Vaillant ecoTEC plus VU Series User manual

en Operating instructions
ecoTEC plus
VU../VUW../VUI..
0020308119_02 - 28.11.2022

2Operating instructions 0020308119_02
Operating instructions
Contents
1 Safety ............................................ 3
1.1 Intended use .................................. 3
1.2 Qualification ................................... 3
1.3 General safety information............. 3
2 Notes on the documentation ...... 6
3 Product description..................... 6
3.1 Display and control elements......... 6
3.2 Displayed symbols......................... 7
3.3 Serial number ................................ 7
3.4 CE marking .................................... 7
3.5 UKCA mark.................................... 8
3.6 Hot Water Association ................... 8
3.7 Benchmark..................................... 8
4 Operation...................................... 8
4.1 Operating concept ......................... 8
4.2 Setting the language...................... 9
4.3 Activating/deactivating the
button lock ................................... 10
4.4 Heating mode .............................. 10
4.5 DHW mode .................................. 10
4.6 Using the sensoROOM pure
(VRT 50/2) room temperature
control .......................................... 11
4.7 Calling up status codes................ 13
5 Care and maintenance .............. 13
5.1 Caring for the product .................. 13
5.2 Maintenance ................................ 13
5.3 Reading maintenance
messages .................................... 13
5.4 Maintaining the pressure of the
heating system............................. 13
5.5 Checking the condensate
discharge pipe and tundish.......... 16
6 Troubleshooting ........................ 16
7 Decommissioning...................... 16
7.1 Temporarily decommissioning
the product................................... 16
7.2 Permanently decommissioning
the product................................... 16
8 Restarting ................................... 16
9 Recycling and disposal............. 17
10 Guarantee and customer
service ........................................ 17
10.1 Guarantee.................................... 17
10.2 Customer service......................... 17
Appendix ............................................... 18
A End user level ............................ 18
A.1 Additional functions...................... 19
B Status codes .............................. 19
C Fault codes/limp home mode
codes .......................................... 20
D Troubleshooting ........................ 20

0020308119_02 Operating instructions 3
1 Safety
1.1 Intended use
The product is intended as a
heat generator for sealed heat-
ing installations and for do-
mestic hot water generation.
Intended use also includes the
following:
–Using the product while ob-
serving the operating instruc-
tions included for the product
and any other installation
components
–Observing all inspection and
maintenance intervals listed in
the instructions
Any other use that is not spe-
cified in these instructions, or
use beyond that specified in this
document, shall be considered
improper use.
Improper use of any kind is
prohibited.
1.2 Qualification
▶Employ only a qualified com-
petent person to install, con-
vert and set the product.
As the end user, you may carry
out all of the work that is de-
scribed in these instructions.
Exception: This product can be
used by children aged from 8
years and above and persons
with reduced physical, sensory
or mental capabilities or lack of
experience and knowledge if
they have been given supervi-
sion or instruction concerning
use of the product in a safe way
and understand the hazards in-
volved. Children must not play
with the product. Cleaning and
user maintenance work must
not be carried out by children
unless they are supervised.
Work that is described in other
instructions must only be car-
ried out by persons who meet
the requirements described
therein.
1.3 General safety
information
The following sections convey
important safety information. It
is essential to read and observe
this information in order to pre-
vent risk of death, risk of injury,
material damage or environ-
mental damage.
1.3.1 Gas
If you smell gas:
▶Avoid rooms that smell of
gas.
▶If possible, open doors and
windows fully and ensure
adequate ventilation.
▶Do not use naked flames (e.g.
lighters, matches).
▶Do not smoke.
▶Do not use any electrical
switches, mains plugs, door-

4Operating instructions 0020308119_02
bells, telephones or other
communication systems in
the building.
▶Close the emergency control
valve or the main isolator.
▶If possible, close the gas
stopcock on the product.
▶Warn other occupants in the
building by yelling or banging
on doors or walls.
▶Leave the building immedi-
ately and ensure that others
do not enter the building.
▶Alert the police and fire bri-
gade as soon as you are out-
side the building.
▶Use a telephone outside the
building to inform the emer-
gency service department of
the gas supply company.
1.3.2 Risk of death from
escaping gas
What to do if you smell gas in
the building:
▶Avoid rooms that smell of
gas.
▶If possible, open doors and
windows fully and ensure
adequate ventilation.
▶Do not use naked flames (e.g.
lighters, matches).
▶Do not smoke.
▶Do not use any electrical
switches, mains plugs, door-
bells, telephones or other
communication systems in
the building.
▶If it is safe to do so, close the
emergency control valve or
the main isolator.
▶If possible, close the gas
stopcock on the product.
▶Warn other occupants in the
building by yelling or banging
on doors or walls.
▶Leave the building immedi-
ately and ensure that others
do not enter the building.
▶Notify the gas supply
company or the Emer-
gency Service Provider
[phone] by tele-
phone once you are outside
of the building.
1.3.3 Flue gas
If you smell flue gas:
▶Open all accessible doors
and windows fully to provide
ventilation.
▶Switch off the product.
▶Contact a competent person.
1.3.4 Subsequent product
modifications
▶Never remove, bridge or
block the safety devices.
▶Do not tamper with any of the
safety devices.
▶Do not damage or remove
any tamper-proof seals on
components.
▶Do not make any changes:
–The product itself

