Ariston VLS Flat 50 User manual

Technical Manual
Storage Electric Water Heaters - VLS
Date of issue: 29
th
July 2011
Updating date: 10
th
November 2011 Version: v_2 1
Because of continuing product improvements, Ariston Thermo reserves the right to change specifications without prior notice.

2
Table of contents
1. General information
1.1 Main features by version
1.2 Differences among versions
1.3 Technical drawings
1.4 Product dimensions
1.5 Technical stickers
2. Components
2.1 Packaging content
2.2 Tanks
2.3 Heating elements
2.4 Mg anode
2.5 Power board, connections and probes
2.6 HMI
3. Working modes and additional functions
3.1 Main features by version
3.2 Programming
3.3 ECO
3.4 ECO PLUS
3.5 Anti bacteria
4. Troubleshooting and maintenance
4.1 Displayed faults
4.2 Malfunctioning
4.3 Routine maintenance

3
1. General information
1.1 Main features by version
VLS
The most common version: half size, double comfort.
Characterized by the “SHOWER READY” icon on the button HMI,
this appliance is able to ensure hot water for the first shower in
the fastest way, half time versus traditional water heater. The
ECO function, learning by end user habits, allows to save energy
consumption and money expenses … all in only 270 mm deep.
Available in: Italy, East Europe, Iberian Peninsula, Balkans, North
Africa.
VLS PREMIUM
The TOP version: fashion design and programmable comfort.
Characterized by the rotational LCD display on the soft touch
HMI and by the front panel available in seven different colors,
this appliance is able to ensure the same performance and
functioning modes of VLS.
Moreover the end user can program the desired temperature
and the time at which hot water has to be ready.
Available in: East Europe.

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1.2 Differences among versions
VLS VLS PREMIUM
Capacities
50 litres
yes
yes
80 litres
yes
yes
100 litres
yes
yes
Design
Button HMI
yes
no
Soft touch HMI
no
yes
Front panel
no
7 colours available
Electronic
control
Power board
yes
yes
HMI board
yes
with LCD display
Heating element
HE1 (1’500 W, 230 V)
yes
yes
HE2 (1’000 W, 230 V)
yes
yes
Protection
Mg anode (30
50 l)
n° 2 (22 x 110)
n° 2 (22 x 110)
Mg anode (80
100 l)
n° 2 (25,5 x 190)
n° 2
(25,5
x
190)
Safety valve
8 bar
8 bar
Power cable
ELCB
no (standard cable)
no (standard cable)
Functions
Anti
bacteria
disabled by default
disabled by default
ECO
yes
yes
ECO PLUS
no
yes
Programming
no
yes
Markets
Italy
yes
no
East Europe
yes
yes
Iberian Peninsula
yes
no
Turkey
yes
no
Balkans
yes
no
North Africa
yes
no

5
1.3 Technical drawings
VLS VLS PREMIUM
1.4 Product dimensions
All the dimensions are measured in mm.

6
1.5 Technical stic ers
Multi position installation sticker
The product may be installed either vertically or
horizontally.
Warning: In the horizontal installation, rotate the
appliance clockwise so that the water pipes are on
the left (cold inlet water pipe at the bottom).
Front panel assembly explanation sticker
The PREMIUM versions could be personalized with
seven different colours front panel. The sticker
explains how to do this assembly.

7
2. Components
2.1 Pac aging content
Into the packaging, the following items are included:
FLAT Water Heater version choosen (power cable is already installed);
Only in PREMIUM versions, basic front panel to be mounted;
Safety valve (8 bar) to be installed on cold water inlet pipe (note: this component must be replaced
with a device in compliance with the EN 1487:2002, if this standard is mandatory in your Country);
Instruction manual.
2.2 Tan s
Tanks tailored design and serie connection between
them in order to reach the highest level of heat
stratification and the lowest depth size.
Same tanks flange for all the range: 5 bolts.
Same tanks diameter for all the range: 220 mm.
Different length by capacity.
Spare parts of these items are not available!
2.3 Heating elements
HE1 HE2
All the range is equipped with two heating
elements: the HE1 (red coloured), closer to the hot
water outlet pipe, is used to ensure hot water for
the first shower in the fastest way while the HE2
(blue coloured), closer to the cold water inlet pipe,
is used to maximize the comfort.
2.4 Mg anode
The Mg anode prevents corrosion of the tank and
the heating element.
Each tank is equipped with a specific anode
according to its capacity.

