Viessmann VITOTRONIC 100 GC1B Installation And Service Instructions Manual page 97

Vitotronic 100, GC1B Installation and Service
DHW Tank Control
The DHW tank Goes Cold (set value −2.5 K; change via
coding address "59"):
The set boiler water temperature is adjusted 20 K
higher than the set DHW temperature (adjustable
via coding address "60").
Pump on:
– Starting the circulation pump for DHW tank heating
subject to the boiler water temperature (code "61:0"):
The circulation pump starts when the boiler water
temperature is 7 K higher than the DHW temperature.
– Immediate start of the circulation pump for DHW tank
heating (code "61:1").
The DHW tank is hot:
The control unit checks whether the boiler will still
be required to supply heating energy after the DHW
tank has been heated up or whether residual boiler heat
should be transferred to the DHW tank. Accordingly,
the control unit determines the burner and circulation
pump stop times to prevent the set DHW temperature
being substantially exceeded after the DHW tank has
been heated up.
Code "55:2" in category 3 "DHW", tank temperature
control with 2 DHW tank temperature sensors
DHW tank temperature sensor 1 enables the circulation
pump for DHW tank heating and is evaluated for stop
conditions during the pump run-on time.
DHW tank temperature sensor 2:
DHW tank heating will start early if a lot of hot water
is drawn off. DHW tank heating will terminate early
if no hot water is drawn off.
DHW tank goes cold:
Set value −2.5 K, adjustable via coding address "59"
or
Actual DHW temperature at sensor 2 < set DHW
temperature x factor for start time (adjustment via
coding address "69").
The DHW tank is hot:
Set value +2.5 K
and
Actual DHW temperature at sensor 2>set DHW
temperature x factor for stop time (adjustment via
coding address "68").
(continued)
Coding "55:3" in category 3 "DHW", tank temperature
control, primary store system
The DHW tank Goes Cold (set value −2.5 K; change
via coding address "59"):
The set boiler water temperature is adjusted 20 K
higher than the set DHW temperature (adjustable via
coding address "60").
The primary pump in the primary store system starts.
The 3-way mixing valve opens and then regulates
to the defaulted set DHW temperature.
The circulation pump for DHW tank heating cycles
(short term ON and OFF) until the set supply
temperature has been reached (set DHW temperature
+ 5 K). Then it runs constantly.
If, during heating, the actual value falls below the
required set temperature, the circulation pump for DHW
tank heating will temporarily cycle again.
The DHW tank is Hot:
DHW tank temperature sensor 1:
Actual value ≥ set value
and
DHW tank temperature sensor 2:
Actual value > set value −1.5 K:
The set boiler water temperature is returned to the
weather-compensated set value.
The circulation pump for DHW tank heating stops
immediately when the 3-way mixing valve is fully opened
or
The circulation pump for DHW tank heating stops after
expiry of the run-on time that is selected via coding
address "62".
Function Description
97