Vaillant ecoFIT sustain 835 User manual

For the operator
Operating instructions
ecoFIT sustain
825 - 835
GB, IE
Operating instructions
Publisher/manufacturer
Vaillant GmbH
Berghauser Str. 40 D-42859 Remscheid
Tel. [phone]‑0 Fax [phone]‑2810
[email protected] www.vaillant.de

Contents
2Operating instructions ecoFIT sustain 0020230530_01
Contents
1 Safety ............................................ 3
1.1 Action-related warnings ................. 3
1.2 Intended use .................................. 3
1.3 General safety information............. 4
2 Notes on the documentation ...... 7
2.1 Observing other applicable
documents ..................................... 7
2.2 Storing documents......................... 7
2.3 Applicability of the instructions....... 7
3 Product description..................... 7
3.1 Front view ...................................... 7
3.2 Control elements............................ 7
3.3 Displayed symbols......................... 8
3.4 Information on the identification
plate ............................................... 8
3.5 Serial number ................................ 9
3.6 CE label ......................................... 9
3.7 Benchmark..................................... 9
4 Operation.................................... 10
4.1 Operating concept ....................... 10
4.2 Basic display................................ 10
4.3 Adjustment and display levels ..... 10
4.4 Cabinet-type casing ..................... 11
4.5 Opening the isolator devices ....... 11
4.6 Starting up the product ................ 11
4.7 Switching on the product ............. 11
4.8 Setting the heating flow
temperature ................................. 11
4.9 Setting the hot water
temperature ................................. 11
4.10 Switching Comfort mode on and
off................................................. 12
4.11 Switching off the product's
functions ...................................... 12
4.12 Guaranteeing the correct
filling pressure of the heating
system ......................................... 12
4.13 Protecting the heating
installation against frost ............... 13
4.14 Switching the product to
standby mode .............................. 14
5 Troubleshooting ........................ 14
5.1 Detecting and rectifying faults...... 14
5.2 Calling up (Live monitor) status
codes ........................................... 14
6 Care and maintenance .............. 14
6.1 Maintenance ................................ 14
6.2 Caring for the product .................. 14
6.3 Reading maintenance
messages .................................... 14
6.4 Checking the condensate drain
pipework and tundish................... 14
7 Decommissioning...................... 15
7.1 Temporarily decommissioning
the product................................... 15
7.2 Permanently decommissioning
the product................................... 15
8 Recycling and disposal............. 15
9 Guarantee and customer
service ........................................ 15
9.1 Guarantee.................................... 15
9.2 Customer service......................... 15
Appendix ............................................... 16
A Status codes –Overview........... 16
B Troubleshooting ........................ 16

Safety 1
0020230530_01 ecoFIT sustain Operating instructions 3
1 Safety
1.1 Action-related warnings
Classification of action-re-
lated warnings
The action-related warnings
are classified in accordance
with the severity of the pos-
sible danger using the following
warning signs and signal words:
Warning symbols and signal
words
Danger!
Imminent danger to life
or risk of severe personal
injury
Danger!
Risk of death from electric
shock
Warning.
Risk of minor personal
injury
Caution.
Risk of material or envir-
onmental damage
1.2 Intended use
There is a risk of injury or death
to the user or others, or of dam-
age to the product and other
property in the event of im-
proper use or use for which it
is not intended.
The product is intended as a
heat generator for closed heat-
ing installations and for hot wa-
ter generation.
Intended use includes the fol-
lowing:
–observance of the operating
instructions included for the
product and any other system
components
–compliance with all inspection
and maintenance conditions
listed in the instructions.
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.
Any other use that is not spe-
cified in these instructions, or
use beyond that specified in this
document shall be considered
improper use. Any direct com-
mercial or industrial use is also
deemed to be improper.
Caution.
Improper use of any kind is
prohibited.