0020308119_02 Operating instructions 5
–to the gas, supply air, water
and electricity supply lines
–to the entire flue system
–to the entire condensate dis-
charge system
–to the expansion relief valve
–to the drain pipework
–to constructional conditions
that may affect the operational
reliability of the product
▶Ensure that there is an evenly
sufficient combustion air sup-
ply.
1.3.5 Material damage
▶Ensure that the combustion
air supply is always free of
fluorine, chlorine, sulphur,
dust, etc.
▶Ensure that no chemical sub-
stances are stored at the in-
stallation site.
▶During a period of frost, en-
sure that the heating install-
ation remains in operation
and that all rooms are heated,
even when you are away.
–If a control is installed,
switch the product on and
off using the control to keep
the frost protection devices
active.
▶If you cannot ensure the oper-
ation, have a competent per-
son drain the heating installa-
tion.
▶Only fill the heating installa-
tion with suitable heating wa-
ter and, in cases of doubt, ask
a competent person about
this.
1.3.6 Legionella
▶Have a competent person in-
form you about the measures
that should be taken to pro-
tect against Legionella in your
installation.
▶Do not set any water temper-
atures below 60 °C without
consulting the competent per-
son first.

6Operating instructions 0020308119_02
2 Notes on the
documentation
▶Always observe all operating instruc-
tions enclosed with the installation com-
ponents.
▶Store these instructions and all other
applicable documents for further use.
These instructions apply for the following
products only:
Product article number
VU 10CS/1-5 (N-GB)
ecoTEC plus 610
0010036009
VU 15CS/1-5 (N-GB)
ecoTEC plus 615
0010036010
VU 20CS/1-5 (N-GB)
ecoTEC plus 620
0010036011
VU 25CS/1-5 (N-GB)
ecoTEC plus 625
0010036012
VU 30CS/1-5 (N-GB)
ecoTEC plus 630
0010036013
VU 35CS/1-5 (N-GB)
ecoTEC plus 635
0010036014
VUW 20/26CS/1-5 (N-GB)
ecoTEC plus 826
0010036015
VUW 25/32CS/1-5 (N-GB)
ecoTEC plus 832
0010036016
VUW 30/36CS/1-5 (N-GB)
ecoTEC plus 836
0010036017
VUW 30/40CS/1-5 (N-GB)
ecoTEC plus 840
0010036018
VUI 30/40CS/1-5 (N-GB)
ecoTEC plus 940
0010036114
Gas Council Numbers
VU 10CS/1-5 (N-GB) ecoTEC
plus 610
41-694-45
VU 15CS/1-5 (N-GB) ecoTEC
plus 615
41-694-46
VU 20CS/1-5 (N-GB) ecoTEC
plus 620
41-694-47
VU 25CS/1-5 (N-GB) ecoTEC
plus 625
41-694-48
VU 30CS/1-5 (N-GB) ecoTEC
plus 630
41-694-49
VU 35CS/1-5 (N-GB) ecoTEC
plus 635
41-694-50
VUW 20/26CS/1-5 (N-GB)
ecoTEC plus 826
47-044-92
VUW 25/32CS/1-5 (N-GB)
ecoTEC plus 832
47-044-93
VUW 30/36CS/1-5 (N-GB)
ecoTEC plus 836
47-044-94
VUW 30/40CS/1-5 (N-GB)
ecoTEC plus 840
47-044-95
VUI 30/40CS/1-5 (N-GB)
ecoTEC plus 940
47-044-96
3 Product description
3.1 Display and control elements
Control
element
Function
–Activate/deactivate standby
mode: Press for less than three
seconds
–Reset button: Press and hold
for more than three seconds to
restart
Setting the desired flow temperat-
ure from the boiler
Setting the desired domestic hot
water temperature from the boiler
–Calling up help
–Calling up the time programme
assistant (control module)
–Go one level back
–Cancelling input
–Calling up the menu
–Back to the main menu
–Calling up the basic display
–Confirming a selection/change
–Saving the set value
Call up chimney sweep mode
(carry out combustion analysis).
For competent persons only.

