Vaillant VWZ MEH 97/6 User manual

en Operating instructions
en Installation and maintenance instructions
Hydraulic station
VWZ MEH 97/6
0020291544_03 - 23.01.2023

2
en Operating instructions ....................................... 3
en Installation and maintenance instructions...... 15

0020291544_03 Operating instructions 3
Operating instructions
Contents
1 Safety .................................................................... 4
1.1 Intended use .......................................................... 4
1.2 General safety information .................................... 4
2 Notes on the documentation .............................. 6
3 Product description............................................. 6
3.1 Heat pump system................................................. 6
3.2 Design of the product............................................. 6
3.3 Control elements.................................................... 6
3.4 Control panel ......................................................... 7
3.5 Description of the symbols .................................... 7
3.6 Functional description of buttons........................... 7
3.7 Type designation and serial number ..................... 8
3.8 CE marking ............................................................ 8
3.9 Safety devices ....................................................... 8
4 Operation.............................................................. 8
4.1 Basic display.......................................................... 8
4.2 Operating concept ................................................. 8
4.3 Menu display.......................................................... 8
4.4 Starting up the product .......................................... 9
4.5 Setting the heating flow temperature................... 10
4.6 Setting the domestic hot water temperature........ 10
4.7 Switching off the product's functions ................... 10
5 Care and maintenance ...................................... 11
5.1 Caring for the product.......................................... 11
5.2 Maintenance ........................................................ 11
5.3 Reading maintenance messages ........................ 11
5.4 Checking the filling pressure of the heating
installation............................................................ 11
6 Troubleshooting ................................................ 11
6.1 Reading fault messages ...................................... 11
6.2 Detecting and eliminating faults........................... 11
7 Decommissioning.............................................. 11
7.1 Temporarily decommissioning the product.......... 11
7.2 Permanently decommissioning the product......... 12
8 Recycling and disposal..................................... 12
9 Guarantee and customer service..................... 12
9.1 Guarantee............................................................ 12
9.2 Customer service................................................. 12
Appendix ............................................................................ 13
A Troubleshooting ................................................ 13
B Overview of the end user level......................... 13

4Operating instructions 0020291544_03
1 Safety
1.1 Intended use
There is a risk of injury or death to the user or
others, or of damage to the product and other
property in the event of improper use or use
for which it is not intended.
This product is a system component for con-
trolling the heating circuits and domestic hot
water generation in conjunction with a heat
pump using a system control.
Intended use includes the following:
–observance of the operating instructions
included for the product and any other
installation components
–compliance with all inspection and main-
tenance conditions listed in the instruc-
tions.
The product is intended exclusively for do-
mestic use.
The intended use only allows for these
product combinations:
Outdoor unit Indoor unit
VWL ..5/6 A .. VIH QW 190/6...
VWZ MEH 97/6
This product can be used by children aged
from 8 years and above and persons with
reduced physical, sensory or mental capabil-
ities or lack of experience and knowledge if
they have been given supervision or instruc-
tion concerning use of the product in a safe
way and understand the hazards involved.
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 specified in these
instructions, or use beyond that specified in
this document, shall be considered improper
use. Any direct commercial or industrial use
is also deemed to be improper.
Caution.
Improper use of any kind is prohibited.
1.2 General safety information
1.2.1 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 applicable documents, par-
ticularly the "Safety" section and the warn-
ings.
▶Only carry out the activities for which in-
structions are provided in these operating
instructions.
1.2.2 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 tamper-
proof seals on components.
▶Do not make any changes:
–The product itself
–The water and electricity supply lines
–to the expansion relief valve
–to the drain pipework
–to constructional conditions that may
affect the operational reliability of the
product
1.2.3 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
eliminated by a competent person.
▶Adhere to the maintenance intervals spe-
cified.
1.2.4 Risk of material damage caused by
frost
▶Ensure that the heating installation always
remains in operation during freezing con-
ditions and that all rooms are sufficiently
heated.
▶If you cannot ensure the operation, have a
competent person drain the heating install-
ation.

