Dhw Heating; Heating The Dhw Loading Cylinder From Cold; Reheating When Dhw Is Drawn Off - Viessmann VITODENS 222-F Installation And Service Instructions Manual

Control functions
(cont.)
Reducing the heat-up time
During the transition from operation at reduced room
temperature to operation at standard room tempera-
ture or comfort room temperature, the flow tempera-
ture will be raised in accordance with the selected
heating curve.
Example
C
60
D
B
50
40
30 30
20
10
A
0
6 7
Time
Fig. 66
Start of operation at standard room temperature or
A
comfort room temperature
Set flow temperature in accordance with the set
B
heating curve

DHW heating

Heating the DHW loading cylinder from cold

The heating circuit pump is switched ON and the 3-
way diverter valve will be changed over, if the cylinder
temperature sensor captures a temperature lower than
the defaulted set value.
■ The cylinder loading pump is switched ON if the
boiler water temperature
The burner is switched ON if the boiler water temper-
■
ature set cylinder temperature, and the cylinder
≤
loading pump is switched ON when the required
boiler water temperature is reached.

Reheating when DHW is drawn off

When DHW is drawn off, cold water enters the lower
section of the loading cylinder.
The heating circuit pump is switched ON and the 3-
way diverter valve is changed over, if the cylinder tem-
perature sensor captures a temperature lower than the
defaulted set value.
8 9
set cylinder temperature.
≥
The value and duration of the additional increase in the
set flow temperature is adjusted in parameters 424.3
and 424.4.
Set flow temperature in accordance with parame-
C
ter 424.3
Duration of operation with higher set flow tempera-
D
ture in accordance with parameter 424.4:
60 min
The loading cylinder is heated up to the set cylinder
temperature. Heating stops when the specified temper-
ature has been reached at the cylinder temperature
sensor.
■ The cylinder loading pump is switched ON if the
boiler water temperature
The burner is switched ON if the boiler water temper-
■
ature set cylinder temperature, and the cylinder
≤
loading pump is switched ON when the required
boiler water temperature is reached.
DHW is regulated to the set temperature via the outlet
temperature sensor.
Function description
set cylinder temperature.
≥
103