0020308119_02 Operating instructions 7
Control
element
Function
–Navigating through the menu
structure
–Reducing or increasing the set
value
–Navigating to individual num-
bers and letters
3.2 Displayed symbols
Symbol Meaning
Current burner modulation rate
(display in five levels).
Current system pressure
(display in five levels):
–Permanently on: Filling pres-
sure in the permitted range
–Flashing: Filling pressure
outside the permitted range
Heating mode activated:
–Permanently on: Burner off,
no heat demand
–Flashing: Burner on, heat
demand present
Heating mode is switched off
Domestic hot water generation
activated:
–Permanently on: Burner off,
no heat demand
–Flashing: Burner on, heat
demand present
Product with integrated do-
mestic hot water generation
or product with connected
domestic hot water cylinder
Comfort mode activated:
–Permanently on: Comfort
mode is activated
–Flashing: Burner on, comfort
mode on
Installer level active
Display locked
Connected to the system con-
trol
Connection to the Vaillant
server established
Symbol Meaning
Product is busy with a task.
Setting the time:
–Permanently on: Time is set
–Flashing: The time must be
reset
Warning
Fault in the product:
Appears instead of the basic
display, may be an explanatory
plain text display.
Limp home mode:
Appears instead of the basic
display, may be an explanatory
plain text display.
Maintenance required:
You can find more information
in code I.XXX.
Maintenance required:
Appears instead of the basic
display, may be an explanatory
plain text display.
3.3 Serial number
The serial numbers are located on the
underside of the front panel and on the
data plate.
The 3rd to 6th digits provide the produc-
tion date (year/week), the 7th to 16th digit
provide the article number for the product.
3.4 CE marking
The CE marking shows that the products
comply with the basic requirements of the
applicable directives as stated on the de-
claration of conformity.
The declaration of conformity can be
viewed at the manufacturer's site.

8Operating instructions 0020308119_02
3.5 UKCA mark
The UKCA marking shows that the
products comply with the basic require-
ments of the applicable directives as
stated on the declaration of conformity.
The declaration of conformity can be
viewed at the manufacturer's site.
3.6 Hot Water Association
Vaillant is a full member of the Hot Water
Association and promotes the scheme
in association with its cylinder range.
Details are available on the web site
www.vaillant.co.uk
3.7 Benchmark
Vaillant is a licensed member of the
Benchmark Scheme which aims to im-
prove the standards of installation and
commissioning of domestic heating and
hot water systems in the UK and to en-
courage regular servicing to optimise
safety, efficiency and performance.
Benchmark is managed and promoted
by the Heating and Hotwater Industry
Council. For more information visit
www.benchmark.org.uk.
▶Please ensure that the installer has fully
completed the Benchmark Checklist on
the inside back pages of the installation
instructions supplied with the product
and that you have signed it to say that
you have received a full and clear ex-
planation of its operation. The installer
is legally required to complete a com-
missioning checklist as a means of
complying with the appropriate Build-
ing Regulations (England and Wales).
All installations must be notified to Local
Area Building Control either directly or
through a Competent Persons Scheme.
A Building Regulations Compliance Certi-
ficate will then be issued to the customer
who should, on receipt, write the Notifica-
tion Number on the Benchmark Checklist.
This product should be serviced regularly
to optimise its safety, efficiency and per-
formance. The service engineer should
complete the relevant Service Record on
the Benchmark Checklist after each ser-
vice.
The Benchmark Checklist will be required
in the event of any warranty.
4 Operation
4.1 Operating concept
Control elements that are lit up in colour
can be selected.
Adjustable values and list entries can be
changed using the scrollbar. Briefly tap on
the top and bottom end of the scrollbar in
order to implement changes.
You must confirm a change to a value.
Only then is the new setting saved. You
have to press flashing control elements
again to confirm.
Control elements that are lit up in white are
active.
The menu and the control elements are
dimmed after 60 seconds in order to save
energy. The status display is shown after
another 60 seconds.
You can find additional assistance for the
control elements under MAIN MENU →
INFORMATION →Control elements.

