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).

0020291544_03 Operating instructions 11
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 compet-
ent person is a prerequisite for ensuring that the product is
permanently 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 or the product is in restricted mode
(comfort protection). The product is not in fault mode; it
continues to operate.
▶Consult a competent person.
Condition:Lhm. 37 is displayed
The product is in Comfort protection mode. The product has
detected a permanent fault and continues to run with restric-
ted comfort.
5.4 Checking the filling pressure of the heating
installation
Note
To avoid operating the installation with insufficient
water volume and to prevent possible damage
associated with this, the product is fitted with a
pressure sensor and a digital pressure display.
To ensure that the heating installation operates
properly, the filling pressure must be between 0.1
MPa and 0.15 MPa (1.0 bar and 1.5 bar) when the
heating installation condition is cold.
If the heating installation extends over several
storeys, a higher filling pressure may be required
for the heating installation. Ask a competent per-
son for details.
Note
If the pressure falls below 0.07 MPa (0.7 bar),
message M32 appears.
If the pressure rises above 0.07 MPa (0.7 bar),
message M32 goes out.
In addition, the symbol is displayed after ap-
prox. one minute.
If the filling pressure of the heating installation
falls below 0.05 MPa (0.5 bar) for longer than one
minute, fault message F.22 and the current filling
pressure appear alternately in the display.
If the blocking time has elapsed or if the filling
pressure of the heating installation rises above
0.05 MPa (0.5 bar), fault message F.22 goes out.
1. Use Menu →Live Monitor Water pressure to display
the filling pressure of the heating installation.
2. If the pressure drops frequently, identify and eliminate
the reason for the pressure loss of heating water. In-
form a competent person of this.
6 Troubleshooting
6.1 Reading fault messages
Fault messages have priority over all other displays and are
shown on the display instead of the basic display. If several
faults occur at the same time, these are displayed alternately
for two seconds each.
Depending on the type of fault, the system can work in limp
home mode in order to maintain the heating mode or do-
mestic hot water generation.
F.723 Building circuit: Pressure too low
If the filling pressure falls below the minimum pressure, the
heat pump will be switched off automatically.
▶Inform your competent person so that he can top up the
heating water.
F.1120 Immersion heater: Phase failure
The product has an internal circuit breaker which switches
off the heat pump in the event of short circuits or the failure
of one (product with 230 V power supply) or several (product
with 400 V power supply) current-carrying phases.
If the electric back-up heater is defective, the anti-legionella
function is not always guaranteed.
▶Inform your competent person so that they can eliminate
the fault and reset the internal circuit breaker.
6.2 Detecting and eliminating faults
▶If problems occur whilst operating the product, you can
carry out certain checks with the aid of the table.
Troubleshooting (→Appendix A)
▶If the product is not functioning correctly, even though
you have checked the points listed in the table, contact a
competent person.
7 Decommissioning
7.1 Temporarily decommissioning the product
▶Use the partition that is installed on-site (e.g. fuses
or power switches) to disconnect the product from the
power supply.

12 Operating instructions 0020291544_03
7.2 Permanently decommissioning the product
▶Have a competent person permanently decommission
and dispose of the product.
8 Recycling and disposal
Disposing of the packaging
▶The competent person who installed your product is re-
sponsible for the disposal 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 collection centre for
waste electrical or electronic 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. Other-
wise, the batteries are disposed of together with the
product.
▶In accordance with the legal regulations, used batteries
must be returned since batteries may contain substances
that are harmful to health and the environment.
9 Guarantee and customer service
9.1 Guarantee
Vaillant provides a full parts and labour guarantee for this
appliance for the duration as shown on the enclosed re-
gistration card which must be fully completed and returned
within 30 days of installation. All appliances must be installed
by a suitably competent person fully conversant and in ac-
cordance with all current regulations applicable to the ap-
pliance type installation. In the case of gas appliances the
Gas Safety (Installation and Use) Regulations 1998, and the
manufacturer’s instructions. In the UK competent persons
approved at the time by the Health and Safety Executive un-
dertake the work in compliance with safe and satisfactory
standards. Installers should also be fully conversant with and
competent with all necessary electrical and building regula-
tions that may apply to the installation.
In addition all unvented domestic hot water cylinders must
be installed by a competent person to the prevailing build-
ing regulations at the time of installation (G3). All appliances
shall be fully commissioned in accordance with our installa-
tion manual and Benchmark commissioning check list (this
will be included within the installation manual). These must
be signed and given to the user for safe keeping during the
hand over process. Installers should also at this time advise
the user of the annual servicing requirements and advise of
appropriate service agreement.
Terms and conditions do apply to the guarantee, details of
which can be found on the registration card included with this
appliance. In order to qualify for guarantee after one year the
appliance must be serviced in accordance with our installa-
tion manual servicing instructions. The benchmark service
history should be completed. Note - all costs associated with
this service are excluded from this guarantee.
Failure to install and commission this appliance in compli-
ance with the manufacturer’s instructions will invalidate the
guarantee (this does not affect the customer’s statutory
rights).
9.2 Customer service
The contact details for our customer service are provided on
the back page or on our website.