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2.5 Power board, connections and probes
main power board (PCB)
power cable (PCB HE1: red; PCB HE2: blue)
HE1 probe with cable (width = 8 mm)
HE2 probe with connector (width = 6,5 mm)
HE2 probe cable
Sensor Test Table (ohmic resistance values as a function of temperature)
T [ C]
R [kΩ]
T [ C]
R [kΩ]
T [ C]
R [kΩ]
T [ C]
R [kΩ]
T [ C]
R [kΩ]
T [ C]
R [kΩ]
40
195,7
10
42,5
20
12,1
50
4,2
80
1,7
110
0,8
35
148,2
5
33,9
25
10,0
55
3,5
85
1,5
115
0,7
30
113,3
0
27,2
30
8,3
60
3,0
90
1,3
120
0,6
25
87,6
5
22,0
35
6,9
65
2,6
95
1,1
125
0,5
20
68,2
10
17,9
40
5,8
70
2,2
100
1,0
15
53,6
15
14,7
45
4,9
75
1,9
105
0,9

9
If the PCB has to be replaced, it’s mandatory to set the jumpers present on the geniune spare part as a
function of the product capacity, following logical schemes below:
FLAT 50 litres
FLAT 80 litres
FLAT 100 litres
2.6 HMI
VLS
Buttons: ON/OFF, “ECO”, +/
Icons: “WAVES” (40 °C, 50 °C, 60 °C, 70 °C, 80 °C),
“SHOWER READY”
VLS PREMIUM
LCD display
“SET” knob
Buttons: ON/OFF, “MODE”, “ECO”
Icons: “WAVES”

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3. Working modes and additional functions
3.1 Main features by version
Press the ON/OFF button to switch on/off the appliance.
VLS
Working
During the heating phase, the
“WAVES” icon
corresponding to the
temperature reached by the water so far remain light in a fixed manner; all
subsequent “WAVES” icons (up to the set temperature) flash progressively.
Whatever the temperature set by the user, the “SHOWER READY” icon lights
up when there is sufficient hot water for at least one shower (40 litres of
water mixed at 40 °C).
How to change
the hot water set point
Press +/
buttons in order to increase/decrease the set
point (40 °C
80 °C):
the select set point value is displayed by fixed light waves and temperature.
Default settings
Hot water set
point = 70 °C
Anti bacteria function deactivated
ECO function deactivated
VLS PREMIUM
Working
During the heating phase, the
“WAVES” icons
on display side are switched on
and the temperature reached by the water so far is shown on the LCD display.
Whatever the temperature set by the user, the “shower ready” symbol is
shown on the LCD display when there is sufficient hot water for at least one
shower (40 litres of water mixed at 40 °C).
How to change
the hot water set point
(MANUAL mode)
Turn the “SET” knob clockwise/anticlockwise
in order to increase/decrease
the set point (40 °C 80 °C): the select set point value is shown flashing on
the LCD display; to confirm the displayed value, press the “SET” knob.
Default settings
Hot water set
point = 70 °C
Anti bacteria function deactivated
ECO function deactivated
In any setting procedure (except for the local time), if the user does not perform any actions for 5 seconds,
the last settings are stored in the appliance memory. If the product is disconnected by the power mains for
a long period, all the settings are stored into the appliance memory (except for the local time).
3.2 Programming
Only for PREMIUM versions, Programming modes are alternative to the MANUAL mode.
The functions “Programming 1” (“P1” symbol lit on the LCD display), “Programming ” (“P ” symbol lit on
the LCD display) and “Programming 1 and ” (“P1” and “P ” symbols lit on the LCD display) can be used to
programme 1 or time bands for the day on which hot water is required.
VLS PREMIUM
How to change
the working mode
Press the
“MODE
” button
to select
a different operating mode (the mode is
indicated by the flashing of the corresponding symbol/symbols on the display).
Functions are selected on a cyclic basis, in the following order: “P1”  “P2” 
“P1 and P2”  “MANUAL”  “P1”  etc.