0020308119_02 Operating instructions 9
4.1.1 Basic display
If the status display is shown, press to
call up the basic display.
In the basic display, you can set the de-
sired domestic hot water temperature and
flow temperature/desired temperature
(desired temperature only available for
products with a control module).
The flow temperature is the temperature
at which the heating water leaves the heat
generator (e.g. 65 °C).
The desired temperature is the temper-
ature that is actually desired for the living
room (e.g. 21 °C).
Press to set the temperature for do-
mestic hot water mode.
Press to set the temperature for heat-
ing mode.
Further settings for heating mode and do-
mestic hot water mode are described in
the relevant sections.
If the basic display is shown, press to
call up the menu.
The functions that are available in the
menu depend on whether a system control
is connected to the product. If you have
connected a system control, the settings
for heating mode must be available in the
system control. (→System control operat-
ing instructions)
You can find additional assistance for the
navigation under MAIN MENU →INFORM-
ATION →Menu introduction.
If there is an error message present, the
basic displays switches to the error mes-
sage.
Note
If a code request appears after you
press , your competent person
has locked access to the control
panel in order to prevent settings
from being accidentally changed.
Contact your competent person.
4.1.2 Operating levels
If the basic display is shown, call up the
menu in order to display the end user
level.
In the end user level, you can change
and individually adapt the settings for the
product. The table in the appendix lists the
menu items and setting options that can
be selected. (→Appendix A)
A timer is built into the boiler for the heat-
ing circuit but is only activated and vis-
ible with the use of a Vaillant sensoROOM
pure (VRT 50/2) control.
The installer level must only be operated
by persons with expertise and is therefore
protected by a code.
4.2 Setting the language
1. Press twice.
2. Navigate to the bottom menu item
(XXX) and confirm by pressing
.
3. Select the third menu item and con-
firm by pressing .
4. Select the first menu item and confirm
by pressing .
5. Select the required language and con-
firm by pressing .

10 Operating instructions 0020308119_02
4.3 Activating/deactivating the
button lock
1. Call up MAIN MENU →SETTINGS →
Button lock.
2. Confirm by pressing .
–The button lock is activated.
3. To deactivate the button lock, press
and hold for four seconds.
4.4 Heating mode
In heating mode, the rooms are heated up
in accordance with your settings.
4.4.1 Setting the flow temperature
Validity: Product without connected sensoROOM
pure (VRT 50/2) AND Product without system control
▶From the basic display, press .
◁The flow temperature that has
already been set is shown in the
display.
▶Set the desired flow temperature.
Validity: Product with connected sensoROOM pure
(VRT 50/2) OR Product with system control
▶Set the desired temperature on the
control or room temperature control;
see operating and installation instruc-
tions for the control or room temperat-
ure control.
4.4.2 Permanently switching off
heating mode (summer mode)
Validity: Product without connected sensoROOM
pure (VRT 50/2)
▶From the basic display, press for
at least three seconds.
◁Heating mode is switched off.
◁The symbol for heating mode
is shown as deactivated in the
display.
Validity: Product with connected sensoROOM pure
(VRT 50/2)
▶Set the lowest target room temperat-
ure on the room temperature control;
see operating and installation instruc-
tions for the room temperature con-
trol.
◁Heating mode is switched off.
Note
If the sensoROOM pure
(VRT 50/2) room temperature
control is connected, you
cannot set the desired temper-
ature on the product's control
panel.
4.5 DHW mode
Validity: Product with integrated hot water genera-
tion OR Product with connected domestic hot water
cylinder
In domestic hot water mode, the potable
water is heated to the required domestic
hot water temperature.
4.5.1 Setting the domestic hot water
temperature
1. From the basic display, press .
2. Set the required domestic hot water
temperature.
4.5.2 Switching off the domestic hot
water mode
Validity: Product with connected domestic hot wa-
ter cylinder OR Product with integrated hot water
generation and shift-load cylinder
▶Starting from the basic display, press
for at least five seconds.
◁The domestic hot water mode is
switched off.
4.5.3 Switching comfort mode
on/off
Note
Comfort mode keeps the domestic
hot water generation ready and
supplies hot water at the desired
temperature without you having to
wait for the heat-up time.

0020308119_02 Operating instructions 11
Validity: Product without connected sensoROOM
pure (VRT 50/2)
▶Call up MAIN MENU →CONTROL →
Comfort mode.
▶Activate On or Off.
Validity: Product with connected sensoROOM pure
(VRT 50/2)
▶Switch the warm start (comfort func-
tion) on and off at the room temper-
ature control, see operating and in-
stallation instructions for the room
temperature control.
Note
Prerequisite: The comfort
mode is activated on the
product.
4.5.4 Activating the shift-load
cylinder
Validity: Product with integrated hot water genera-
tion and shift-load cylinder
The comfort mode for activating the
actoSTOR shift-load cylinder is already
switched on at the factory.
▶Set the domestic hot water temperat-
ure.
Condition: Cylinder charging switched on
–Hot water temperature: 50 to 65 ℃
Danger!
Risk of scalding!
The products are equipped
with an automatic anti-legion-
ella function: If the temperat-
ure in the shift-load cylinder
falls below 50 °C for 24 hours,
the cylinder is heated up to 70
°C once.
▶Please note when drawing
water that it can be very
hot.
▶If you want to switch off the Anti-le-
gionella function, ask a competent
person about this.
▶If you want to switch off cylinder
charging, deactivate comfort mode.
(→Section 4.5.3)
Condition: Cylinder charging switched off
–Hot water temperature: 35 to 65 ℃
◁The cylinder is not maintained at a
specific temperature. If you draw
off the water, the product switches
on and, in this case, only operates
as an instantaneous water heater.
4.6 Using the sensoROOM pure
(VRT 50/2) room temperature
control
Validity: Product with connected sensoROOM pure
(VRT 50/2)
If a sensoROOM pure (VRT 50/2) room
temperature control is connected, this ad-
ditional function is automatically available
in the heat generator and it offers the op-
tion to control the room control timings.
It represents the digital further develop-
ment of the familiar control process via
timeSWITCH.
The temperature is controlled directly at
the room temperature control. On the
heat generator's control panel, the time
control can be switched on/off and the
time period settings can be implemented.
Switching the time control on/off
You have two options:
–Continuous heating (Heating timer =
Off)
–Time-dependent heating (Heating
timer = On)
Activate the time control on the heat gen-
erator. (→Section 4.4.2)
Setting time periods
Prerequisite: Heating timer = On
You have two options:
–Direct configuration of daily schedules
in the weekly planner
–Configuration of the time periods with
the time programme assistant

