Viessmann VITOTRONIC 100 GC1 Installation And Service Instructions Manual page 106

Functional description
Heating Circuit Control
Brief description
The supply temperature of the boiler
circuit (A1) corresponds to the boiler
water temperature.
Functions
The boiler circuit (A1) is dependent on
the boiler water temperature and its
control range limits.
DHW Tank Temperature Control
Brief description
The DHW tank temperature control is a
constant value control. It operates on
the basis of switching the DHW pump
on and off.
Functions
Frost protection function
If the domestic hot water temperature
falls below 10°C / 50°F, the domestic
hot water DHW tank is heated to
20°C / 68°F.
Additional function for domestic hot
water heating
For temporarily increasing the DHW
tank temperature at selectable intervals
→ this provides additional assurance
that bacteria are eliminated.
This function is activated when a
second DHW setpoint value is selected
via coding address "58" and a time is
selected via coding address "63".
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Coding addresses which influence the
heating circuit control
55, 56, 58, 5A to 63, 6A, 6b.
Upper limit of control range
Electronic maximum limit
Setting range: 1 to 127°C /
34 to 261°F.
Change via coding address "C6".
Lower limit of control range
Electronic minimum limit
Setting range: 1 to 127°C /
34 to 261°F.
Change via coding address "C5".
The switching differential is ±2.5°C /
4.5°F.
During DHW tank heating, a constant
maximum boiler water temperature is
set (20°C / 36°F above the set-point
DHW tank temperature, variable via
Heating with the additional function
takes place daily at the time of the
1st domestic hot water heating
period.
Set-point domestic hot water
temperature
The set-point domestic hot water
temperature can be set in the range of
10 to 60°C / 50 to 140°F. The
setpoint range can be extended to
95°C / 203°F via coding address
"56".
Domestic hot water temperature
With priority control:
While the DHW tank is being
heated, the set-point supply
temperature value is set to
0°C / 32°F.
Without priority control:
The heating circuit control
continues to operate as normal
with the setpoint value unchanged.
coding address "60") and space
heating is switched off (DHW tank
priority control optional).
Additional control facilities
The domestic hot water supply
can be blocked and released via
change-over of the heating program.
System with DHW heating
The functions described above also
apply in conjunction with DHW
heatings.
Set the following codings:
"4C: 1", "4E: 1", "55: 3".