0020291544_03 Operating instructions 13
Appendix
A Troubleshooting
Problem Possible cause Remedy
No domestic hot water, heat-
ing remains cold; product
does not start up
Building power supply switched off Switch on building power supply
Domestic hot water or heating set to "off"/domestic
hot water temperature or target temperature set too
low
Ensure that domestic hot water mode and/or
heating mode is activated in the system control.
Set the domestic hot water temperature in the
system control to the required value.
Air in the heating installation Purging the radiators
If the problem occurs again: Inform the compet-
ent person
Domestic hot water mode
without any problems; heat-
ing does not start
No heat requirement via the control Check the timer programme on the control and
correct if necessary
Check the room temperature and, if required,
correct the target room temperature (→Control
operating instructions)
B Overview of the end user level
Setting level Values Unit Increment, select Factory setting Setting
Min. Max.
Basic display →Right-hand selection button
Room temperature setpoint * Current value ℃
Manual cooling demand*
Basic display →Left-hand selection button
Domestic hot water cylinder tar-
get temperature*
Current value ℃
Actual domestic hot water cylin-
der temperature
Current value ℃
Yield indicator →
Energy yield: Day, Heating Cumulative value kWh
Energy yield: Day, Domestic hot
water
Cumulative value kWh
Energy yield: Day, Cooling Cumulative value kWh
Energy yield: Month, Heating Cumulative value kWh
Working figure: Month, Heating Cumulative value
Energy yield: Total, Heating Cumulative value kWh
Working figure: Total, Heating Cumulative value
Energy yield: Month, Cooling Cumulative value kWh
SEER, month, cooling Cumulative value
Energy yield: Total, Cooling Cumulative value kWh
SEER, total, cooling Cumulative value
Energy yield: Month, Domestic
hot water
Cumulative value kWh
Working figure: Month, Domestic
hot water
Cumulative value
Energy yield: Total, Domestic
hot water
Cumulative value kWh
Working figure: Total, Domestic
hot water
Cumulative value
Total energy consumption Cumulative value kWh
Live Monitor →
Current status message(s) Current value
Building circuit water pressure Current value bar
*If no system control is installed, the menu item is displayed in the product's control panel.

14 Operating instructions 0020291544_03
Setting level Values Unit Increment, select Factory setting Setting
Min. Max.
Building circuit flow rate Current value l/h
Compressor anti-cycling time Current value min
Immersion heater anti-cycling
time
Current value min
Target flow temp. Current value ℃
Current flow temp. Current value ℃
Energy integral Current value °min
Cooling capacity Current value kW
Electrical power consumption Current value kW Total power consump-
tion of the heat pump
without any external
components connec-
ted (as supplied).
Compressor modulation Current value %
Air inlet temperature Current value ℃
Immersion heater power Current value kW
External current anode status Current value Anode not con-
nected
Outdoor temperature Current value ℃
Information →
Contact details Phone number
Serial number Permanent value
Operating hours total Cumulative value h
Hours heating Cumulative value h
DHW operating hours Cumulative value h
Cooling op. hours Cumulative value h
Default settings →
Language Current language Languages available for
selection
02 English
Display contrast Current value 1 25
15 40
Resets →
No sub-items available
*If no system control is installed, the menu item is displayed in the product's control panel.