12 Operating instructions 0020308119_02
Set the time periods on the heat generat-
or's control panel. (→Section 4.6.2)
Switching off heating mode
The heating mode can only be switched
off by decreasing the target room tem-
perature to the minimum value of 15 °C.
(→Section 4.4.2)
Note
The level of the minimum target
room temperature can be de-
creased even further (5 °C), see
the operating and installation in-
structions for the room temperat-
ure control.
4.6.1 Switching the time control
on/off
Validity: Product with connected sensoROOM
pure (VRT 50/2)
1. Call up MAIN MENU →CONTROL
→Heating timer.
2. Activate On or Off.
4.6.2 Setting the time period using
the weekly planner
Validity: Product with connected sensoROOM
pure (VRT 50/2)
Set the time periods on the control panel
on the product instead of on the room
temperature control.
Call up MAIN MENU →CONTROL →
Heating timer →Weekly planner.
Note
The weekly planner automatically
switches on the Heating timer
function if this function was deac-
tivated.
You can use a separate weekly planner
for heating mode for:
24 °C
18:0016:30 22:30
16 °C
21 °C
20:00
A
B
1
3
4
2
55 5
A Time
B Temperature
1 Time period 1
2 Time period 2
3 Desired temper-
ature
4 Set-back tem-
perature
5 Outside of the
time periods
Time periods are already set for each
day of the week at the factory.
You can divide a day up into several
time periods (3) and (5). Each time
period can comprise an individual start
time and end time. The time periods
must not overlap. You can assign a dif-
ferent desired temperature (1) to each
time period.
Example:
16:30 to 18:00; 21 °C
20:00 to 22:30; 24 °C
The living rooms are regulated to the de-
sired temperature within the time peri-
ods. In the times outside of the time peri-
ods (4), the living rooms are regulated to
the lower set-back temperature (2) that
is set.
For heating mode, you can save up
to 12 time periods for each day of the
week. You can set an individual desired
temperature for each time period. The
set desired temperature applies within
these time periods. The set-back tem-
perature applies outside of these time
periods.

0020308119_02 Operating instructions 13
Ī ĭ İ ij īĬ īį īIJ Ĭī ĬĮ
The active list entry is displayed lit up in
white.
You can use Copy settings to… to
transfer start and end time periods that
have already been programmed to an-
other day of the week.
You can find simplified programming of
the time periods for heating mode under
MAIN MENU →CONTROL →Time pro-
gramme assistant.
4.6.3 Setting time periods using the
time programme assistant
Validity: Product with connected sensoROOM
pure (VRT 50/2)
You can use a time programme assist-
ant for heating mode.
Call up MAIN MENU →CONTROL →
Time programme assistant.
The time programme assistant guides
you through the planning. There is a
block for Mon–Fri and Sat–Sun.
The time programme assistant over-
writes the weekly planner that has been
created for heating mode.
4.7 Calling up status codes
▶Call up MENU →INFORMATION →
Status code.
Status codes (→Appendix B)
◁The current operating mode (status
code) is shown on the display.
5 Care and maintenance
5.1 Caring for the product
▶Clean the casing with a damp cloth and
a little solvent-free soap.
▶Do not use sprays, scouring agents,
detergents, solvents or cleaning agents
that contain chlorine.
5.2 Maintenance
An annual inspection of the product carried
out by a competent person is a prerequis-
ite for ensuring that the product is perman-
ently ready and safe for operation, reliable,
and has a long working life.
5.3 Reading maintenance
messages
If the symbol is shown in the display,
the product requires maintenance work.
The product is not in fault mode but contin-
ues to operate.
▶Consult a competent person about this.
▶If the water pressure is flashing at the
same time, simply add more heating
water.
5.4 Maintaining the pressure of the
heating system
5.4.1 Checking the filling pressure of
the heating installation
You have multiple options for reading the
filling pressure of the heating installation.
–On the basic display, as a value on the
bottom right on the display.
–On the basic display, as a symbol on
the upper edge (five stage bars).
–On the INFORMATION menu, as a
value compared to the minimum and
maximum filling pressure.
▶Call up MAIN MENU →INFORMATION
→Water pressure:.
◁The value for the current filling pres-
sure appears on the display.
▶Check the filling pressure in the display.

