Viessmann VITOLIGNO 300-C Installation And Service Instructions Manual page 176

Function description
Control functions
(cont.)
Heating curve of the heating water buffer cylinder
Heating curve
100 °C
E
B
A
65 °C
56 °C
C
20 10 0
Slope
Change with
Fig. 106
Lower limit "Minimum buffer temperature"
A
B Upper limit "Maximum buffer temperature"
Heating curve (level and slope)
C
Limited heating curve (level and slope, minimum
D
and maximum limits)
Boiler modulating range
E
Set value determination (set buffer temperature)
The "Set buffer temperature
following factors:
■ Outside temperature
■ Heating curve "Slope and level" (extended menu)
■ Minimum limit "Minimum buffer temperature"
(code 35)
Maximum limit "Maximum buffer temperature"
■
(code 34)
Characteristic curve for the heating water buffer cyl-
C
inder is determined subject to the outside temperature
and the values selected for slope and level.
The determined curve C
temperature" and "Maximum buffer temperature"
A
.
B
The value of "Limited heating curve"
subject to the outside temperature and is specified as
the "Set buffer temperature
Actual value determination (actual buffer tempera-
ture)
The "Actual buffer temperature
the average value of the following buffer temperature
sensors: Buffer temperature sensor 1 (top) and the
sensor specified in "Buffer cylinder charging up to sen-
sor" (code 36), including the buffer temperature sen-
sors between them.
Set buffer temperature = set temperature for the heating water buffer cylinder
*10
Actual buffer temperature = actual temperature value (currently present temperature) of the heating water buffer cylinder
*11
Set system temperature = highest temperature demanded by all control circuits (heating circuits, DHW heating)
*12
176
Buffer
D
76 °C
71 °C
-20
-10 -30
0.5
(
" is calculated from the
*10
is limited by "Minimum buffer
is determined
D
*10 " .
*11 " is determined from
Time program
You can set these charging times by adjusting the time
program for the heating water buffer cylinder.
During the set time phases, the charging level of the
heating water buffer cylinder has an effect on the boiler
operation.
Operating modes (operating program)
The operating modes "Automatic", "Manual" and
"Off" are available for regulating the heating water
buffer cylinder.
The influence of the operating modes on the combus-
tion output of the boiler in turn influences the runtime
and the start-up frequency of the boiler.
The heating water buffer cylinder operating modes are
set in the "Extended menu" under "Buffer".
Note
The following factors have a positive effect on the
service life and efficiency of the heating system:
■ Low start-up frequency
■ Highest possible combustion output
■ Longest possible runtime of the boiler (no cycling)
"Automatic"
In automatic mode, the automatically determined
"Set buffer temperature
*10
"Manual"
In manual mode, a fixed set temperature can be selec-
ted for the heating water buffer cylinder.
When manual mode is selected, the set value is
entered in the "Extended menu" under "Buffer".
"Off"
In "Off" mode the heating water buffer cylinder is
heated by the boiler.
The heating water buffer cylinder has no influence on
the boiler output control.
The boiler regulates to the set boiler water temperature
("Extended menu").
In "Off" mode, the boiler starts when the "Set system
temperature " is undershot. Once the boiler reaches
*12
the "Boiler water temperature limit" (code 0E) for an
adjustable time of "Boiler water temperature delay"
(code 0F), the boiler is switched off.
" is used.