0020291544_03 Installation and maintenance instructions 15
Installation and maintenance
instructions
Contents
1 Safety .................................................................. 17
1.1 Intended use ........................................................ 17
1.2 General safety information .................................. 17
1.3 Regulations (directives, laws, standards) ............ 18
2 Notes on the documentation ............................ 19
2.1 Further information .............................................. 19
3 Product description........................................... 19
3.1 Heat pump system............................................... 19
3.2 Safety devices ..................................................... 19
3.3 Product overview ................................................. 20
3.4 Serial number ...................................................... 21
3.5 Information on the data plate............................... 21
3.6 Connection symbols ............................................ 21
3.7 CE marking .......................................................... 21
3.8 Cooling mode....................................................... 21
3.9 Display of the energy consumption, energy
yields and efficiencies.......................................... 21
4 Set-up.................................................................. 22
4.1 Unpacking the product......................................... 22
4.2 Checking the scope of delivery............................ 22
4.3 Selecting the installation site ............................... 22
4.4 Permissible height difference between the
outdoor unit and the indoor unit........................... 22
4.5 Dimensions .......................................................... 22
4.6 Minimum clearances and installation
clearances ........................................................... 23
4.7 Wall-mounting the product................................... 23
4.8 Removing the front casing................................... 24
5 Hydraulics installation ...................................... 24
5.1 Carrying out the installation preparations ............ 24
5.2 Connecting the heat pump to the indoor unit....... 24
5.3 Connecting the domestic hot water cylinder's
heating flow and heating return ........................... 24
5.4 Connecting the building circuit............................. 25
5.5 Installing the drain hose on the expansion
relief valve............................................................ 25
6 Electrical installation......................................... 25
6.1 Preparing the electrical installation...................... 25
6.2 Requirements for the quality of the mains
voltage ................................................................. 25
6.3 Electrical partition ................................................ 26
6.4 Installing components for the energy supply
company lockout function .................................... 26
6.5 Opening the power supply PCB's electronics
box ....................................................................... 26
6.6 Routing the cables in the product ........................ 26
6.7 Establishing the power supply, 1~/230V.............. 27
6.8 Establishing the power supply, 3~/400V.............. 28
6.9 Installing the system control in the electronics
box ....................................................................... 29
6.10 Requirements for the eBUS line .......................... 29
6.11 Opening the control PCB's electronics box ......... 29
6.12 Routing the cables in the electronics box ............ 29
6.13 Carrying out the wiring......................................... 30
6.14 Connecting the circulation pump ......................... 30
6.15 Connecting a limit thermostat for the
underfloor heating................................................ 30
6.16 Actuating a circulation pump with an eBUS
control .................................................................. 30
6.17 Connecting the outdoor temperature sensor ....... 31
6.18 Connecting the domestic hot water cylinder's
temperature sensor.............................................. 31
6.19 Connecting the VR 70/VR 71 mixer module........ 31
6.20 Connecting cascades .......................................... 31
6.21 Closing the electronics box for the power
supply PCB .......................................................... 31
6.22 Checking the electrical installation ...................... 31
7 Operation............................................................ 31
7.1 Operating concept of the product ........................ 31
8 Start-up ............................................................... 31
8.1 Prioritising diverter valve, setting the heating
circuit/cylinder charging ....................................... 31
8.2 Checking and treating the heating water/filling
and supplementary water .................................... 32
8.3 Filling and purging the heating installation .......... 32
8.4 Purging ................................................................ 33
8.5 Switching on the product ..................................... 33
8.6 Running the installation assistants ...................... 33
8.7 Menu functions without the optional system
control .................................................................. 34
8.8 Energy balance control........................................ 34
8.9 Compressor hysteresis........................................ 34
8.10 Enabling the electric back-up heater ................... 34
8.11 Setting the anti-legionella function....................... 34
8.12 Purging ................................................................ 34
8.13 Calling up the installer level................................. 35
8.14 Restarting the installation assistants ................... 35
8.15 Checking the configuration .................................. 35
8.16 Calling up statistics.............................................. 35
8.17 Floor drying.......................................................... 35
8.18 Activating cooling mode....................................... 36
8.19 Starting up the optional system control ............... 36
8.20 Displaying the filling pressure in the building
circuit ................................................................... 36
8.21 Checking function and leak-tightness.................. 36
9 Adapting the unit to the heating
installation.......................................................... 36
9.1 Configuring the heating installation ..................... 36
9.2 Total pressure loss in the product, heating
circuit and domestic hot water ............................. 36
9.3 Setting the flow temperature in heating mode
(with no control connected) ................................. 36
9.4 Instructing the end user ....................................... 36
10 Troubleshooting ................................................ 37
10.1 Contacting your service partner........................... 37
10.2 Displaying the Live Monitor (current product
status) .................................................................. 37
10.3 Checking fault codes ........................................... 37