1 Safety
4Operating instructions ecoFIT sustain 0020230530_01
1.3 General safety
information
1.3.1 Installation by
competent persons only
The installation, inspection,
maintenance and repair of the
product, as well as the gas ratio
settings, must only be carried
out by a competent person.
1.3.2 Danger caused by
improper operation
Improper operation may present
a danger to you and others, and
cause material damage.
▶Carefully read the enclosed
instructions and all other ap-
plicable documents, particu-
larly the "Safety" section and
the warnings.
▶Only carry out the activities
for which instructions are
provided in these operating
instructions.
1.3.3 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 isol-
ator cock 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 com-
pany or the National Grid
[phone] by tele-
phone once you are outside
of the building.
1.3.4 Risk of death due to a
blocked or leaking flue
gas pipe
What to do if you smell flue gas
in the property:
▶Open all accessible doors
and windows fully to provide
ventilation.
▶Switch off the product.
▶Inform a competent person.

Safety 1
0020230530_01 ecoFIT sustain Operating instructions 5
1.3.5 Risk of death due to
explosive and flammable
materials
▶Do not use or store explosive
or flammable materials (e.g.
petrol, paper, paint) in the in-
stallation room of the product.
1.3.6 Risk of death due
to changes to the
product or the product
environment
▶Never remove, bridge or
block the safety devices.
▶Do not tamper with any of the
safety devices.
▶Do not damage or remove
any seals on components.
▶Do not make any changes:
–The product itself
–to the gas, air, water and
electricity supplies
–to the entire flue gas install-
ation
–to the entire condensate
drain system
–to the expansion relief valve
–to the drain pipework
–to constructional condi-
tions that may affect the
operational reliability of the
product
1.3.7 Risk of corrosion
damage due to
unsuitable combustion
and room air
Sprays, solvents, chlorinated
cleaning agents, paint, adhes-
ives, ammonia compounds,
dust or similar substances may
lead to corrosion on the product
and in the air/flue pipe.
▶Ensure that the supply of
combustion air is always free
of fluorine, chlorine, sulphur,
dust, etc.
▶Ensure that no chemical sub-
stances are stored at the in-
stallation site.
1.3.8 Risk of material damage
caused by frost
▶Ensure that the heating in-
stallation always remains in
operation during freezing con-
ditions and that all rooms are
sufficiently heated.
▶If you cannot ensure the op-
eration, have a competent
person drain the heating in-
stallation.

1 Safety
6Operating instructions ecoFIT sustain 0020230530_01
1.3.9 Risk of injury and
material damage due to
maintenance and repairs
carried out incorrectly or
not carried out at all
▶Never attempt to carry out
maintenance work or repairs
on your product yourself.
▶Faults and damage should
be immediately rectified by a
competent person.
▶Adhere to the maintenance
intervals specified.

Notes on the documentation 2
0020230530_01 ecoFIT sustain Operating instructions 7
2 Notes on the
documentation
2.1 Observing other applicable
documents
▶You must observe all operating instruc-
tions enclosed with the system compon-
ents.
2.2 Storing documents
▶Keep this manual and all other applic-
able documents safe for future use.
2.3 Applicability of the
instructions
These instructions apply only to:
Product article number
Article
number
Gas Coun-
cil Number
VUW 256/6-3
(H-GB) 0010020392 47-044-71
VUW 306/6-3
(H-GB) 0010020393 47-044-72
VUW 356/6-3
(H-GB) 0010020394 47-044-73
3 Product description
3.1 Front view
1
2
1 Control elements 2 Plate with serial
number on the
rear
3.2 Control elements
50
1
2
3
1 Fault clearance
key
2 Operating but-
tons
3 Display
3.2.1 Operator control panel
50
1
9
8
7
6
2
3
4
1
5
1 Current heating
flow temperat-
ure, operating
mode, fault code
or additional in-
formation
2 Current assign-
ment of the right-
hand selection
button
3 Left- and right-
hand selection
buttons
4and but-
ton
5 Fault clearance
key