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How to set/adjust
the local time
T
he first time the
product is switched on, it
automatically prompt
s
you to set the
correct time; on subsequent occasions you need to press and hold the "SET"
knob for 3 seconds.
Adjust the current hour setting by turning the “SET” knob, then confirm the value
by pressing the knob. Repeat the procedure to set the minute value.
How to change
the hot water set point
and time bands
Press
the “MODE” button until the symbols
relating to the desir
ed programme
begin flashing.
At this point turn the “SET” knob to select the time band in which you would like
hot water to be available (time bands are selected in 30 minute notches). Press
the knob to store the time band setting in the appliance memory.
Next set the water temperature to the desired level by turning the “SET” knob
and clicking to memorize the setting; the appliance starts to work in “P1” or “P2”
mode.
If you have selected “P1 and P2”, you need to repeat the time band and
temperature setting procedures for the second programme.
Default settings
The programmes “P1” and “P2” are set by default to the 07:00 and 19:00 time
bands and to a temperature of 70 °C.
When one of the programming functions (“P1” or “P2” or “P1 and P2”) is enabled, the “SET” knob is
disabled. If it is moved, “Pr” appears on the display for 3 seconds. If you wish to adjust the parameters, you
have to press the “SET” knob.
During the periods for which the use of water has not been scheduled, water heating is disabled. The
individual “P1” or “P2” programmes are of equal importance and may be configured independently by the
user for greater flexibility.
If the product is disconnected by the power mains for a long period, all the settings are stored into the
appliance memory except for the local time which has to be set again (when the product is switched on, the
appliance works in MANUAL mode until the local time is set again, resuming all the stored settings).
3.3 ECO
The ECO function is a software program which automatically "learns" the consumption levels of the user,
helping to minimise heat dispersion while maximising the amount of energy saved.
The operation of the ECO software consists in an initial memorising period which lasts one week, during
which the product begins operating at the temperature set by the user and adjusts it every day to energy
requirements in order to maximise the amount of energy saved. At the end of this “learning” week, the
ECO software begins activating the water heating process in accordance with the time periods and
quantities selected automatically by the product after it has finished to “learn” the user tapping profile. The
product ensures a store of hot water even during the periods when hot water production has not been
scheduled.
To activate the ECO function press the corresponding “ECO” button, which lights up; to deactivate the ECO
function press the illuminated “ECO” button, which is switched off.
While the ECO function is active, manual temperature selection is disabled (the “SET” knob is disabled)
because the temperature is set automatically by the product. If you wish to increase or decrease the
temperature, the ECO function must be deactivated.
Whenever the ECO function or the product itself is switched off and then on again, the function starts up
from the beginning of the “learning” period. In order to ensure the ECO function operates correctly, we
recommend the product is not disconnected from the electricity supply.

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3.4 ECO PLUS
Only for VLS PREMIUM version.
If one of the programming modes (“P1” or “P ” or “P1 and P ”) is used in conjunction with the “ECO”
function, the temperature is set automatically by the appliance and the desired time band for hot water
availability is set manually by the end user. This operating mode maximises the amount of energy saved.
If the “SET” knob is moved, “PLUS” appears on the display for 3 seconds, indicating the simultaneous
operation of these two functions.
3.5 Anti-bacteria
The anti-bacteria function consists in a water heating cycle at 70 °C which carries out a thermal disinfection
action against the relevant bacteria.
The first cycle begins 3 days after the function activation. Subsequent cycles are performed every 30 days
(if, during that period, the water is not heated to 70 °C at least once). At the end of every cycle, the
operating temperature reverts to the value set previously by the user.
When the product is switched off, the anti bacteria function is disabled but the days counter is able to run.
If the appliance is switched off during the anti bacteria cycle, the product shuts down and the function is
disabled. When the product is switched on again, the function is active and able to resume its parameters.
After a disconnection by the power mains, when the appliance is connected again, the function is active
and able to work as a first activation has been done by the user.
VLS
How to activate/deactivate
the anti bacteria function
P
ress and hold the “ECO” and
“+” buttons
simultaneously for 4 seconds
:
the
70 °C waves flash rapidly for 4 seconds to confirm the function activation;
the 40 °C waves flash rapidly for 4 seconds to confirm the function
deactivation.
During the anti
bacteria cycle
70 °C
temperature se
tting
is displayed
.
VLS PREMIUM
How to activate/deactivate
the anti bacteria function
To disable/enable the function, while the product is in op
eration, press and
hold the “MODE” button for 3 seconds; select “Ab0” (to disable the
function) or “Ab1” (to enable the function) using the “SET” knob, then
confirm by pressing the knob.
After having confirmed that the function has been disabled/enabled
successfully, the product reverts to its normal operating status.
During the anti bacteria cycle
T
he display alternates between the
t
emper
ature of the water and the text
“ Ab ”.