14 Operating instructions 0020308119_02
▶We recommend a filling pressure of at
least 1 bar (0.1 MPa). If the filling pres-
sure is lower than 0.8 bar (0.08 MPa),
top up the heating water and, in doing
so, increase the excess pressure in the
heating installation.
5.4.2 Topping up and purging the
heating installation
Caution.
Risk of material damage due
to heating water that is ex-
tremely calciferous or corros-
ive or contaminated by chem-
icals.
Unsuitable tap water damages
the seals and diaphragms,
blocks components in the
product and heating installation
through which the water flows
and causes noise.
▶Only fill the heating installa-
tion with suitable heating wa-
ter.
The heating installation is a sealed sys-
tem. Sufficient filling and purging is the
basis for a well-functioning system.
Have your competent person explain the
filling and purging process to you. Each
heating installation is individual.
Proceed as follows: Fill up, purge and
check the pressure. If required, top up
again.
For products with an integrated domestic
hot water generation and products with a
shift-load cylinder, an appropriate filling
device is available. Use the filling device
to fill the heating installation and create the
required excess pressure.
For products with a connected domestic
hot water cylinder, a filling device must be
set up by the competent person and its
use explained.
Recommendation for the excess pres-
sure: At least 1.0 bar (0.1 MPa), max-
imum 2.5 bar (0.25 MPa) with correct act-
ive pressure compensation, good standard
value 1.5 bar (0.15 MPa).
▶Check the height to which the heating
installation extends (highest radiator).
▶For each metre of height, also add
0.1 bar (0.01 MPa) to the minimum
excess pressure.
–Example: Minimum excess pressure
1.0 bar (0.1 MPa) -> Height of the
heating installation 8 m (cellar to roof)
= 0.8 bar (0.08 MPa) -> Target filling
pressure = 1.8 bar (0.18 MPa)
▶Read the pressure level that appears
on the display or on an external mano-
meter, if available. (→Section 5.4.1)
Note
If the pressure that you select is
too high and it reaches the limit
level, the expansion relief valve
opens. If there is no longer suf-
ficient pressure compensation
through the diaphragm expan-
sion vessel, this may already be
the case at the maximum pres-
sure of 2.5 bar (0.25 MPa).
If the pressure is too low, under
certain circumstances, this may
lead to fault message F.22 and
the product temporarily shuts
down. Fault message F.22 goes
out and the product automatic-
ally works again once a certain
pressure level is reached again.

0020308119_02 Operating instructions 15
Validity: Product with integrated hot water generation
OR Product with integrated hot water generation and
shift-load cylinder
4 3
1
2
▶Open all radiator valves (thermostatic
valves) of the heating installation.
▶Fit the double non-return valve (1) of
the filling line to the cold-water isolation
valve and secure the valve with the
spring clip (2).
▶To fill, first open the isolation valve (3).
▶Open the isolation valve (4) so that the
water flows into the heating system. Fill
the heating installation.
▶Monitor the rising filling pressure in the
heating installation.
▶Fill with water until the required filling
pressure is reached.
▶After filling, close isolation valve (4) first
and then isolation valve (3). Disconnect
the filling device by removing the double
non-return valve from the cold-water
isolation valve.
Note
Both isolation valves must be
closed while the heating install-
ation is operating and the filling
line must be removed from the
double non-return valve again.
Validity: Product with connected domestic hot water
cylinder
▶Carry out the filling and purging process
as explained to you by the competent
person.
▶Open the heating water supply.
▶Open all radiator valves (thermostatic
valves) of the heating installation.
▶If necessary, check that both service
valves on the product are open.
▶Slowly open the filling/draining cock
so that the water flows into the heating
installation.
▶Monitor the rising filling pressure in the
heating installation.
▶Fill with water until the required filling
pressure is reached.
▶Close the filling device as explained to
you by the competent person.
The prerequisite for the purging is that
the heating installation is under sufficient
pressure. The heating installation can now
be purged again. Our recommendation:
The heating installation should be purged
once a year before the heating season.
The purging may be varied. If required,
consult your competent person for more
information.
▶Start the purging at the radiators that
are closest to the heat generator, and
continue with the radiators that are po-
sitioned further away. Purge until the
water flows out at the purging valve
without any bubbles.
▶Purge all of the radiators until the entire
heating installation is filled with water.
▶Close all purging valves.
Note
If you notice that the purging
output decreases, check the
pressure in the interim and, if re-
quired, re-establish the target
pressure level by filling the in-
stallation.
Following purging, the pressure level has
fallen.
▶Lastly, check the filling pressure once
again and, if required, adjust this again.