3 Product description
8Operating instructions ecoFIT sustain 0020230530_01
6 Maximum out-
put (only used
for Austria,
Germany and
Switzerland)
7 Access to the
menu for addi-
tional information
8 Current assign-
ment of the left-
hand selection
button
9 Active operating
status
3.3 Displayed symbols
Sym-
bol
Meaning Explanation
Burner operating
correctly
Burner on
bar
Current filling
pressure of the
heating system
The dashed lines
show the permit-
ted range
–Permanently
on: Filling
pressure in
the permitted
range
–Flashing:
Filling pres-
sure outside
the permitted
range
Hot water gener-
ation active
–Permanently
on: Draw-off
mode before
burner is on
–Flashing:
Burner on in
draw-off mode
Heating mode
active
–Permanently
on: Heating
mode heat
requirement
–Flashing:
Burner on in
heating mode
Comfort mode
active
–Permanently
on: Comfort
mode active
–Flashing:
Comfort mode
active, burner
on
Maintenance re-
quired
Information on
the maintenance
message in the
"Live Monitor"
Sym-
bol
Meaning Explanation
Summer mode
active
Heating mode is
switched off
Burner anti-cyc-
ling time is active
To avoid the
need for frequent
switching on and
off (increases the
product's working
life).
F. X X
Fault in the
product
Appears instead
of the basic
display, may be
an explanatory
plain text display.
3.4 Information on the
identification plate
The identification plate is mounted on the
underside of the product in the factory.
The identification plate keeps record of
the country in which the product is to be
installed.
Information
on the identi-
fication plate
Meaning
Barcode with serial number
Serial number For quality control purposes;
3rd and 4th digits = year of
production
For quality control purposes;
5th and 6th digits = week of
production
For identification purposes;
7th to 16th digits = product
article number
For quality control purposes;
17th to 20th digits = place of
manufacture
ecoFIT sustain
8..
Product designation
2H, G20
–2 kPa
(20 mbar)
Factory setting for type of
gas and gas connection
pressure
Cat. Unit category

Product description 3
0020230530_01 ecoFIT sustain Operating instructions 9
Information
on the identi-
fication plate
Meaning
Condensing
technology
Efficiency class of the boiler
in accordance with EC Dir-
ective 92/42/EEC
Type: Xx3(x) Permissible flue gas connec-
tions
PMS Maximum water pressure in
heating mode
PMW Maximum water pressure in
hot water handling mode
V/Hz Electrical connection
W Max. electrical power con-
sumption
IP Level of protection
Heating mode
Hot water generation
Pn Nominal heat output range
in heating mode
Pnc Nominal heat output range
in heating mode (condensing
technology)
P Nominal heat output range
in hot water handling mode
Qn Nominal heating load range
in heating mode
Qnw Nominal heating load range
in hot water handling mode
Tmax. Max. flow temperature
NOx NOx class for the product
Code (DSN) Specific product code
Read the instructions.
GC no. Gas council number
3.5 Serial number
The serial number is located on a plastic
plate at the bottom of the front casing.
3.6 CE label
The CE label shows that the products
comply with the basic requirements of the
applicable directives as stated on the iden-
tification plate.
The declaration of conformity can be
viewed at the manufacturer's site.
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

4 Operation
10 Operating instructions ecoFIT sustain 0020230530_01
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
Op-
erator
control
element
Function
–Setting the hot water temperat-
ure
–Cancelling the activation of an
operating mode
–Cancelling a change to a set
value
–Going one selection level
higher
–Setting the heating flow tem-
perature
–Reading the system pressure
–Activating the comfort mode
–Activating the operating mode
–Confirm setting
–Going one selection level lower
+
at the
same
time
–Calling up the menu
or –Reducing or increasing the set
value
–Scrolling through menu entries
The current function of the and but-
tons is shown in the display.
Adjustable values are always displayed as
flashing.
You must always confirm a change to a
value. Only then is the new setting saved.
You can press to cancel a procedure at
any time.
4.2 Basic display
50
The basic display shows the current condi-
tion of the product. If you press a selection
button, the activated function is displayed
in the display.
The functions that are available depend
on whether a controller is connected to the
product.
You can switch back to the basic display
by:
–Pressing to exit the selection levels
–Not pressing any button for longer than
15 minutes.
If there is an error message present, the
basic displays switches to the error mes-
sage.
4.3 Adjustment and display levels
The product has two adjustment and
display levels.
The end user level contains information
and setting options that you require as the
end user.
The installer level is reserved for the com-
petent person. It is protected by a code.
Only competent persons may change any
settings in the installer level.