16 Installation and maintenance instructions 0020291544_03
10.4 Querying the fault memory .................................. 37
10.5 Resetting the fault memory.................................. 37
10.6 Using the function menu...................................... 37
10.7 Using check programmes.................................... 37
10.8 Carrying out the actuator test .............................. 37
10.9 Resetting parameters to factory settings ............. 37
10.10 Preparing the repair work .................................... 37
10.11 Safety cut-out....................................................... 38
11 Inspection and maintenance ............................ 38
11.1 Inspection and maintenance information............. 38
11.2 Procuring spare parts .......................................... 38
11.3 Checking maintenance messages....................... 38
11.4 Observing inspection and maintenance
intervals ............................................................... 39
11.5 Preparing for inspection and maintenance .......... 39
11.6 Checking the pre-charge pressure of the
expansion vessel ................................................. 39
11.7 Checking the high-pressure switch-off ................ 39
11.8 Checking and correcting the filling pressure of
the heating installation......................................... 39
11.9 Completing inspection and maintenance............. 39
12 Draining .............................................................. 39
12.1 Draining the product's heating circuit................... 39
13 Decommissioning.............................................. 40
13.1 Temporarily decommissioning the product.......... 40
13.2 Permanently decommissioning the product......... 40
14 Recycling and disposal..................................... 40
14.1 Disposing of the product and accessories........... 40
15 Customer service............................................... 40
Appendix ............................................................................ 41
A Functional diagram............................................ 41
B Wiring diagram................................................... 42
C Basic connection diagram for the energy
supply company lockout, shutdown via
connection S21 .................................................. 43
D Basic connection diagram for the energy
supply company lockout, shutdown via
partition .............................................................. 44
E Installer level overview...................................... 45
F Status codes ...................................................... 49
G Maintenance messages .................................... 51
H Comfort protection mode.................................. 51
I 5.4 kW back-up heater at 230 V and at
400 V ................................................................... 52
J Inspection and maintenance work................... 52
K Characteristic values for the internal
temperature sensors, hydraulic circuit ........... 52
L Characteristic values for the VR10
internal temperature sensors, cylinder
temperature ........................................................ 53
M Characteristic values for the VRC DCF
outdoor temperature sensor............................. 54
N Technical data.................................................... 54
Index ................................................................................... 56

0020291544_03 Installation and maintenance instructions 17
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.
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
–observance of accompanying operating,
installation and maintenance instructions
for the product and any other system com-
ponents
–installing and setting up the product in ac-
cordance with the product and system ap-
proval
–compliance with all inspection and main-
tenance conditions listed in the instruc-
tions.
Intended use also covers installation in ac-
cordance with the IP code.
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 Risk caused by inadequate
qualifications
The following work must only be carried out
by competent persons who are sufficiently
qualified to do so:
–Set-up
–Dismantling
–Installation
–Start-up
–Inspection and maintenance
–Repair
–Decommissioning
▶Proceed in accordance with current tech-
nology.
1.2.2 Risk of death from electric shock
There is a risk of death from electric shock if
you touch live components.
Before commencing work on the product:
▶Disconnect the product from the power
supply by switching off all power supplies
at all poles (electrical partition in over-
voltage category III for full partition, e.g.
fuse or circuit breaker).
▶Secure against being switched back on
again.
▶Wait for at least 3 minutes until the capa-
citors have discharged.
▶Check that there is no voltage.
1.2.3 Risk of death due to lack of safety
devices
The basic diagrams included in this docu-
ment do not show all safety devices required
for correct installation.
▶Install the necessary safety devices in the
installation.
▶Observe the applicable national and inter-
national laws, standards and directives.
1.2.4 Risk of burns or scalding caused by
hot components
▶Only carry out work on these components
once they have cooled down.
1.2.5 Risk of being scalded by hot potable
water
There is a risk of scalding at the domestic
hot water draw-off points if the domestic hot
water temperatures are greater than 50 °C.
Young children and elderly persons are par-
ticularly at risk, even at lower temperatures.
▶Select a temperature at which nobody can
be harmed.
▶Inform the end user about the risk of scald-
ing when the Anti-legionella function is
switched on.