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4. Troubleshooting and maintenance
4.1 Displayed faults
VLS
How the appliance
shows errors
All WAVES, corresponding temperature icons, “SHOWER READY” icon and “ECO”
button flash simultaneously.
How to do
(manual reset)
Reset the appliance
switch
ing
the product off and on again using the
ON/OFF
button. If the cause of the error disappears immediately following the reset process,
the appliance resumes normal operation. If this is not the case, the “faulty status”
continues to appear on the HMI; contact the Technical Assistance Centre.
Instruction for competent and skilled technical orkers only
How to enter
the diagnostic
Press and hold the ON/OFF button for 5 seconds;
the “ECO” button and the
“SHOWER READY” icon are switched off.
If the ON/OFF button is pressed or if any actions are not performed for 25 seconds,
the appliance resumes its “faulty status”.
NON
volatile errors
(the appliance is
unable to work until
the error has been
solved and a manual
reset has been
done)
60 °C, 70 °C, 80 °C
and corresponding
“WAVES” icons
switched on
High temperature into the outlet tank due to:
lack of water  if the water heater is empty, fill it;
HE1 probe incorrect positioning  if the component is
not entirely into the HE1 sheath, place it in the right
position;
HE1 sensor/s out of tune  if the component is faulty
(values not in compliance with “Sensor Test Table”),
replace it.
50 °C, 60 °C, 70 °C, 80 °C
and corresponding
“WAVES” icons
switched on
High temperature into the inlet tank due to:
lack of water  if the water heater is empty, fill it;
HE2 probe incorrect positioning  if the component is
not entirely into the HE2 sheath, place it in the right
position;
HE2 sensor/s out of tune  if the component is faulty
(values not in compliance with “Sensor Test Table”),
replace it.
80 °C and corresponding
“WAVES” icons
switched on
Overheated water into the outlet tank due to:
HE1 probe incorrect positioning  if the component is
not entirely into the HE1 sheath, place it in the right
position;
HE1 sensor/s out of tune  if the component is faulty
(values not in compliance with “Sensor Test Table”),
replace it.
50 °C, 80 °C and
corresponding “WAVES”
icons switched on
Overheated water into the inlet tank due to:
HE2 probe incorrect positioning  if the component is
not entirely into the HE2 sheath, place it in the right
position;
HE2 sensor/s out of tune  if the component is faulty
(values not in compliance with “Sensor Test Table”),
replace it.
70 °C, 80 °C and
corresponding “WAVES”
icons switched on
HE1 functional relay stuck due to:
faulty component  if a short circuit occurs between
the HE1 power terminals on the PCB, replace the PCB.

14
NON
volatile errors
(the appliance is
unable to work until
the error has been
solved and a manual
reset has been
done)
50 °C, 70 °C, 80 °C and
corresponding “WAVES”
icons switched on
HE2 functional relay stuck due to:
faulty component  if a short circuit occurs between
the HE2 power terminals on the PCB, replace the PCB.
40 °C and corresponding
“WAVES” icons
switched on
Internal fault

