Electrolux Nano Pro User manual

SERVICE MANUAL
PILOTLESS ELECTRONIC WATER HEATERS
1.- NO IGNITION No spark present. ...................................................................... 2
2.- NO IGNITION Water Heater sparking but the burner does not ignite. ............................ 3
3.- THE WATER FLOW IS VERY LOW ...................................................................... 3
4. CONTINUOUS SPARKING WHEN WATER HEATER IS IGNITED ...................................... 4
5.- SPARKING, BURNER IGNITES FOR A FEW SECONDS AND THEN SWITCHES OFF............... 4
6.- HARD IGNITION OF THE WATER HEATER THERE IS NO SOFT START.......................... 5
7.- WATER HEATER CONTINUES SPARKING WHEN TAP IS TURNED OFF............................. 5
8.- WATER HEATER SWITCHES OFF AFTER FEW MINUTES OF OPERATION ........................ 6
9.- WATER HEATER REMAINS IGNITED WHEN TAP IS CLOSED ...................................... 7
10.- FLAMES IN BURNER ARE YELLOW ..................................................................... 7
11.- THE BATTERY LIFE IS VERY SHORT .................................................................. 8
12.- USEFUL DATA............................................................................................. 9
13.- IGNITION SEQUENCE ..................................................................................10
14.- PHOTO GALLERY .........................................................................................11

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1.- NO IGNITION No spark present.
SYMPTOM POSSIBLE CAUSE OF FAILURE SOLUTION
No Spark
Check there is a battery in the Battery Box Insert a full battery in the Battery Box. Photo 1
Check that the battery is placed in the Battery Box in the correct
position Correct the position of the Battery. Photo 1.
The switch in the electronic circuit is in off position. Turn the switch on (inner position). Photo 4
The micro switch is not correctly connected or the connectors are
loosened. Check the status of the micro switch connection. Photo 7
Low water pressure. The main gas valve is not opening.
Check the water pressure.
Change the position of the temperature selector to Max.
temperature. ( Min Water Flow) Photo 4
The water inlet filter is dirty. The Water Flow is very low. Clean the water filter. Photo 3
The micro switch is not working correctly.
Disconnect the micro switch from the circuit. Shut off the gas inlet.
Short circuit the terminals in the electronic circuit. The circuit must
generate spark if circuit is O.K.
Adjust / Change the micro switch. In case it is necessary.
High ambient humidity. No sparking between electrodes. Dry the electrodes and clean them. Photo 5
The spark electrode wires have lost their insulation. Sparking is
taking place between the wires and earth or between the two
wires.
The electrode connector is defective.
Replace the electrode unit. Photo 5
The Ground connection of the electronic circuit is not correctly
connected. --> The Servo hasn’t any Voltage. Tighten the ground connection terminal. Photo 6
Wires not well connected to electronic circuit. Check the wiring installation.
TTB switch in Draught diverter is tripped Check that TTB is not Tripped (Tripped means contact opened).
Water valve diaphragm broken.
Communication channel between chambers obstructed.
Disassemble Water Valve. Change the diaphragm.
Clean the communication channel. Photo 8.
All models
Venturi obstructed. Check and change venturi. Photo 9.

3 of 15
SYMPTOM POSSIBLE CAUSE OF FAILURE SOLUTION
No Spark
Water valve O-rings are blocked. Disassemble Water Valve. Work the water pin manually to unblock
them / Change the top cover of the water valve. Photo 10.
All models
Main gas valve seal is blocked. Work the gas pin manually to unblock the O-ring. Photo 11.
Change Gas valve.
2.- NO IGNITION Water Heater sparking but the burner does not ignite.
SYMPTOM POSSIBLE CAUSE OF FAILURE SOLUTION
Battery Voltage very low. Sparkling is very at low frequency and
sounds very weak. Replace Battery. Use Alkaline battery. Photo 1
Battery is not correctly inserted in the Battery box. Check position of the Battery. Photo 1
No gas.
Low gas pressure. Open gas valve. / Check gas pressure.
Main Gas Valve is not opened. Microswitch needs adjustment Adjust Microswitch. Must be activated only with main valve opened
The spark is not generated in the sparking electrode. Check humidity on electrodes. Photo 5.
Check position of electrodes or whether they are deformed.
There is no voltage in Servo valve terminal.
Check the Electronic circuit earth connection. Photo 6.
Check the wiring.
Change the Electronic circuit.
It sparks but
the burner does
not ignite
In case there is voltage in servo terminal. Change the gas valve. The servo is incorporated in the gas valve.
3.- THE WATER FLOW IS VERY LOW
SYMPTOM POSSIBLE CAUSE OF FAILURE SOLUTION
Water pressure is too low. Change the position of the water selector to MAX.. Photo 4
The water filter is dirty. Clean the water filter. Change the water filter. Photo 3.
The water flow is
very SMALL and the
water is coming out
VERY HOT. The heat exchanger in combustion chamber is obstructed. Clean the heat exchanger.
Change the combustion chamber.