0020291544_03 Operating instructions 5
1.2.5 Benchmark
Vaillant is a licensed member of the Bench-
mark Scheme which aims to improve the
standards of installation and commissioning
of domestic heating and hot water systems in
the UK and to encourage 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 in-
structions supplied with the product and
that you have signed it to say that you
have received a full and clear explana-
tion of its operation. The installer is leg-
ally required to complete a commissioning
checklist as a means of complying with the
appropriate Building 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 Certificate will then
be issued to the customer who should, on
receipt, write the Notification Number on the
Benchmark Checklist.
This product should be serviced regularly to
optimise its safety, efficiency and perform-
ance. The service engineer should complete
the relevant Service Record on the Bench-
mark Checklist after each service.
The Benchmark Checklist will be required in
the event of any warranty.

6Operating instructions 0020291544_03
2 Notes on the documentation
▶Always observe all operating instructions that are en-
closed with the installation components.
▶Store these instructions and all other applicable docu-
ments for further use.
These instructions apply only to:
Product
VWZ MEH 97/6
Product
VIH QW 190/6 E GB
3 Product description
3.1 Heat pump system
Design of a typical heat pump system with monoblock tech-
nology:
12
4
3
5
6
1 Outdoor unit
2 eBUS line
3 System control
4 Indoor unit
5 Domestic hot water
cylinder
6 Heating circuit
3.2 Design of the product
2
3
1
1 Optional installation site
for the system control
2 Reset button
3 Control elements
3.3 Control elements
reset
120kWh/d
E
4
3 2 1
1 System control (optional
accessory)
2 Reset button
3 Control panel
4 Display

0020291544_03 Operating instructions 7
3.4 Control panel
120kWh/d
E
reset
1
2
3
4
6
7
8
9
5
1 Displays the daily envir-
onmental energy yield
2 Display of the current
assignment of the right-
hand selection button
3 Left- and right-hand
selection buttons
4 and button
5 Reset button, restart the
product
6 Access to the menu for
additional information
7 Display of the current
assignment of the left-
hand selection button
8 Displays the symbols
for the heat pump's
current operating mode
9 Display
3.5 Description of the symbols
If you do not press any buttons within one minute, the light-
ing goes out.
Symbol Meaning Explanation
Compressor
power
–Not filled: Compressor not in
operation
–Partially filled: Compressor in
operation. Partial load mode.
–Fully filled: Compressor in
operation. Full load mode.
Symbol Meaning Explanation
bar
–Without
decoupling
module
–Filling
pressure
in the
building
circuit
(measured
in the
outdoor
unit)
–With decoup-
ling module
–Filling
pressure
in the
building
circuit
(measured
in the
indoor
unit)
The dashed lines show the
permitted range.
–Displayed statically: Filling
pressure in the permitted
range
–Displayed flashing: Filling
pressure outside of the
permitted range
Noise reduction
mode
–Operation with reduced
noise emissions
Electric back-up
heater
–Displayed flashing: Electric
back-up heater in operation
–Displayed together with the
"Heating mode" symbol:
Electric back-up heater
active for heating mode
–Displayed together with
the "Domestic hot water
generation" symbol: Electric
back-up heater active for
domestic hot water mode
eco mode –Energy-saving domestic hot
water mode
Heating mode –Heating mode active
Domestic hot
water generation
–Domestic hot water mode
active
Cooling mode –Cooling mode active
F. X X X
Fault condition –Appears instead of the basic
display, may be an explanat-
ory plain text display
3.6 Functional description of buttons
The two selection buttons are soft keys, meaning that they
can be assigned different functions.
Button Meaning
–Cancelling the change to a set value or
activating an operating mode
–Calling up a higher selection level in the
menu
–Confirming a set value or activating an oper-
ating mode
–Calling up a lower selection level in the
menu
+Calling up the additional functions