Operation 4
0020230530_01 ecoFIT sustain Operating instructions 11
4.4 Cabinet-type casing
Enclosing the product in cabinet-type cas-
ing requires compliance with the applic-
able design instructions.
If you require cabinet-type casing for your
product, consult a heating specialist com-
pany. Never, under any circumstances,
enclose the product yourself.
4.5 Opening the isolator devices
1. Ask the competent person who in-
stalled the product to explain to you
where these isolator devices are loc-
ated and how to handle them.
2. Open the gas isolator cock fully.
3. Open the service valves in the heating
installation's flow and return.
4. Open the cold water stop valve.
4.6 Starting up the product
▶Only start up the product once the cas-
ing has been completely closed.
4.7 Switching on the product
▶Switch on the product via the main
switch installed on-site.
4.8 Setting the heating flow
temperature
1. Press ( ).
◁The target value of the heating flow
temperature appears on the display.
Note
The competent person may
have adjusted the maximum
possible temperature.
Conditions: No controller connected
▶Use or to set the required heating
flow temperature.
▶Confirm by pressing .
Conditions: Controller connected
▶Set the maximum possible heating flow
temperature on the product.
▶Confirm by pressing .
▶Set the required heating flow temperat-
ure on the controller (→Controller oper-
ating instructions).
4.9 Setting the hot water
temperature
Warning.
Risk of being scalded by hot
water.
To protect against Legionella,
the hot water can be heated up
to above 60 °C at pre-defined
times.
▶Have a competent person
inform you about the meas-
ures that should be taken to
protect against Legionella in
your system.
1. Press ( ).
◁The set hot water temperature
flashes in the display.
Conditions: No controller connected
▶Change the hot water temperature by
pressing or .
▶Confirm by pressing .
Conditions: Controller connected
▶Use to set the maximum possible hot
water temperature on the product.
▶Confirm by pressing .
▶Set the required hot water temperature
on the controller (→Controller operating
instructions).

4 Operation
12 Operating instructions ecoFIT sustain 0020230530_01
4.10 Switching Comfort mode on
and off
Note
Comfort mode immediately sup-
plies hot water at the required tem-
perature, without you having to
wait for the water to heat up.
1. Press ( ).
2. Press ( ).
◁Comf. on or Comf. off are shown
flashing in the display.
3. Activate or deactivate Comfort mode
by pressing or .
4. Press to confirm this change.
◁When you have activated Comfort
mode, the symbol appears in the
basic display. When you have deac-
tivated Comfort mode, the " " sym-
bol goes out in the basic display.
4.11 Switching off the product's
functions
4.11.1 Switching off heating mode
(Summer mode)
1. To switch off heating mode without
switching off the hot water generation,
press ( ).
◁The value of the heating flow tem-
perature appears in the display.
2. Use the button to set the heating
flow temperature to Off.
3. Confirm by pressing .
◁Heating mode is switched off.
◁The symbol appears in the
display.
4.12 Guaranteeing the correct
filling pressure of the heating
system
4.12.1 Checking the filling pressure
of the heating installation
Note
To ensure that the heating installa-
tion operates smoothly, the filling
pressure when the heating install-
ation is cold must be between
0.10 MPa and 0.20 MPa (1.0 bar
and 2.0 bar) or lie between the
two dashed lines in the bar graph
display.
If the heating installation extends
over several storeys, a higher filling
pressure may be required for the
heating installation. Ask a compet-
ent person for details.
In addition, the symbol appears
after approx. one minute.
If the filling pressure in the heating
installation falls below 0.05 MPa
(0.5 bar), then the product switches
off. The display alternates between
the fault message F.22 and the
current filling pressure.
1. Press twice.
◁The values for the current filling
pressure and for the minimum and
maximum filling pressures appear in
the display.
2. Check the filling pressure in the
display.
1/2
System pressure: 0.10 … 0.20 MPa
(1.00 … 2.00 bar)
The filling pressure is in the intended
pressure range.
2/2
Filling pressure: < 0.08 MPa
(< 0.80 bar)