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4. CONTINUOUS SPARKING WHEN WATER HEATER IS IGNITED
SYMPTOM POSSIBLE CAUSE OF FAILURE SOLUTION
Continuous sparking
and burner is ignited
The electronic circuit is not working correctly. Replace the Electronic circuit. Photo 2.
5.- SPARKING, BURNER IGNITES FOR A FEW SECONDS AND THEN SWITCHES OFF
SYMPTOM POSSIBLE CAUSE OF FAILURE SOLUTION
Air in gas pipes. Purge air from gas pipes.
Low gas pressure. Check gas pressure.
The electrode unit has come loose.
The electrode flame sensor is out of position.
The electrode flame sensor is deformed. See manual:
electrodes life….
The electrode connector is not properly connected.
Tighten the electrode fixing screw. Photo 5.
Change the electrodes.
Check the connection of this connector. Photo 7 & Photo 13.
The electronic circuit Ground terminal is not properly
connected. Tighten the Ground connection terminal. Photo 6.
Electronic circuit is defective. No Voltage in Servo terminal Change the electronic circuit.
The burner switches
off after remaining
on for a few
seconds
Servo Valve is defective Check Voltage in Servo terminal. Photo 17.

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6.- HARD IGNITION OF THE WATER HEATER THERE IS NO SOFT START
SYMPTOM POSSIBLE CAUSE OF FAILURE SOLUTION
Battery Voltage very low. Sparkling is very at low
frequency and sounds very weak. Replace Battery. Use Alkaline battery. Photo 1.
The electrodes are not correctly fixed to the manifold.
They are too high referred to the burner blades. Fix the electrodes correctly using the fixing screw. Photo 5.
There is a gas accumulation in the combustion chamber Electronic circuit defective, there is servo voltage with no Flame.
Check Servo valve closes when no energized.
There is air in the gas supply line. Drain the gas circuit.
Excessive gas pressure. Check the gas inlet pressure Photo 17. Nominal gas Pressure 13 mbar.
Check / adjust the gas pressure in the burner Photo 12.
The Ground terminal of the electronic circuit is not
properly connected. Tighten the Ground connection terminal. Photo 6.
Defective wiring of electronic circuit. Check the wiring and change it if necessary.
The servo is not working correctly. No soft start function Change the gas valve. The Servo is integrated in the gas valve. Photo 17.
The burner ignites
WITHOUT SOFT
START
The nozzles are not well fitted. The change of gas type has not been made correctly.
7.- WATER HEATER CONTINUES SPARKING WHEN TAP IS TURNED OFF
SYMPTOM POSSIBLE CAUSE OF FAILURE SOLUTION
Micro switch not properly adjusted. Check micro switch adjustment. Microswitch adjustment screw Photo 17.
The micro switch has broken (The contacts are stuck).
Sparkling only occurs for 5 seconds. Check function of micro switch Change the micro switch Photo 17 –
The water heater is
sparking when the
tap is turned off.
The Electronic circuit is faulty. Change the Electronic circuit Photo 2.

6 of 15
8.- WATER HEATER SWITCHES OFF AFTER FEW MINUTES OF OPERATION
SYMPTOM POSSIBLE CAUSE OF FAILURE SOLUTION
Low Battery Voltage Replace the Battery. Photo1.
Gas pressure/flow insufficient. Check burner gas pressure. Photo 18.
Drop in water pressure during functioning of the water
heater. Check the water pressure.
The TTB sensor is Tripped. Smoke exhaust defective Check the status of the TTB sensor. Photo 16.
The water filter is dirty. Check the status of the water filter. Change or clean it if necessary.
Photo 3.
Membrane in water valve broken. Change the membrane. Photo 8.
Venturi dirty / obstructed. Remove and check the venturi. Change it if necessary. Photo 9.
The electrode unit has become loose. Tighten the electrode fixing screw. Photo 5.
The electrode connector is not properly connected. Check the connection of this connector. Photo 2 and 13.
The Ground terminal of the electronic circuit is not
correctly connected. Tighten the Ground connection terminal. Photo 6.
Electronic circuit is defective. Change the control circuit.
Water heater
switches off after
few minutes of
operation
The Servo is defective. Test Voltage in Servo. Change the gas valve in case there is no
function. The servo is integrated in the gas valve. Photo 17 and 18

