Filling Program; Heating Curve - Viessmann Vitovalor PT2 Installation And Service Instructions For Contractors

Control functions
(cont.)
Activate venting program: See "Commissioning,
inspection and maintenance".

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 outdoor temperature, the
higher the flow temperature must be in order to reach
the room temperature set point.
Factory settings:
Slope = 1.4
■
Level = 0
■
90
80
70
60
50
40
30
10
Fig. 103
Slope setting ranges:
Underfloor heating systems: 0.2 to 0.8
■
■ Low temperature heating systems: 0.8 to 1.6
Slope
5 0 -5 -10 -15 -20
Outside temperature in °C
Activate filling program: See "Commissioning,
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.
Note
If heating circuits with mixer are present in the heating
system: The flow temperature of the heat generator is
one differential temperature higher than the flow tem-
perature for the heating circuits with mixer. Differential
temperature in delivered condition set to 8 K.
The differential temperature can be adjusted using the
following parameters:
■ Heating circuit 2: Parameter 934.5
■ Heating circuit 3: Parameter 935.5
■ Heating circuit 4 (if installed): Parameter 936.5
1.4
1.2
1.0
0.8
0.6
0.4
0.2
-25 -30
Set room temperature
Standard room temperature or comfort room tem-
perature
Individually adjustable for each heating circuit.
Function description
149