Operation 4
0020230530_01 ecoFIT sustain Operating instructions 13
▶Fill the heating installation.
(→Page 13)
◁If you have topped up the install-
ation with sufficient heating wa-
ter, the display automatically dis-
appears after 20 seconds.
4.12.2 Filling 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 install-
ation with suitable heating
water.
1. Ask a competent person where the
filling cock is located.
2. Connect the filling tap to a heating wa-
ter supply in the way you were told by
the competent person.
3. Open all radiator valves (thermostatic
radiator valves) of the heating installa-
tion.
4. Open the heating water supply.
5. Turn the filling cock on slowly and al-
low water to flow in until the required
filling pressure has been reached.
6. Close the heating water supply.
7. Purge all radiators.
8. Check the filling pressure in the
display.
9. Top up with more water if necessary.
10. Close the filling cock.
11. Return to the basic display.
(→Page 10)
4.13 Protecting the heating
installation against frost
4.13.1 Frost protection function
Caution.
Risk of material damage due
to frost.
The frost protection function
cannot guarantee flow through
the entire heating installation,
which means that parts of the
heating installation may freeze
and therefore become dam-
aged.
▶During a period of frost, en-
sure that the heating installa-
tion remains in operation and
that all rooms are sufficiently
heated, even when you are
away.
Note
To keep the frost protection
devices active, you should switch
your product on and off using the
controller, if one is provided.
If the heating flow temperature falls be-
low 5 °C when the on/off button is on, the
product comes into operation and heats
the circulating water to approx. 30 °C on
both the heating side and the hot water
side (if available).
4.13.2 Draining the heating
installation
When the unit is switched off for an exten-
ded period, frost protection can be guar-
anteed by completely draining the heating
installation and the product.
▶Consult a competent person about this.

5 Troubleshooting
14 Operating instructions ecoFIT sustain 0020230530_01
4.14 Switching the product to
standby mode
▶Press the fault clearance key for less
than three seconds.
◁The display shows OFF and goes
out.
◁The product is now in standby mode.
◁The product's frost protection func-
tion is activated.
◁The main power supply is not inter-
rupted. The product continues to be
supplied with power.
5 Troubleshooting
5.1 Detecting and rectifying faults
▶If faults occur, proceed in accordance
with the table in the appendix.
Troubleshooting (→Page 16)
▶If the fault cannot be eliminated using
the specified measures or if fault mes-
sages (F.xx) occur, contact a compet-
ent person.
5.2 Calling up (Live monitor)
status codes
▶Press and at the same time.
Status codes –Overview (→Page 16)
◁The current operating status (status
code) is shown on the display.
6 Care and maintenance
6.1 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.
6.2 Caring for the product
Caution.
Risk of material damage
caused by unsuitable clean-
ing agents.
▶Do not use sprays, scouring
agents, detergents, solvents
or cleaning agents that con-
tain chlorine.
▶Clean the casing with a damp cloth and
a little solvent-free soap.
6.3 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.
6.4 Checking the condensate
drain pipework and tundish
The condensate drain pipework and tun-
dish must always be penetrable.
▶Regularly check the condensate drain
pipework and tundish for faults and,
particularly, for blockages.
You must not be able to see or feel any
obstructions in the condensate drain pipe-
work and tundish.
▶If you notice a fault, have it rectified by
a competent person.