7 of 15
9.- WATER HEATER REMAINS IGNITED WHEN TAP IS CLOSED
This is a DANGEROUS situation because the Pressure and Temperature in the combustion chamber will increase very fast,
DISCONNECT THE GAS SUPPLY TO THE WATER HEATER.
PERMANENT DAMAGES AND DEFORMATIONS IN WATER VALVE AND COPPER PIPES.
SYMPTOM POSSIBLE CAUSE OF FAILURE SOLUTION
Water Valve shaft blocked. Check the water valve/change the top cover of the water valve. Photo
10.
Communication channel between chambers obstructed. Clean the communication channel. Photo 8
Water leak from upper cover – rust in water neck
blocking up the pins. Change the water and gas valves.
Main regulator of open selector in water valve is
blocked..
Check the regulator move freely in their housing. Photo 9
Change the Water Valve if necessary
Venturi obstructed. Check / change venturi. Photo 9
The water heater
remains ignited
when the tap is
turned off.
Gas shaft blocked. Check the gas pin O-ring / change the O-ring Photo 11.
10.- FLAMES IN BURNER ARE YELLOW
SYMPTOM POSSIBLE CAUSE OF FAILURE SOLUTION
Excessive gas pressure. Check gas pressure at the water heater inlet and at the burner.
Adjust Burner Pressure. Photo 12, 17 and 18.
Dirt in burner. Clean the burner.
Unsuitable nozzles.
The gas change has not been made correctly. Replace the nozzles.
Burner flames are
yellow
Burner incorrectly assembled or misaligned. Adjust burner or align it.

8 of 15
11.- THE BATTERY LIFE IS VERY SHORT
SYMPTOM POSSIBLE CAUSE OF FAILURE SOLUTION
Some of the wirings is damaged and is in contact with
a metallic part of the water Heater
Review status of wirings.
Change electrical installation if necessary
The servo valve current consumption is very high Servo valve defective. Change gas valve.
The servo valve is always opened. Electronic circuit defective / Replace Electronic circuit. Photo 2
Electronic circuit defective. Replace electronic circuit. Photo 2.
The Battery life is
very short
A Saline Battery has been used. Battery must be Alkaline.

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12.- USEFUL DATA
CONNECTION DIMENSIONS
GAS 3/4"
WATER INLET 3/8"
WATER OUTLET 1/2"
EXHAUST
Chimney Diameter 112 mm internal
DIMENSIONS
ABCDEFGHI J K L
310 578 228 240 112 102 69,4 21 50 133,8 210 115,6
GAS INLET PRESSURE
NATURAL G20 13mbar
BURNER PRESSURE
10,8 mbar
WATER PRESURE
Maximum 13 bar
Minimum OS 0,25 bar
Minimum CS 0,15 bar

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13.- IGNITION SEQUENCE
Open
the
Tap
Water Valve
Pin goes Up
Main Gas Valve
Opens
GAS TO
BURNER
Microswitch
contacts
close
BURNER
IGNITED
Servo valve
OPENS
Spark in
Electrodes.
Control
circuit
Water Heater
Working System
Tripped
Main Gas Valve closed
Microswitch opens
Servo valve Closed
YES NO
5 seg.
timer
Flame
detection
t< 5seg
Flame LED
ON
YES
NO
Is the Tap
opened?
Water Heater in
Stand by. To Reset the system;
Close and re open the
Tap

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14.- PHOTO GALLERY
2
PC 102 Ignition
Circuit
LED Burner ON
ON/OFF Switch
P
OSI
T
IVE
POLARITY
INDICATED IN
CASE COVER
1
Electrodes
connector
3
Water filter
location in the
water valve
4
Water Temperature
selector
ON OFF Switch
LED Burner ON
Gas Power selector

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7
Microswitch
Connector
Electrode
Connector
Ground
Connection
Electrode
Connector
6
5
Electrode
Assembly
Clean
Electrodes!!
Fixing Screw for
electrodes
8
Water Valve
Membrane
Communication
Channel

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12
Screws for power
adjustment
Manual Drive
Water Valve Pin
10
9 Ventury
Main Regulator
in Water Valve
Main Regulator
housing in Water
Valve Body
Drainage
Screw
11 Manual drive Pin
Gas Valve

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16
TTB Connections
TTB Sensor
14
Water Inlet
Water
Outlet
Drain Screw
Ventury
Water
Selector
13
Electrode
Connector
15
Water Pin
O ring and
gaskets
D
i
sc
Water Valve
Upper cover

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18
Burner Pressure
checking point
17
Servo valve
Terminal
Gas inlet Pressure
checking point
Micro switch
adjustment screw