16 Operating instructions 0020308119_02
5.5 Checking the condensate
discharge pipe and tundish
The condensate discharge pipe and tun-
dish must never be blocked and condens-
ate should be able to flow freely.
▶Regularly check the condensate dis-
charge pipe and tundish for faults and,
particularly, for blockages.
You must not be able to see or feel any
obstructions in the condensate discharge
pipe and tundish.
▶If you notice a fault, have it eliminated
by a competent person.
6 Troubleshooting
Danger!
Risk of death caused by im-
proper repair work
▶If the power supply cable is
damaged, never replace this
yourself.
▶Contact the manufacturer,
customer service or a simil-
arly qualified person.
▶If fault codes (F.XXX), LHM codes
(N.XXX) are shown in the display or
faults occur, proceed in accordance
with the tables in the appendix.
Fault codes/limp home mode codes
(→Appendix C)
Troubleshooting (→Appendix D)
▶If you are unable to eliminate the fault
or malfunction using the specified
measures in the tables, contact a
competent person.
▶If N.XXX limp home mode codes are
shown on the display, the system can
still be operated safely; however, please
contact a competent person to have the
fault eliminated.
7 Decommissioning
7.1 Temporarily decommissioning
the product
Condition: Risk of frost
▶Press .
◁The display goes out. The standby
button continues to light up.
◁However, the frost protection for the
heating installation is active.
Condition: No risk of frost
▶Switch off the product at the switched
fused spur box.
◁The display goes out. The product is
not working.
◁The frost protection function is deac-
tivated.
▶Close the gas stopcock on the product.
Validity: Product with integrated hot water generation
OR Product with connected domestic hot water cylin-
der
▶Close the cold-water isolation valve.
7.2 Permanently decommissioning
the product
▶Have a competent person permanently
decommission the product.
8 Restarting
1. If the product was switched off at the
switched fused spur box, switch it
back on there.
◁The display lights up.
2. If the gas stopcock on the product
was closed, open the gas stopcock.
◁The product starts up.
Validity: Product with integrated hot water generation
OR Product with connected domestic hot water cylin-
der
▶Open the cold-water isolation valve.

0020308119_02 Operating instructions 17
9 Recycling and disposal
Disposing of the packaging
▶The competent person who installed
your product is responsible for the dis-
posal of the packaging.
Disposing of the product
If the product is labelled with this
mark:
▶In this case, do not dispose of the
product with the household waste.
▶Instead, hand in the product to a collec-
tion centre for waste electrical or elec-
tronic equipment.
Disposing of batteries
If the product contains batteries that
are labelled with this mark:
▶In this case, dispose of the batteries at
a collection point for batteries.
◁Prerequisite: The batteries can be
removed from the product without
causing any destruction. Otherwise,
the batteries are disposed of to-
gether with the product.
▶In accordance with the legal regula-
tions, used batteries must be returned
since batteries may contain substances
that are harmful to health and the envir-
onment.
10 Guarantee and customer
service
10.1 Guarantee
–Two year guarantee for ecoTEC plus
appliances
–Extended guarantees may apply to your
product and may be subject to certain
installation conditions, please consult
your installer and see Vaillant website
for more information
Vaillant provides this appliance with a
parts and labour guarantee against defects
that may occur within twenty-four months
of the installation date. For the 2nd year of
the guarantee to be valid an annual ser-
vice must be carried out by a competent
person approved at the time by the Health
and Safety Executive one year after install-
ation. The cost of this annual service is not
included in the guarantee.
–Registering with us
Registration is simple. Just complete the
Guarantee Registration Card and return to
Vaillant within 30 days of installation. Your
details will then be automatically registered
within the Vaillant scheme.
–Immediate help
If your Vaillant boiler develops a fault your
first action should be to contact your in-
staller, as his professional assessment is
needed under the terms of our Guarantee.
If you are unable to contact your installer,
phone Vaillant Service Solutions:
Telephone: [phone]
10.2 Customer service
For contact details for our customer ser-
vice department, you can write to the ad-
dress that is provided on the back page, or
you can visit www.vaillant.co.uk.

