrode
F - Fuse
IG - Main switch
JP1 - Gas selector
JP3 - Heating timer selector
LD1 - Flame presence yellow led
LD2 - Fault indicator red led
MOD - Modulation coil
MP - Circulating pump
NM - Delivery sensor
OP - Programmer clock (timer)
P1 - Room thermostat jumper
SS - Domestic hot water switch
TA - Room thermostat
TF - Flue safety device
TS1 - Overheating safety device
TS2 (*) - Exchanger overheating safety
(fitted until serial number 2243650)
VG - Gas valve
The electrical circuit of the NIKE MINI boiler is fully controlled by an electronic modulation board that
controls all the electrical devices on the machine.
Depending on the type of request and the state of the safety devices, the board ignites the burner and
regulates the temperature of the d.h.w and central heating.
Some of the control and safety devices operate at mains voltage and others at low voltage.
230 V AC CIRCUIT
SAFETY DEVICES AND CONTROLS
Detection electrode
(E3)
This detects ignition of the burner by whose flame it is invested.
It is connected to the ignition/detection circuit of the adjustment board.
Fuse This interrupts power to the circuit when power input is over 2 A.
It is fitted on the adjustment board.
Fuse
2 A 250 V
.
Exchanger overheat. safety
(TS2)
(fitted until serial number
2243650)
When safety temperature is exceeded (115 ºC) this interrupts power to
the main coils of the gas valve (VG).
It is located at the outlet of the heat exchanger.
Two-contact
clicson thermostat
.
Overheating safety
thermostat
(TS1)
When safety temperature is exceeded this interrupts power to the
main coils of the gas valve (VG).
Until the serial number 2243650 it was located on the delivery pipe and
was set at 100 ºC.
From serial number 2243651 it is located at the outlet of the heat
exchanger and is set at 105 ºC.
Two -contact
clicson thermostat

Technical documentation Technical documentation
STNME ed 07/03 16 NIKE MINI
LOADS
Circulating pump
(MP)
This is powered by the adjustment board whenever there is a demand for heating, domestic
hot water or antifreeze.
Permits circulation of water in the boiler circuit.
Gas valve (VG)
(main coils)
This is powered by the ignition circuit of the adjustment board when the burner has to be
ignited.
Permits flow of gas to the burner.
Ignition electrodes
(E1 - E2)
This is controlled by the ignition circuit of the adjustment board which provokes an electric
spark that ignites the air/gas mix.
Programmer clock
(OP)
(optional)
This clock operates a switch (see low-voltage circuit safety devices and controls) enabling
or disabling boiler operation during heating for the selected time intervals.
This is powered with main switch in position 0. SUMMER and WINTER.
LOW VOLTAGE CIRCUIT
SAFETY DEVICES AND CONTROLS
Depending on position, permits:
Main switch
(IG)
0
(SUMMER)
(WINTER)
RESET
-circuit not powered
-hot water operation
- hot water and heating operation
- resets after the no ignition or high temperature
safety device have been activated (the RESET
position operates at mains voltage, closing a
contact that acts on the ignition circuit)
3-position double
switch + reset
button
Delivery sensor
(NM)
This permits to the modulation board to determine the temperature of the
water supply of the primary circuit.
Any breakage will stop burner operation.
Until the serial number 2243650 it was positioned in immersion in a
sump located on the three way valve body.
From serial number 2243651 it is located at the outlet of the primary heat
exchanger .
NTC sensor
10 kohm 25 ºC
Domestic hot water switch
(SS)
Following sampling of hot water, this affects the adjustment board so the
boiler starts up during the hot water mode.
When idle this enables operation during the heating mode.
Double-contact
switch
Flue thermostat
(TF)
In the event of weak stack draught, this affects the adjustment board,
preventing boiler operation for 30 minutes.
It is located on the draught diverter
Double-contact
clicson thermostat
Programmer clock switch
(OP)
(optional)
Operates on adjustment board, enabling operation of the boiler during
heating at selected times.
If this is mounted singly, connection is made on terminals 6 and 9 of
connector M3 after removing pre-existing jumper P1.
When fitted together with an room thermostat (TA) it must be connected
to terminals 6 and 7 of connector M3 after removing the pre-existing
jumper P1.
Double-contact
switch

Technical documentation Technical documentation
STNME ed 07/03 17 NIKE MINI
Room thermostat (TA)
(external optional)
By means of the adjustment board, this enables operation of the boiler
during heating when room temperature is below that required.
If fitted singly, connection is made to terminals 6 and 9 of connector M3
after removing the pre-existing jumper P1.
If fitted together with clock (OP) it must be connected to
terminals 8 and 9 of connector M3 after removing jumper P1.
Double-contact
switch
LOADS
Modulation coil
(MOD)
This is powered by the modulation board with a variable signal.
Permits changing the pressure of the gas to the burner.

Technical documentation Technical documentation
STNME ed 07/03 18 NIKE MINI
ELECTRICAL CIRCUIT
HEATING PHASE
(*) the main coils of the gas valve run at mains voltage rectified by means of a diode jumper only on the
Honeywell VK 4105 gas valve (diode jumper fitted on the valve connection connector)
(**) the overheating thermostat TS2 equipped the boiler until the serial number2243650
Operation
When the main switch (IG) is in WINTER position, it powers the low-voltage circuit and enables
operation during heating.
When the room thermostat (TA) contact is closed, the adjustment circuit starts the circulator (MP)
by closing the PUMP RELAY contact.
If the temperature read by the NTC delivery sensor (NM) is below that set on the control panel by
means of the heating potentiometer, the board excites the REQUEST RELAY.
This way, the board ignition circuit is enabled (IGNITION SECTION) which first of all triggers the
ignition electrodes (E1 - E2) and then excites the V/G RELAY.
With the consensus of the overheating thermostats (TS1 and TS2), the closing of the contact of V/G
RELAY powers both main coils of gas valve (VG).
Burner ignition is detected by the ionisation electrode (E3).
NOTE: Every time the boiler shuts off after reaching the set temperature, the adjustment circuit
stops burner operation in heating phase for 180/30 seconds.