Function Description Appliance Functions; Heating Mode; Opentherm Controller; Venting Program - Viessmann Vitodens 050-W Installation And Service Instructions Manual

Function description
Appliance functions

Heating mode

Weather-compensated operation:
■
The rooms are heated in accordance with the room
temperature settings.
The control unit determines a set flow temperature
for the heat generator, subject to the outside temper-
ature, the room temperature and the slope/level of
the heating curve.
Room temperature-dependent operation (con-
■
stant operation with room thermostat):
System with one heating circuit without mixer. The
rooms are heated in accordance with the settings of
the room temperature controller/room thermostat
(accessories).
If the room temperature controller/room thermostat
issues a demand, the standard set flow temperature
is maintained. If there is no demand, the frost protec-
tion function is active.

OpenTherm controller

In systems with one heating circuit without mixer:

Venting program

During the venting program, the circulation pump will
be alternately switched on and off for 30 s over a
period of 20 min.
The 3-way diverter valve alternates between central
heating and DHW heating for a certain period of time.
The burner is switched off during the venting program.

Filling program

In the delivered condition, the 3-way diverter valve is
set to its central position, so the system can be filled
completely. After the control unit has been switched
on, the 3-way diverter valve no longer goes into its
central position.
If the system is to be filled with the control unit
switched on, the 3-way diverter valve is moved to its
central position in the filling program and the pump is
started.

Heating curve

The heating curves represent the relationship between
the outside temperature and the flow temperature.
Simplified: The lower the outside temperature, the
higher the flow temperature must be in order to reach
the set room temperature.
82
Constant operation without room thermostat:
■
The rooms are heated according to the set flow tem-
perature settings.
■ OpenTherm:
Rooms are heated in accordance with the settings of
the room temperature controller/room thermostat
(accessories). The OpenTherm controller specifies
the flow temperature for the heat generator.
The flow temperature and the DHW temperature are
based on the settings of the OpenTherm controller
(accessories).
Activate venting program: See chapter "Com-
missioning, inspection and maintenance".
Activate filling program: See chapter "Commis-
sioning, inspection and maintenance".
In this position, the control unit can be switched off and
the system can be filled completely. When the function
is enabled, the burner shuts down. The program auto-
matically becomes inactive after 20 min.
Factory settings:
Slope = 1.4
■
Level = 0
■