18 Operating instructions 0020308119_02
Appendix
A End user level
When the status display is displayed, press twice to call up the menu.
CONTROL menu item
Comfort mode: Product with integrated domestic hot water generation or
product with connected domestic hot water cylinder
On: Keeps the domestic hot water generation ready.
INFORMATION menu item
Water pressure: Displays the current water pressure.
Energy data →Gas consumption →Heating
→DHW
→Power consumption →Heating
→DHW
The product, the system control and the app show approximate
values for energy consumption, energy yields and efficiencies,
which are extrapolated based on calculation algorithms.
The values that are displayed in the app may differ from the
other display options due to staggered transfer intervals.
The determined values depend on:
–Installation and system of the heating installation
–User behaviour
–Seasonal weather effects
–Various tolerances of unit-internal components
The values can be read in the following time forms:
–Today
–Yesterday
–Last month
–Last year
–Total
The recording of the values only includes the product in the fact-
ory-delivered condition. Supplementary accessories, even if they
are installed on the product, as well as any other components in
the heating system and other external consumers, are not part of
the data recording.
Deviations between the determined values and the actual values
may be significant. The determined values are therefore not suit-
able for creating or comparing energy billing, for example.
Note
When replacing the PCB, the values recorded up to that point
are completely reset in the product and system control.
Status code Displays the current status code.
Control elements Step-by-step explanation of the individual control elements.
Menu introduction Explanation of the menu structure.
Installer contact info →Phone no.
→Company

0020308119_02 Operating instructions 19
INFORMATION menu item
Software version Displays the software versions.
SETTINGS menu item
Chimney sweep mode →Adjustable heat load
→Max. DHW output
→Min. DHW heat input
Installer level
Language, clock, display
settings
→Language:
→Date:
→Time:
→Display brightness:
→Daylight saving time:
A.1 Additional functions
Validity: Product with connected sensoROOM pure (VRT 50/2)
CONTROL menu item
Heating timer On: Heating mode is permanently switched on.
→Weekly planner
Time programme assistant Programming of the desired temperature for the weekly blocks
Monday-Friday and Saturday-Sunday.
B Status codes
Note
Since the code table is used for various products, some codes may not be vis-
ible for the product in question.
The code table only shows an extract of the entire code.
Code Meaning
S.000 There is no demand for heating mode.
S.002 Heating mode is active and the heating pump is in prerun mode.
S.003 Heating mode is active and the unit ignites.
S.004 Heating mode is active and the burner is operating.
S.006 Heating mode is active and the fan is in overrun mode.
S.007 Heating mode is active and the heating pump is in overrun mode.
S.008 Heating mode is active and the unit is in burner anti-cycling time.
S.012 The domestic hot water draw-off is active and the heating pump is in
prerun mode.
S.013 The domestic hot water draw-off is active and the unit ignites.
S.014 The domestic hot water draw-off is active and the burner is operating.
S.016 The domestic hot water draw-off is active and the fan is in overrun
mode.
S.017 The domestic hot water draw-off is active and the heating pump is in
overrun mode.

20 Operating instructions 0020308119_02
Code Meaning
S.020 There is no demand for the domestic hot water cylinder charging.
S.022 The domestic hot water cylinder charging is active and the pump is in
prerun mode.
S.023 The domestic hot water cylinder charging is active and the unit ignites.
S.024 The domestic hot water cylinder charging is active and the burner is
operating.
S.026 The domestic hot water cylinder charging is active and the fan is in
overrun mode.
S.027 The domestic hot water cylinder charging is active and the heating
pump is in overrun mode.
S.028 The domestic hot water cylinder charging is active and the unit is in
burner anti-cycling time.
S.031 Heating mode has been deactivated and there is no domestic hot water
demand.
S.034 The frost protection function is active.
C Fault codes/limp home mode codes
Note
The code table only shows an extract of the entire code. If fault codes or limp
home mode codes other than those listed are displayed, action by a competent
person is required.
Code/meaning Possible cause Measure
F.022
No/insufficient water
in the product or the
water pressure is too
low.
Water deficiency in
the heating installation
1. Check the filling pressure of the heating
installation. (→Section 5.4.1)
2. Top up with heating water.
(→Section 5.4.2)
F.028
The flame signal was
not detected during
the ignition phase.
After five unsuccessful
ignition attempts, the
product has switched
to fault mode.
1. Check whether the gas stopcock is open.
2. Press the reset button for longer than
three seconds.
–Maximum number of repetitions: 3
3. If you are unable to eliminate the ignition
fault, contact a competent person.
D Troubleshooting
Symptom Possible cause Measure
Product does not start
up (no hot water,
heating remains cold)
The gas isolator cock
installed on-site and/or
the gas isolator cock
on the product is
closed.
▶Open both gas isolator cocks.
The power supply in
the building is discon-
nected.
▶Check the fuse in the building. The product
automatically switches back on when the
power supply is restored.