8Operating instructions 0020291544_03
Button Meaning
or –Navigating between individual menu items
–Increasing or decreasing the chosen set
value
Adjustable values flash in the display.
You must always confirm a change to a value. Only then is
the new setting saved. You can press to cancel a pro-
cess at any time. If you do not press any buttons for longer
than 15 minutes, the display returns to the basic display.
3.7 Type designation and serial number
The type designation and serial number are on the data
plate.
3.8 CE marking
The CE marking shows that the products comply with the
basic requirements of the applicable directives as stated on
the declaration of conformity.
The declaration of conformity can be viewed at the manufac-
turer's site.
3.9 Safety devices
3.9.1 Frost protection function
The frost protection function for the system is controlled us-
ing the product itself or using the optional system control. If
the system control fails, the product guarantees limited frost
protection for the heating circuit.
At negative outdoor temperatures, there is an increased risk
of the heating water freezing if a heat pump fault occurs, e.g.
due to a power cut or a defective compressor.
3.9.2 Low-water pressure protection
This function continuously monitors the heating water pres-
sure in order to prevent a possible loss of heating water.
3.9.3 Freeze protection
This function prevents the unit's internal heating circuit from
freezing when the heating flow temperature drops below a
certain value.
If the heating flow temperature of the outdoor unit falls below
4 °C, the compressor is switched on in order to increase the
heating flow temperature.
3.9.4 Pump blocking protection
This function prevents the pumps for heating water from
sticking. The pumps, which were out of operation for
23 hours, are switched on for 10–20 seconds, one after the
other.
3.9.5 Safety cut-out (SCO) in the heating circuit
If the temperature in the heating circuit of the internal elec-
tric back-up heater exceeds the maximum temperature, the
safety cut-out shuts down the electric back-up heater as a
securing measure. After it is triggered, the safety cut-out
must be replaced.
–Max. heating circuit temperature: 89 ℃
4 Operation
4.1 Basic display
120kWh/d
E
1
The displays shows the basic display with the current status
of the product. The daily energy yield (1) is displayed in the
centre of the display.
If you press a selection button, the activated function is dis-
played in the display.
As soon as a fault message is present, the basic displays
switches to the fault message.
4.2 Operating concept
The product has two operating levels.
The operating level for the end user shows the most import-
ant information and offers setting options which do not re-
quire any special prior knowledge.
The operating level for the competent person is reserved for
the competent person and is protected by a code.
Overview of the end user level (→Appendix B)
4.3 Menu display
Xxxx
Xxxxxxxxxxx
Xxxx Xxxxxxx
Xxxxxxxxxx
xxxxxx Xxxxxxx
1
4
3
2
1 Scroll bar
2 Current assignment of
the selection buttons
3 Selection level list
entries
4 Selection level
Note
Path details at the start of a section specify how to
access this function, e.g. Menu →Information →
Contact details.

0020291544_03 Operating instructions 9
4.4 Starting up the product
4.4.1 Opening the isolators
1. Ask the competent person who installed the product to
explain to you where these isolators are located and
how to handle them.
2. If installed, open the service valves in the heating in-
stallation's flow and return.
3. Open the cold-water isolation valve.
4.4.2 Switching on the product
Note
The product does not have an on/off switch. The
product is switched on and ready for operation
as soon as it is connected to the power grid. It
can only be switched off using the partition that is
installed on-site, e.g. fuses or circuit breaker in the
utility connection box.
1. Ensure that the product casing has been installed.
2. Switch on the product via the fuses in the utility con-
nection box.
◁The "basic display" is shown in the product's oper-
ating display.
◁The "basic display" may also be shown in the
display for the optional system control.
4.4.3 Adjusting the target cylinder temperature
Danger!
Risk of death from legionella.
Legionella multiply at temperatures below
60 °C.
▶Have a competent person inform you
about the measures that should be taken
to protect against Legionella in your in-
stallation.
▶Do not set any water temperatures below
60 °C without consulting the competent
person first.
Danger!
Risk of death from legionella!
If you decrease the cylinder temperature, the
risk of legionella spreading increases.
▶Activate the anti-legionella times in the
system control and set them.
Depending on the source of the energy obtained from the
environment, target cylinder temperatures of up to 70 °C can
be reached with the compressor. In order to achieve energy-
efficient domestic hot water generation predominantly from
the energy extracted from the environment, the factory set-
ting for the desired domestic hot water temperature must be
adjusted on the optional system control and/or on the heat
pump's control panel.
Condition: System control connected
▶To do this, adjust the target cylinder temperature (De-
sired DHW circuit temperature) to between 50 and
55 °C.
▶Also switch on the electric back-up heater for the do-
mestic hot water generation so that, also at outdoor tem-
peratures below -10 °C and above +30 °C, the required
60 °C can be achieved for the anti-legionella function
time programme.
Condition: No system control connected
▶To do this, set the target cylinder temperature (domestic
hot water target cylinder temp.) to 65 °C.
Note
If no system control is connected, the time
programme for the anti-legionella function is
not available. To still ensure anti-legionella
function, the target cylinder temperature must
therefore be set higher.
▶Also switch on the electric back-up heater for the do-
mestic hot water generation so that, at outdoor temperat-
ures below -10 °C and above +30 °C, the required 60 °C
can also be achieved for the anti-legionella function.
4.4.4 Display of the energy consumption, energy
yields and efficiencies
The product, the system control and the app show approx-
imate values for energy consumption, energy yields and ef-
ficiencies, which are extrapolated based on calculation al-
gorithms.
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 recording of the values only includes the product in the
factory-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 con-
sumers, are not part of the data recording.
Deviations between the determined values and the actual
values may be significant. The determined values are there-
fore not suitable for creating or comparing energy billing, for
example.
When replacing the PCB, the values for energy consump-
tion, energy yields and efficiencies are reset in the heat
pump's control panel.
4.4.5 Displaying the Live Monitor
Menu →Live Monitor
You can use the Live Monitor to view the current status of
the product.
4.4.6 Displaying the building circuit pressure
Menu →Live Monitor→Building circuit pressure

