Vaillant VWZ AI, Operating Instructions Manual, Page: 7 / 40

Operation 4
0020291573_00 Heat pump control interface module Operating instructions
5
Symbol Meaning Explanation
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.XXX
Fault condition
–
Appears instead of the basic
display, may be an explanat-
ory plain text display
3.5 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
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.
3.6 Type designation and serial number
The type designation and serial number are on the data plate
on the rear of the housing.
3.7 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.
3.8 Safety devices
3.8.1 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.
3.8.2 Low-water pressure protection
This function continuously monitors the pressure of the heat-
ing water in order to prevent a possible loss of heating water.
3.8.3 Freeze protection
This function prevents the 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.
3.8.4 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.
4 Operation
4.1 Basic display
120
kWh/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.