Replace the PCB.
Volatile errors
(the appliance is
able to work; if the
error disappears, the
appliance resumes
normal operation)
60 °C, 70 °C and
corresponding “WAVES”
icons switched on
Low heating rate concerning the outlet tank due to:
incorrect appliance horizontal installation  if the
water pipes are on the right, dismount the product
from the wall and make the proper installation;
bad placed or damaged wiring  if the red power
cable is disconnected/damaged, connect/replace it;
faulty component  if the ohmic resistance value
between the HE1 fastons is not in compliance with the
nominal value (R ~ 35 Ω), replace it.
50 °C, 60 °C, 70 °C and
corresponding “WAVES”
icons switched on
Low heating rate concerning the inlet tank due to:
incorrect appliance horizontal installation  if the
water pipes are on the right, dismount the product
from the wall and make the proper installation;
bad placed or damaged wiring  if the blue power
cable is disconnected/damaged, connect/replace it;
faulty component  if the ohmic resistance value
between the HE2 fastons is not in compliance with the
nominal value (R ~ 53 Ω), replace it.
60 °C and corresponding
“WAVES” icons
switched on
HE1 probe short/open circuit due to:
bad placed or damaged wiring/faulty component  if
the component is disconnected or faulty (sensor/s
values not in compliance with “Sensor Test Table”),
connect/replace it.
50 °C, 60 °C and
corresponding “WAVES”
icons switched on
HE2
probe short/open circuit due to:
bad placed or damaged wiring/faulty component  if
the component is disconnected or faulty (sensor/s
values not in compliance with “Sensor Test Table”),
connect/replace it.
60 °C, 80 °C and
corresponding “WAVES”
icons switched on
High difference of
temperature measured by higher and
lower sensors into the outlet tank due to:
HE1 probe incorrect positioning  if the component is
not entirely into the HE1 sheath, place it in the right
position;
HE1 sensor/s out of tune  if the component is faulty
(values not in compliance with “Sensor Test Table”),
replace it.
50 °C, 60 °C, 80 °C and
corresponding “WAVES”
icons switched on
High difference of temperature measured by higher and
lower sensors into the inlet tank due to:
HE2 probe incorrect positioning  if the component is
not entirely into the HE2 sheath, place it in the right
position;
HE2 sensor/s out of tune  if the component is faulty
(values not in compliance with “Sensor Test Table”),
replace it.

15
VLS PREMIUM
How
the appliance
shows error Error code flashes on the LCD display.
How to do
(manual reset)
Reset the appliance
switch
ing
the product off and on again using the
ON/OFF
button. If the cause of the error disappears immediately following the reset
process, the appliance resumes normal operation. If this is not the case, the error
code continues to appear on the LCD display; contact the Technical Assistance
Centre.
Instruction for competent and skilled technical orkers only
NON
volatile errors
(the appliance is
unable to work until
the error has been
solved and a manual
reset has been done)
E01
Internal fault

Replace the PCB.
E11
Overheated water into the outlet tank due to:
HE1 probe incorrect positioning  if the component is not entirely into
the HE1 sheath, place it in the right position;
HE1 sensor/s out of tune  if the component is faulty (values not in
compliance with “Sensor Test Table”), replace it.
E12
HE1 functional relay stuck due to:
faulty component  if a short circuit occurs between the HE1 power
terminals on the PCB, replace the PCB.
E15
High temperature into the outlet tank due to:
lack of water  if the water heater is empty, fill it;
HE1 probe incorrect positioning  if the component is not entirely into
the HE1 sheath, place it in the right position;
HE1 sensor/s out of tune  if the component is faulty (values not in
compliance with “Sensor Test Table”), replace it.
E21
Overheated water into the inlet tank due to:
HE2 probe incorrect positioning  if the component is not entirely into
the HE2 sheath, place it in the right position;
HE2 sensor/s out of tune  if the component is faulty (values not in
compliance with “Sensor Test Table”), replace it.
E22
HE2 functi
onal relay stuck due to:
faulty component  if a short circuit occurs between the HE2 power
terminals on the PCB, replace the PCB.
E25
High temperature into the inlet tank due to:
lack of water  if the water heater is empty, fill it;
HE2 probe incorrect positioning  if the component is not entirely into
the HE2 sheath, place it in the right position;
HE2 sensor/s out of tune  if the component is faulty (values not in
compliance with “Sensor Test Table”), replace it.
Volatile errors
(the appliance is able
to work powering on
only one HE at a time
and HE1 has the
priority; if the error
disappears, the
appliance resumes
normal operation)
E10
HE1 probe short/open circuit due to:
bad placed or damaged wiring/faulty component  if the component is
disconnected or faulty (sensor/s values not in compliance with “Sensor
Test Table”), connect/replace it.
E13
High difference of temperature measured by higher and lower sensors into
the outlet tank due to:
HE1 probe incorrect positioning  if the component is not entirely into
the HE1 sheath, place it in the right position;
HE1 sensor/s out of tune  if the component is faulty (values not in
compliance with “Sensor Test Table”), replace it.
E14
Low heating
rate concerning the outlet tank due to:
incorrect appliance horizontal installation  if the water pipes are on the
right, dismount the product from the wall and make the proper