10 Operating instructions 0020291544_03
You can use this function to display the current filling pres-
sure of the heating installation.
4.4.7 Reading the operating statistics
Menu →Information →Heating op. hours
Menu →Information →DHW operating hours
Menu →Information →Cooling op. hours
Menu →Information →Total operating hours
You can use this function to display the operating hours
for heating mode, for domestic hot water mode, for cooling
mode and for overall operation.
4.4.8 Setting the language
1. If you want to set another language, press and hold
and at the same time.
2. Also press the reset button for a short time.
3. Press and hold and until the display shows the
language setting.
4. Select the required language by pressing or .
5. Press (OK) to confirm your selection.
6. Once you have set the correct language, press (OK)
again to confirm this.
4.4.9 Set display contrast
Menu →Basic settings →Display contrast
▶You can set the contrast here.
4.4.10 Serial number and article number
Menu →Information →Serial number
The product's serial number is displayed.
The article number is found in the second line of the serial
number.
4.4.11 Contact details for the competent person
Menu →Information →Contact data Phone number
If the competent person has entered their telephone number
during the installation, you can read it here.
4.5 Setting the heating flow temperature
Condition: No system control connected
▶Press in the basic display.
▶Use or to change the value and confirm this.
Condition: System control connected
▶Set the heating flow temperature on the system control,
→System control operating instructions.
4.6 Setting the domestic hot water temperature
Condition: No system control connected
▶Press in the basic display.
▶Use or to change the value and confirm this.
Condition: System control connected
▶Set the domestic hot water temperature on the system
control, →System control operating instructions.
4.7 Switching off the product's functions
4.7.1 Frost protection function
Caution.
Risk of material damage due to frost.
The frost protection function cannot guaran-
tee circulation through the entire heating in-
stallation. Under certain circumstances, there
is therefore a risk of frost to certain parts of
the heating installation, which may cause
damage.
▶During a period of frost, ensure that the
heating installation remains in operation
and that all rooms are sufficiently heated,
even when you are away.
▶It is strongly recommended that antifreeze
is used for filling those parts of the install-
ation which are at risk of frost.
To ensure that the frost protection devices are permanently
ready for operation, you must leave the system switched on.
Another way to protect the heating installation and the
product from frost for very long switch-off periods is to drain
them completely.
▶Consult a competent person about this.
4.7.2 Switching off heating mode (Summer mode)
Condition: No system control connected
▶Press in the basic display.
▶Use to change the value to zero and confirm this.
Condition: System control connected
▶Switch off heating mode on the system control (summer
mode), →System control operating instructions.
4.7.3 Switching off domestic hot water generation
Condition: No system control connected
▶Press in the basic display.
▶Use to set the value to zero and confirm this.
Condition: System control connected
▶Switch off the domestic hot water generation at the sys-
tem control (→System control operating instructions).