18 Installation and maintenance instructions 0020291544_03
1.2.6 Risk of injury due to the heavy weight
of the product
▶Make sure that the product is transported
by at least two people.
1.2.7 Risk of material damage due to an
unsuitable installation surface
The installation surface must be even and
have sufficient load-bearing capacity to sup-
port the operating weight of the product. An
uneven installation surface may cause leaks
in the product.
There is a risk of death if the connections are
subject to leaks.
▶Make sure that the product is positioned
flush against the installation surface.
▶Ensure that the installation surface has
sufficient load-bearing capacity to bear the
operating weight of the product.
1.2.8 Risk of material damage due to
malfunctioning
Not rectifying faults, changing the safety
devices and failing to carry out maintenance
can cause malfunctioning and pose safety
risks during operation.
▶Ensure that the heating installation is in a
technically perfect condition.
▶Ensure that no safety or monitoring
devices have been removed, bridged or
disabled.
▶Immediately eliminate any faults and dam-
age that may affect safety.
1.2.9 Risk of material damage due to
additional elements in the heating
water
Unsuitable antifreeze and corrosion inhibitors
may damage seals and other components
of the heating circuit, and may therefore also
cause water leaks.
▶Only add approved antifreeze and corro-
sion inhibitors to the heating water.
1.2.10 Risk of material damage caused by
frost
▶Do not install the product in rooms prone
to frost.
1.2.11 Risk of material damage caused by
using an unsuitable tool
▶Use the correct tool.
1.3 Regulations (directives, laws,
standards)
▶Observe the national regulations, stand-
ards, directives, ordinances and laws.

0020291544_03 Installation and maintenance instructions 19
2 Notes on the documentation
▶Always observe all the operating and installation instruc-
tions included with the system components.
▶Pass these instructions and all other applicable docu-
ments on to the end user.
These instructions apply only to:
Product
VWZ MEH 97/6
Product
VIH QW 190/6 E GB
2.1 Further information
▶Scan the displayed code using your smartphone in order
to view further information about the installation.
◁You are guided to installation videos.
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 Heat pump, outdoor unit
2 eBUS line
3 System control
(optional)
4 Heat pump, indoor unit
5 Monovalent domestic
hot water cylinder
6 Heating circuit
3.2 Safety devices
3.2.1 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.
3.2.2 Low-water pressure protection
This function continuously monitors the heating water pres-
sure in order to prevent a possible loss of heating water. If
the water pressure falls below the minimum pressure, an
analogue pressure sensor switches the product off and, if
available, switches other modules to standby mode. If the
water pressure reaches the operating pressure, the pressure
sensor switches the product back on.
If the heating water pressure falls below ≤0.1 MPa (1 bar),
a maintenance message appears below the display of the
minimum operating pressure.
–Min. heating circuit pressure: ≥0.05 MPa (≥0.50 bar)
–Min. heating circuit operating pressure: ≥0.07 MPa
(≥0.70 bar)
3.2.3 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 ℃

20 Installation and maintenance instructions 0020291544_03
3.3 Product overview
3.3.1 Product design
6
4
5
1
2
3
1 Unit mounting bracket
2 Expansion vessel
3 Hydraulic block
4 Electronics box with
control PCB
5 Control for the indoor
unit
6 Electronics box with
power supply PCB
3.3.2 Design of the hydraulic block
8
9
10
1
2
3456
7
1 Manometer
2 Expansion relief valve
3 Building circuit return
4 Building circuit flow
5 Domestic hot water
cylinder return
6 Domestic hot water
cylinder flow
7 Prioritising diverter
valve (heating cir-
cuit/cylinder charging)
8 Electric back-up heater
9 Safety cut-out
10 Automatic air vent
3.3.3 Underside of the product
1
6
5
4
3
2
7
1 Drain for expansion
relief valve
2 Building circuit return
3 Building circuit flow
4 Domestic hot water
cylinder flow
5 Domestic hot water
cylinder return
6 Heating return, to the
heat pump
7 Heating flow, from the
heat pump