16
Volatile errors
(the appliance is able
to work powering on
only one HE at a time
and HE1 has the
priority; if the error
disappears, the
appliance resumes
normal operation)
E14
installation;
bad placed or damaged wiring  if the red power cable is
disconnected/damaged, connect/replace it;
E20
HE2
probe short/open circuit due to:
bad placed or damaged wiring/faulty component  if the component is
disconnected or faulty (sensor/s values not in compliance with “Sensor
Test Table”), connect/replace it.
E23
High difference
of temperature measured by highe
r and lower sensors into
the inlet tank due to:
HE2 probe incorrect positioning  if the component is not entirely into
the HE2 sheath, place it in the right position;
HE2 sensor/s out of tune  if the component is faulty (values not in
compliance with “Sensor Test Table”), replace it.
E24
Low heating rate concerning the inlet tank due to:
incorrect appliance horizontal installation  if the water pipes are on the
right, dismount the product from the wall and make the proper
installation;
bad placed or damaged wiring  if the blue power cable is
disconnected/damaged, connect/replace it;
faulty component  if the ohmic resistance value between the HE2
fastons is not in compliance with the nominal value (R ~ 53 Ω), replace it.
4.2 Malfunctioning
Instruction for competent and skilled technical workers
Info missing
(the button
HMI or the LCD
display is
switched off)
Power missing
to the appliance due to:
no power from mains (could be check by the end user, too)  if the home power
network is not well working, contact the power mains technical service;
power missing to the PCB (could be check by the end user, too)  if the appliance is
switched off, switch on it pressing the ON/OFF button;
bad placed or damaged wirings  if the power cable is disconnected/damaged,
connect/replace it.
Power missing to the button HMI or to the LCD display due to:
bad connection of wirings  if the communication cable between the PCB and the
interface is not well connected, place it in the right position;
bad placed or damaged wirings if the communication cable between the PCB and
the interface is disconnected/damaged, connect/replace it;
PCB break  if the PCB is damaged, replace it.
Button HMI or LCD display broken due to:
faulty component  if the HMI is damaged, replace it.
Water leakage
From
the
pipe
due to:
wrong pipe tightening  if the inlet/outlet pipe is bad connected and water comes
out from it, restore the connection.
From the tank flange due to:
wrong flange tightening  if water comes out from the flange, check the flange bolts
tightening;
damaged gasket  if the component is broken, replace it.
From the safety valve due to:
drainage pipe missing  a drip of water by the device should be considered normal
during/after the heating phase; if the drainage pipe is missing, place it;