Decommissioning 7
0020230530_01 ecoFIT sustain Operating instructions 15
7 Decommissioning
7.1 Temporarily decommissioning
the product
Caution.
Risk of material damage due
to frost.
The frost protection and mon-
itoring devices are only active
while the unit is connected to
the power mains and switched
on via the on/off button, and
when the gas isolator cock is
open.
▶Temporarily decommission
the product only if no frost is
expected.
▶Temporarily decommission the product
only if no frost is expected.
▶Switch off the product via the main
switch installed on-site.
◁The display goes out.
▶When decommissioning the product
for a prolonged period (e.g. holiday),
close the gas isolator cock and also, for
combination products, the cold water
stop valve.
7.2 Permanently
decommissioning the product
▶Have a competent person permanently
decommission the product.
8 Recycling and disposal
▶The competent person who installed
your product is responsible for the dis-
posal of the packaging.
If the product is identified with this
symbol:
▶In this case, do not dispose of the
product with the household waste.
▶Instead, hand in the product to a collec-
tion centre for old electrical or electronic
appliances.
If the product contains batteries that
are marked with this symbol, these bat-
teries may contain substances that are
hazardous to human health and the envir-
onment.
▶In this case, dispose of the batteries at
a collection point for batteries.
9 Guarantee and customer
service
9.1 Guarantee
For information on the manufacturer's
guarantee, you can write to the contact
address that is provided on the back page.
9.2 Customer service
To ensure regular servicing, it is strongly
recommended that arrangements are
made for a Maintenance Agreement.
Please contact Vaillant Service Solutions
for further details:
Telephone: [phone]

Appendix
16 Operating instructions ecoFIT sustain 0020230530_01
Appendix
A Status codes –Overview
Status codes that are not listed here can be viewed in the installation instructions.
Status
code
Parameter Meaning
Displays in heating mode
S.00 Heating: No heat demand Heating: No heat demand
S.02 Heating mode: Pump pre-run Heating mode: Pump pre-run
S.03 Heating mode: Ignition Heating mode: Ignition
S.04 Heating mode: Burner on Heating mode: Burner on
S.06 Heating mode: Fan overrun Heating mode: Fan overrun
S.07 Heating mode: Pump overrun Heating mode: Pump overrun
S.08 Heating mode: Anti-cycling time Heating, remaining anti-cycling time xx
mins
Displays in hot water handling mode
S.10 DHW demand Hot water requirement via flow sensor
S.14 DHW mode: Burner on DHW mode: Burner on
Displays in Comfort mode with warm start or hot water handling mode with cylinder
S.20 DHW demand Hot water requirement
S.22 DHW mode: Pump pre-run DHW mode: Pump pre-run
S.24 DHW mode: Burner on DHW mode: Burner on
Others
S.31 No heat demand: Summer mode Summer mode active
S.34 Heating mode: Frost protection Frost protection mode, frost protection
S.46 Waiting time: Measuring program Comfort protection mode, flame loss at
minimum load
B Troubleshooting
Fault Cause Measure
Product does not
start up:
–No hot water
–Heating re-
mains 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 dis-
connected.
Check the fuse in the building.
The product switches on automat-
ically when the power is restored.
The product is switched off. Switch on the product (→"Switch-
ing on the product" section).
The heating flow temperature is set
too low or to the Heating off position,
and/or the hot water temperature is set
too low.
Set the heating flow temperat-
ure and hot water temperature (→
"Setting the heating flow temper-
ature" section/→"Setting the hot
water temperature" section).

Appendix
0020230530_01 ecoFIT sustain Operating instructions 17
Fault Cause Measure
Product does not
start up:
–No hot water
–Heating re-
mains cold
The system pressure is insufficient.
Low water pressure in the heating in-
stallation (fault message: F.22).
Fill the heating installation (→
"Filling the heating installation"
section).
There is air in the heating installation. Have your competent person
purge the heating installation.
After three unsuccessful attempts to
ignite the flame, the product switches to
fault mode (fault message: F.28).
Press the fault clearance key for
one second. The product makes
another attempt to ignite the
flame.
If you have been unable to elim-
inate the ignition fault after three
fault clearance attempts, consult a
competent person.
Hot water gener-
ation functioning
correctly; heating
does not start up.
The external controller is not set cor-
rectly.
Set the external controller cor-
rectly (→Controller operating in-
structions).

0020230530_01 10.10.2016
supplier
Vaillant Ltd.
Nottingham Road Belper Derbyshire DE56 1JT
Telephone [phone]
[email protected] www.vaillant.co.uk
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