17
Water leakage
drainage hole obstructed

if the hole is obstructed, clean it and, if necessary, install
upriver the safety valve a proper softener to reduce water hardness or a filter to avoid
dirt and dust coming from the network;
damaged drainage pipe  if the pipe is broken, replace it;
high water network pressure  if the water network pressure is high, install a
pressure reducer up river the safety valve or a tailored expansion vessel between the
safety valve and the appliance inlet pipe;
high water temperature set point  if the hot water temperature set point is high,
reduce it up to end user comfort is anyway satisfying or install a tailored expansion
vessel between the safety valve and the appliance inlet pipe.
From the by pass pipe between the two tanks due to:
wrong pipe tightening  if the pipe is bad connected and water comes out from it,
restore the connection;
faulty component  if the by pass pipe is damaged, replace it.
From the heating element fastons due to:
corrosion  if the heating element is damaged and water can enter, replace it.
From the tank due to:
corrosion  if the tank is damaged and water spills out, replace the product.
Insufficient
water
temperature
Power missing to the appliance due to:
no power from mains (could be check by the end user, too)  if the home power
network is not well working, contact the power mains technical service;
power missing to the PCB (could be check by the end user, too)  if the appliance is
switched off, switch on it pressing the ON/OFF button;
bad placed or damaged wirings  if the power cable is disconnected/damaged,
connect/replace it.
Incorrect appliance working mode settings:
low water temperature set point (could be check by the end user, too)  if the set
point is not able to satisfy the end user comfort request, adjust the set point;
occasional huge hot water amount (could be check by the end user, too)  if the end
user tapping profile is not predictable, deactivate the ECO function;
incorrect time band in PREMIUM versions (could be check by the end user, too)  if
the programming mode is set and the time band is not in compliance with the end
user comfort request, adjust the time band.
Incorrect thermostatic mixing valve setting (if present) due to:
low water temperature set point  if the thermostatic mixing valve set point is not in
compliance with the end user comfort request, adjust the set point;
faulty component  if the thermostatic mixing valve is damaged or out of tune,
replace it.
Inlet plastic pipe broken due to:
faulty component  if the component is damaged, replace it.
Insufficient
water flow
Low
water network pressure
(
could be check by the end user, too
)

if the cold water
network pressure is less than 2 bar, check if the home mains tap is fully open, if any
leakage is present upriver the water heater or contact the network technical service.
Inlet plastic pipe malfunctioning due to:
component break  if the component is damaged, replace it;
Pipes (inlet pipe or outlet pipe or by pass between the two tanks) or safety valve
clogged due to:
limestone  if limestone is present, clean it and, if necessary, install a proper
softener upriver the safety valve to reduce water hardness;
dirt and dust if dirt or dust is present, clean it and, if necessary, install a filter
upriver the safety valve.
Filter obstructed (if present, anywhere in the circuit) due to:
limestone  if limestone is present, clean the filter and, if necessary, install a proper

18
Insuffi
cient
water flow
softener upriver the safety valve to reduce water hardness;
dirt and dust if dirt or dust is present, clean the filter.
Boiler water or
steam from
taps
Incorrect appliance working mode settings:
high water temperature set point (could be check by the end user, too)  if the set
point is not able to satisfy the end user comfort request, adjust the set point.
Incorrect thermostatic mixing valve setting (if present) due to:
high water temperature set point  if the thermostatic mixing valve set point is not
in compliance with the end user comfort request, adjust the set point;
faulty component  if the thermostatic mixing valve is damaged or out of tune,
replace it.
Low sensors sensitivity due to:
high level of limestone into the tank  if the heating element is widely covered by
limestone, clean it and, if necessary, install a proper softener upriver the safety valve
to reduce water hardness.
Noise during
the heating
phase
Incorrect appliance horizontal installation

if the water pipes are o
n the right,
dismount the product from the wall and make the proper installation.
High level of limestone into the tank  if the heating element is widely covered by
limestone, clean it and, if necessary, install a proper softener upriver the safety valve to
reduce water hardness.
Bad water
quality
Dust and dirt
(
could be check by the end user, too
)

if
the
cold water has a bad quality
because of dust and dirt presence, contact the network technical service.
Pipes connection corrosion due to:
different materials matching  if different metallic materials are used in the circuit,
provide dielectric joints between them.
“Shower ready”
icon/symbol
often off
Incorrect jumpers setting
on
the
PCB

if
the
PCB
jumpers
have a
different position
from what depicted at paragraph 2.5, set them properly.
4.3 Routine maintenance
All maintenance operations and service visits should be performed by a competent person (who have the
skills required by the applicable norms in force).
The pressure safety device must be enabled regularly (once a month) to remove the limestone deposits
and to check that it is not clogged.
Replace the Mg anodes every two years. To remove them, disassemble the heating elements and unscrew
them from the support bracket.
To ensure the best performance from this appliance, descale the heating element once every two years. If
you prefer not to use special descaling acids for this operation, simply crumble away the lime deposit
without damaging the heating element.